Extended Idle 97-01 Install

[2000XJSPORT]

Hello,
With the help of JEEPZZ and many others. I have completed the install for the extended idle. It works great and it was not hard to install. As asked by JEEPZZ to reply on the activation light. I too could not get it to light up. I connected the ground, fused panel lamps dimmer switch signal, and the idle actuator, but did not connect fused ignition switch run. When I did connect the fused ignition switch run wire up to the correct color and number off the A/C plug. The switch did not work at all and the lights all dimmed in the car. So I cut it loose and left it unhooked. Also I did bypass C100 and C107 when running the wire from the switch to PCM C1 #12. If anyone knows how to get the light to work. I would really appreciate it.
Alex

http://i9.photobucket.com/albums/a75/ADSBNSF/EXTidle.jpg
http://i9.photobucket.com/albums/a75/ADSBNSF/Picture025.jpg
http://i9.photobucket.com/albums/a75/ADSBNSF/PCMC1.jpg

[JEEPZZ]

Looks good! :D



Original thread for wiring and install right here: http://http://www.naxja.org/forum/showthread.php?t=77285

[2000XJSPORT]

Thanks, Just wish i could of got that light working, but atleast it works. I had one question. Does your switch work when the headlight are on? Mine does not when I have the head lights on.
Alex

[langer1]

Its not a activation light, it only lights when your instrument lights are on and it should work with headlights on.
One other thing, you see wire called "Other" C107?
If you connect that wire to what ever you want like a "light bar" your high idle will come on by it's self

[2000XJSPORT]

So that little orange light does not light up when the switch is pressed? The backlight does come on when the headlights are on. I do not know why it does not work with head lights on.
Alex

[langer1]

So that little orange light does not light up when the switch is pressed? The backlight does come on when the headlights are on. I do not know why it does not work with head lights on.
Alex
Sorry I was thinking only about the back light, you could have 3and 4 reversed the indicator should work.

[2000XJSPORT]

I have all the wires in the right spots just as it shows in the OEM wiring diagram. I dont have the fused ignition switch output (RUN) #3 wire hooked up because when I did the switch did not work at all and when pushed it made the lights in the car dim. It says that wire is an external splice, but i do not know what that means. Does anyone know the difference between a internal and external splice as stated in the OEM repair manual.
Alex

http://i9.photobucket.com/albums/a75/ADSBNSF/switch.jpg

[langer1]

I have all the wires in the right spots just as it shows in the OEM wiring diagram. I don't have the fused ignition switch output (RUN) wire hooked up because when I did the switch did not work at all and when pushed it made the lights in the car dim. It says that wire is an external splice, but i do not know what that means. Does anyone know the difference between a internal and external splice as stated in the OEM repair manual.

Thats where I'm confused, with Fused ign (run) disconnected high idle should not work.
Were are you getting the 12v to feed the switch?
It looks like you have two white wires with your bypass, could you have them switched?

[2000XJSPORT]

Thats where I'm confused, with Fused ign (run) disconnected high idle should not work.
Were are you getting the 12v to feed the switch?
It looks like you have two white wires with your bypass, could you have them switched?

It works without Fused ign (run). Im not sure why, but it does and I do not really know what Fused ign (run) is. The switch is getting a ground and a dimmer switch signal. The connector that I use is from a fog lamp harness which was not used in the install of my fog lamps. So I used it and just added the a wire to PCM 12. I used a white wire to run to PCM 12. The disconnected grey wire with a red connector on it in the last pic is from C107 where it dead ends before entering the harness to under the dash at C100.
Alex
#1 is Black (Ground) #2 White spicing into the already connected purple (Idle actuator) #3 Blue (Fused ing output (RUN) and #4 (Fused panel lamps dimmer signal)
http://i9.photobucket.com/albums/a75/ADSBNSF/EXTIdleSwitchWires.jpg

[casm]

Thanks for the closeup of the 4-switch panel - I ordered mine last week (driving light switch is eventually going in there), and was wondering how it would look in detail.

[dynamite44]

when you bought the switch, did it come with the little wire pigtail thingy that plugs into the back of it?
that makes things really easy. i was sort of wondering how you connected the wires.

[2000XJSPORT]

I used the pigtail that was in my XJ. When I got fog lamps installed they used a new harness and just left the factory one next to the switch bezel. If you have it it is black and it will give you a ground and the backlight. All you have to do it shave off the key on the plug so that it will fit into the ext idle switch. Then I just ran a wire to PCM 12. But like I have said before I do not know how to get the light to turn on when the switch is pushed and how to connect the fused ign. output. Other wise the switch works with out that connected.
Alex

[langer1]

Compairing Front fog to Extend idle connectors 1 and 4 are reversed.
On Fog 1 is OR 4 is Bk. On High idle 1is BK and 4 is OR.
That ign (run) is any wire thats hot only in run and not start you don't want Hi idle when your cranking.

[2000XJSPORT]

I notice that too and I have checked the connection to make sure I have the wires in the right spots. Would you have any idea to why when I connect ign (run) to the plug the switch will not work at all and light dim when pressed. Also do you think ign (run ) wire has anything to do with that light comming on?
Alex

[langer1]

I notice that too and I have checked the connection to make sure I have the wires in the right spots. Would you have any idea to why when I connect ign (run) to the plug the switch will not work at all and light dim when pressed. Also do you think ign (run ) wire has anything to do with that light comming on?
Alex
Yes the ground wire is on the wrong terminal,

[2000XJSPORT]

So I guess I will switch them and see what happens. I will flip the orange and the black and then try it. The switch works the way it is now so if this does not work I will go back to the way I have it now. Sound ok?
thanks for the help too.
Alex

[langer1]

So I guess I will switch them and see what happens. I will flip the orange and the black and then try it. The switch works the way it is now so if this does not work I will go back to the way I have it now. Sound ok?
thanks for the help too.
Alex
The fog light power goes off when the high beam are on so that's your other problem.
The (run) ign wire should power the High Idle circut not the fog light power.

[2000XJSPORT]

Ok thanks. I will switch the wire and see if this fixes the problems. Thanks again.
Alex

[2000XJSPORT]

Problem fixed. I had the wires wrong in the plug and I also did connect the Ign (Run) wire. The Ext Idle switch lights up and works great. Thanks again langer1 and JEEPZZ for all your help.
Alex

http://i9.photobucket.com/albums/a75/ADSBNSF/ExtIdle4.jpg

[langer1]

Great :loveu:

[TacticalFats]

That's looks great.

I have grounded the same wire, but I use a ghetto toggle up on the black spot to the right of the intrument cluser. It's right under the ghetto toggle for the aux fan, and above the ghetto red momentary switch for the air horn.

[JEEPZZ]

Problem fixed. I had the wires wrong in the plug and I also did connect the Ign (Run) wire. The Ext Idle switch lights up and works great. Thanks again langer1 and JEEPZZ for all your help.
Alex

http://i9.photobucket.com/albums/a75/ADSBNSF/ExtIdle4.jpg
That's great! Does your illumination still work correctly too?
Looks like I'll have to go and reroute mine. :)

[2000XJSPORT]

JEEPZZ,
Yeah it works great. With all 4 wires hooked up, it lights up and turns on.
Alex

[CommandoXJ96]

alright... i know this says 97-01 install, but I think this would be the best place to ask this. On PCM 12 on the 1996 XJ the wire run through is a dark blue wire with an orange stripe, but it does the same thing supposedly (according to other threads it should be that color even and it is afterall pcm12).

So i disconnected my battery, disconnected the large harness and spliced into the blue and orange PCM12 wire. I extended the wire out (good connection I am sure of...) reattached the harness, the battery and started her up. then i grounded the wire... nothing. tried grounding and then starting... regular idle rpm. i disconnected the battery etc and redid the connection and tried everything again... No results again.

the only result i did notice is that now my check engine light is on - Code 23. Code 23 is the intake manifold temperature sensor giving too much voltage. I think this may be just becuase i moved the iac sensor to the air box (a long time ago), and I've seen this code show up before and go away by itself when i had originally moved the sensor.

I have no clue what I did wrong, but im not sure what else i can do now - other then ask you guys for some help. i sure could use it.

[langer1]

I don't know if you have the correct wire but it needs 12+ not ground for high idle.
The ground on the switch is only for the light.
Find Power Steerling sens grounding that wire should give you high idle.
Just be carefull if you get the wrong wire you will blow the ECU.
The wire should be DK Blu-Wht or Violet.

[CommandoXJ96]

well, i misread earlier then, i was under the impression the ground was what needed to complete the curcuit. i attempted connecting the wire to the battery 12v+ and still got no response. still have code 23 and the CEL. dang... thx for filling me in on the positive though. dont know what to do about this now...

[langer1]

well, i misread earlier then, i was under the impression the ground was what needed to complete the curcuit. i attempted connecting the wire to the battery 12v+ and still got no response. still have code 23 and the CEL. dang... thx for filling me in on the positive though. dont know what to do about this now...
That was for the 2000 yours is totaly different.
Like I said it looks like like your can ground the PS SW input on yours.

[CommandoXJ96]

i guess ill look into it more tommorow when i have some time and just put it back how it was.

[CommandoXJ96]

well... from looks of this post it should be the same except for the dashboard pieces. should be the blue-orange wire in pcm 12 for my 96, and again "should" serve the same purpose.

Here's some info regarding the computer wire connection to be used for the extended idle setup:

EXTENDED IDLE SWITCH TEST
OPTIONAL POLICE PACKAGE ONLY
The extended idle switch is used to raise engine idle speed to approximately 1000 rpm when the auto shifter is in either Park or Neutral position. A rocker-type switch (extended idle switch) is mounted to instrument panel. This switch is available only with 4.0L engine when supplied with optional police package.

The extended idle switch will control a ground circuit going to the powertrain control module (PCM) When a ground signal (through the switch) has been received at pin/cavity A-12 (circuit K78) of the PCM, engine idle speed will increase.


For 1984-1992 I6 XJs and all I4 XJs:
Not an option in computer pin-out.

For 1993-1995 I6 XJs:
PCM Pin # 10, Purple, [60-pin connector] (Switch On: 1V, Off:12V)

For 1996 I6 XJs:
PCM Pin # 12, dark blue/orange, [Black "A" 32-pin connector] (Switch On: 1V, Off:12V)

For 1997-2000 I6 XJs:
PCM Pin # 12, gray, [Black "A" 32-pin connector] (Switch On: 1V, Off:12V)

http://home.earthlink.net/~jeepzz/sitebuildercontent/sitebuilderpictures/pcm.jpg

Switch location for 97+ (optional 4 opening switch bezel)

http://home.earthlink.net/~jeepzz/sitebuildercontent/sitebuilderpictures/xj_switch_ext_idle.jpg

[jeepinarkansas]

Why would one want this option?

[langer1]

Why would one want this option?
For running lots of lighting and even a winch when setting still.

[langer1]

I would be carfull with that switch if you have small kids or something.
If your stopped at a light and someone flips that switch your going to rear end someone.

[CommandoXJ96]

huh? what switch?

those images are qouted from another thread/another poster.

but from what it looks like, pcm 12 on the 1996 xj is the same as 97-01 save for the color of the wire.

i still can't figure out this damned code 23 with the CEL. I even cleared the engines computer of the code and it keeps coming back. im getting really frustrated now with just trying to get the code to go away.... for now im gonna save doing the switch untill I can get the CEL to go off. It seems to have a higher idle now... starts and goes to 1400ish and slowly backs down to 900 rpm.

[CommandoXJ96]

ooops, double post... crap.

[JEEPZZ]

well... from looks of this post it should be the same except for the dashboard pieces. should be the blue-orange wire in pcm 12 for my 96, and again "should" serve the same purpose.
Keep in mind the picture and diagram of that post are for the 97+ XJ's only.
I would be carfull with that switch if you have small kids or something.
If your stopped at a light and someone flips that switch your going to rear end someone.
The ext idle circuit will not activate unless the auto trans is in neutral or park.

[CommandoXJ96]

Keep in mind the picture and diagram of that post are for the 97+ XJ's only.


well, the info posted in that says: For 96 XJs right above 97-01... and says the same thing, but the wire should be orange-blue. i know the rest of this is only 97-01, but 96 has the same PCM lay-out as the 97-01 except the wire colors. The 95 and earliers have completely different wireing... 96 is just differeing on colors of wires.

[JEEPZZ]

well, the info posted in that says: For 96 XJs right above 97-01... and says the same thing, but the wire should be orange-blue. i know the rest of this is only 97-01, but 96 has the same PCM lay-out as the 97-01 except the wire colors. The 95 and earliers have completely different wireing... 96 is just differeing on colors of wires.
You will use the same ext idle switch as all pre97 XJ's so your wiring should still be different than the 97+ (at least at the switch).

http://www.fototime.com/A06B19E19177F51/standard.jpg

[CommandoXJ96]

yeah, its not the switch im haveing trouble wireing... I've done fan switches and fog lights/roof lights before, no problem. My problem is simply getting the PCM#12 wire to do anything when 12+ volts are added, and aside from the wires color, the wire in pcm12 should serve the same purpose on the 96 as it does in 97-01. The wireing (for the pcm harness and stuff) is functionally the same on the 96 in the PCM as the later models. Thats what im haveing real trouble figureing out. I have left the switch out of the equation at the moment and have simply been attaching the wire to an outlet in the under-dash fuse box. Never any RPM boost in Nuetral/Park when i have it 'on' though.

[langer1]

yeah, its not the switch im haveing trouble wireing... I've done fan switches and fog lights/roof lights before, no problem. My problem is simply getting the PCM#12 wire to do anything when 12+ volts are added, and aside from the wires color, the wire in pcm12 should serve the same purpose on the 96 as it does in 97-01. The wireing (for the pcm harness and stuff) is functionally the same on the 96 in the PCM as the later models. Thats what im haveing real trouble figureing out. I have left the switch out of the equation at the moment and have simply been attaching the wire to an outlet in the under-dash fuse box. Never any RPM boost in Nuetral/Park when i have it 'on' though.
There was mid-year changes in 96 some were the same as 91-95 and latter production runs were the same as 97-99

[JEEPZZ]

My problem is simply getting the PCM#12 wire to do anything when 12+ volts are added, and aside from the wires color, the wire in pcm12 should serve the same purpose on the 96 as it does in 97-01.
On my 97, I can get the high idle circuit by grounding pin #12, NOT 12v+.
If yours is the same as 97+, try a direct ground of pin #12 to activate high idle. Also just to clarify, you do have a 4.0L and auto trans correct?

[CommandoXJ96]

yes, it is 4.0/AW4 setup. Its a January 96...

For 1993-1995 I6 XJs:
PCM Pin # 10, Purple, [60-pin connector] (Switch On: 1V, Off:12V)

For 1996 I6 XJs:
PCM Pin # 12, dark blue/orange, [Black "A" 32-pin connector] (Switch On: 1V, Off:12V)

For 1997-2000 I6 XJs:
PCM Pin # 12, gray, [Black "A" 32-pin connector] (Switch On: 1V, Off:12V)

It has the Black 32 pin connector, not a 60 pin connector though, so I would assume it follows the later year models....

[JEEPZZ]

It has the Black 32 pin connector, not a 60 pin connector though, so I would assume it follows the later year models....
Yep, try grounding it.

[mjydrafter]

I have a '92 4.0l aw4. I have the Ext Idle switch/bezel & wiring connector out of a '96. I had no wire on pin 10, but I was able to add one to the harness pretty easily. All of the wiring diagrams I have looked at list pin 10 as the power steering switch or ext idle circuit. All one should have do is ground this to pin 11 or 12 and it should work, right? Another question I have, is the power to the switch just for the indicator light on the switch? The wire connector has 4 wires 2 of wich are black and connected to the same terminal. I assume they are connected; a black one to pin 11 or 12 and another black one to a body ground, one 10 amp fused power for the indicator light, and one is the connection to pin 10. I think this is correct, but I don't want to fry my ecm.

[2000XJSPORT]

I grounded PCM#12 before I hooked up the switch and it raise the idle to 1000rpms. It should work like JEEPZZ said.
Alex

[langer1]

This may help.
http://img.photobucket.com/albums/v11/langer1/jeep/FSM/idleextend.jpg

[CommandoXJ96]

well...grounding it is what i initially was doing. i tried grounding that wire again, no switch... still no rise in rpm on mine. im not sure what im doing wrong, but if im not seeing it, im not sure how you guys would be able to point it out to me either.

[2000XJSPORT]

If you have the switch. You could always wire it up and see if it works with the switch. Maybe the switch does something to make it happen you never know. I'm not sure what else I can add that would be of help.
Alex

[langer1]

well...grounding it is what i initially was doing. i tried grounding that wire again, no switch... still no rise in rpm on mine. im not sure what im doing wrong, but if im not seeing it, im not sure how you guys would be able to point it out to me either.
The power steering switch was only used on the 2.5 engine, it's possible that the wiring in a 4.0 is not even connected or the ECU is not programed for it.
Also make sure pin 30 is grounded when your in park.

[CommandoXJ96]

The power steering switch was only used on the 2.5 engine, it's possible that the wiring in a 4.0 is not even connected or the ECU is not programed for it.
Also make sure pin 30 is grounded when your in park.

it has the wireing it looks like for the pcm 12... but now that i look at it, there is no wire in Pin30. in fact, the side that connects to the pins doesnt even have a metal contact, and it doesnt appear to go through to the other side where the wires meet the contacts/harness. any idea how to add in a ground to pin 30? what is pin 30 anyhow?

[langer1]

it has the wireing it looks like for the pcm 12... but now that i look at it, there is no wire in Pin30. in fact, the side that connects to the pins doesn't even have a metal contact, and it doesn't appear to go through to the other side where the wires meet the contacts/harness. any idea how to add in a ground to pin 30? what is pin 30 anyhow?
My bad pin 30 is for a 95 with the 60 pin connector and it's neutral/park sense.

[CommandoXJ96]

ok... so im just gonna type out what i assume is what i should be doin... b/c im really just doing something wrong...

im under the impression that i am to tap into the pcm12 and simply ground the wire to somewhere on the frame and it should immediately (or very quickly) raise my RPM as i idle in Park or Nuetral. < this doesnt yield any results for me for some reason... but since i first tried it my CEL has not wanted to turn off, and it gives me Code 23. (Air intake sensor voltage above/below acceptable level... checked sensor and wireing... didnt cut anyne besides pcm 12 - everything else is fine..)

or am i supposed to give the PCM#12 12V+ and then ground it when i want the RPM to go up? (not brave enuf to simply try this one without asking)

[langer1]

ok... so im just gonna type out what i assume is what i should be doin... b/c im really just doing something wrong...

im under the impression that i am to tap into the pcm12 and simply ground the wire to somewhere on the frame and it should immediately (or very quickly) raise my RPM as i idle in Park or Nuetral. < this doesnt yield any results for me for some reason... but since i first tried it my CEL has not wanted to turn off, and it gives me Code 23. (Air intake sensor voltage above/below acceptable level... checked sensor and wireing... didnt cut anyne besides pcm 12 - everything else is fine..)

or am i supposed to give the PCM#12 12V+ and then ground it when i want the RPM to go up? (not brave enuf to simply try this one without asking)
Just ground it, thats all.
It may not work until you fix the code 23 intake air temp sensor.

[CommandoXJ96]

now where it says Fused Ign. (run) in the wireing diagrams... am i supposed to run 12+V to the switch along with the ground to make it work somehow... or is that simply to illuminate the switch or something? maybe grounding the wire alone isnt working b/c of the CEL code and ill just have to take care of that first(like you said Langer1). Went into checker auto to get it read, and its High input not low/no input... so maybe the air sensor wire is connected in the first PCM harness (a) and i cut into that wire somehow? if i knew which wire the Air Intake Manifold temp sensor ran through maybe i could get a good look at that and see if i somehow damanged it.

[langer1]

now where it says Fused Ign. (run) in the wireing diagrams... am i supposed to run 12+V to the switch along with the ground to make it work somehow... or is that simply to illuminate the switch or something? maybe grounding the wire alone isnt working b/c of the CEL code and ill just have to take care of that first(like you said Langer1). Went into checker auto to get it read, and its High input not low/no input... so maybe the air sensor wire is connected in the first PCM harness (a) and i cut into that wire somehow? if i knew which wire the Air Intake Manifold temp sensor ran through maybe i could get a good look at that and see if i somehow damanged it.
No 12v+ goes to one side of the indcator light the other side goes to the switch with the wire to PCM 12 and one wire all by it's self from the switch to ground.

[CommandoXJ96]

i guess ill just try and hunt down the sensor problem first... no telling what else is 'crossed' or incorrectly makeing contact if that is going on, so theres really no point in trying to ground pcm12 if theres bigger problems turning on the CEL. i guess when i have that fixed ill give it another go and post up.

[casm]

Yeah, this thread's been dead for a while, but it's got me slightly confused as to what wiring goes where so I'm resurrecting it. Basically, I'm using a cut-off fog light wiring pigtail and can't figure out how to translate what the FSM recommends to the colours I actually have on the pigtail. As I'm reading it, I should have:

Black: Ground
Grey: Pin 12 on the PCM connector
Dark Blue / White: Fused iginition switch output
Orange: Fuse panel lights dimmer switch signal

Translating this over to what's on the pigtail:

Black: Ground
Purple: Pin 12 on the PCM connector
Light blue: Fused ignition switch output
Orange: Fuse panel lights dimmer switch signal

Does this look right? I've got to clean up a bunch of messy wiring back there from the CB and GPS this weekend anyway, so would like to make the extended idle switch actually do something useful beyond making me hit the defroster when I'm aiming for the rear wiper ;)

Also, what's the best location to splice for the fused ignition switch output and dimmer switch signal? On the back of one of the other switches in the bezel? My bezel's fully-populated, so I have plenty to choose from.

[2000XJSPORT]

If you are using a fog lamp pigtail then the wiring goes like this. Colors are:

Black: Fuse panel lights dimmer switch signal
Purple:Fused ignition switch output
Light blue: Pin 12 on the PCM connector
Orange: Ground

This is just on the pigtail because a fog lamp pigtail colors are changed around and black and orange are reversed. Other wise it still is

Black: Ground
Grey: Pin 12 on the PCM connector
Dark Blue / White: Fused iginition switch output
Orange: Fuse panel lights dimmer switch signal

For the Dark Blue / White: Fused iginition switch output. I connected it to the AC controller right above the pannel. it is the same color and number in the wiring diagram. Just splice into it and it works great in getting the switch to light up.
Hope this helps. If not just send me a message.
Alex

http://i9.photobucket.com/albums/a75/ADSBNSF/Picture001.jpg

[CommandoXJ96]

glad to see this thread alive again (Kinda...)
My CEL deal was fixed but grounding PCM 12 still yields no result. I'm using 18 guage wire on the tap to the ground... but its a ground so it *shouldnt* matter - correct?

i know im pissing everyone off becuase I've got a 96 and everyone else is talking about a 97 or newer - but aside from the color of the wire its all the same (in theory...). If anybody else has it workin on a 96 xj I'd love to hear from you.

[casm]

Hope this helps. If not just send me a message.

Thanks, that made things a lot clearer, and I think I see now where I screwed up on the wiring. I'll have at it again this weekend and let you know how it goes.

[red_01_xj]

thanks for the awesome write up...it took me close to a half hour to do the hole thing...one thing i did differently i ran the wire that light up the switch to the 12v power outlet that only runs when the key is in...i also taped my backlight and ground into the fog light switch

[langer1]

Why would one want this option?
To keep your battery charging when parked and all your lights on.

[ihscoutlover]

John, this is the only extended idle posting I found. Is there a way to get this information for a '96 and older-mine being a '94 XJ? I would like to make this modification if possible. I would also need schematics and the such. Thanks

Jeff

[langer1]

94's are also covered. PCM12 is the connection point.

[langer1]

For 1993-1995 I6 XJs:
PCM Pin # 10, Purple, [60-pin connector] (Switch On: 1V, Off:12V)

For 1996 I6 XJs:
PCM Pin # 12, dark blue/orange, [Black "A" 32-pin connector] (Switch On: 1V, Off:12V)

For 1997-2000 I6 XJs:
PCM Pin # 12, gray, [Black "A" 32-pin connector] (Switch On: 1V, Off:12V)

It has the Black 32 pin connector, not a 60 pin connector though, so I would assume it follows the later year models....

[ihscoutlover]

Then John do I just need the switch from a '96 or older unit? Thanks for the update

Jeff

[langer1]

Then John do I just need the switch from a '96 or older unit? Thanks for the update

Jeff
You can use any switch you like.

[ihscoutlover]

John, then by your schematics, is the switch taking 12V away from the PCM or adding it to it to get the higher idle, and how does it get tied into the wiring since my '94 doesn't have it?? I kinda understand your directions, is it just a two or three wire switch?? Thanks

Jeff

[langer1]

When Extended Idle is on it grounds pin #10. Not sure about what you mean about a three wire switch, if the switch has a indicator light is has three wires but one is just the light.

[Blaine B.]

Thanks for the information!

[Blaine B.]

How would I wire up a standard lighted switch (3 inputs) for this?

These switches have a ground, input +12, and output +12.

To get it to light when the switch is activated, how would I wire it? If I switched around the +12 and ground I don't think that would work.

When the extended idle is not activated, what voltage is it reading? If it was +12 then it would be fine to reverse +12 and ground.....if not, it wouldn't be ok.

Any ideas and do you know what I am asking? Thanks!

[casm]

It seems like there's always a new reason to dig this thread up again... :D

Spent a good part of the afternoon cleaning up some ratty wiring I'd introduced by installing various things. Something I'm curious about:

http://i9.photobucket.com/albums/a75/ADSBNSF/PCMC1.jpg

If you look at the spliced wire on the PCM, you'll notice that in 2000XJSport's installation he left the other end of the wire dangling from where it originally exited the harness; I've got the same thing. Does anyone know where this wire terminates? I'd like to eliminate the stray ghetto wire I've got running to the PCM now and use the factory one if at all possible.

Yeah, I know that six months ago would've been the appropriate time to consider this, but I was just so giddy with enthusiasm at the idea of being able to raise the idle with the flick of a switch that the idea never really occurred to me ;)

[red_01_xj]

i left mine intact im not sure where it would go

[Blaine B.]

My 95 doesn't even have this wire in the plug. Any idea how to add it so I could run it to a switch?

[red_01_xj]

the pre 96 had a differnet wiring

[Blaine B.]

I know, using the chart with Pin # for OBD I (for my 95) and corresponding wire color, I know my computer plug doesn't have that. I'd like to add it.....any ideas on how to add it to the plug if it doesn't already have it?

[casm]

I know, using the chart with Pin # for OBD I (for my 95) and corresponding wire color, I know my computer plug doesn't have that. I'd like to add it.....any ideas on how to add it to the plug if it doesn't already have it?

Pull the PCM connector on a junkyard XJ. Take it apart, cannibalise one of the pins, then add it in to your connector along with the wiring. A complete PITA to do, but probably your only non-ghetto option.

Something just occurred to me, though - you are checking pin 10 and not pin 12, right? See this post (http://www.naxja.org/forum/showpost.php?p=721965&postcount=41) on page three (http://www.naxja.org/forum/showthread.php?t=79549&page=3) of this thread to verify. I just want to be sure we're definitely talking about the same thing.

[Blaine B.]

Yep, 10, and no straight purple wire either.

[casm]

Yep, 10, and no straight purple wire either.

Check page three. I seem to remember seeing a post re: someone in the same position.

[CommandoXJ96]

well my problem continues (have only messed with it a couple times) where the PCM 12 on the 32 PIN (96 XJ pcm) won't raise the idle when grounded. i tried messing with it again when i saw this thread active again and tried to figure out what was up by using a light - Pin 12 to the positive and ground to the negative wire of the light. I could of swore that the light wasnt lighting up at all but i realized when i held my hand over it - it had the slightest dim glow. this is a light from behind the dash! its really small... the 12+V that comes from the PCM must not have a good connection or something - which is why my idle is staying the same i guess?

anybody know what might be up/ how to fix this? i tried tightening up all the connections, etc to get a better signal, i have no clue why it wont just bump the idle.

[Blaine B.]

Anybody with an OBD1 and extended idle, can u take a pic pointing out the wire?

[2offroad]

Do you cut the wire or splice into it and and a ground?

[casm]

Do you cut the wire or splice into it and and a ground?

DO NOT PERMANENTLY GROUND THE WIRE!

This is important. Unless you want your XJ idling at approximately 1100-1200 RPM all the time and all the issues that this may bring with it, permanently grounding the Extended Idle pin is a BAD idea.

So, to answer your question: cut not splice, and add a switch that will allow it to go from +12V to ground when you want the idle to be bumped up.

[2offroad]

I forgot to add switch, Why not splice into harness? the wire doesn't go anywhere on stock harness, correct?

[scoobyxj]

well my problem continues (have only messed with it a couple times) where the PCM 12 on the 32 PIN (96 XJ pcm) won't raise the idle when grounded. i tried messing with it again when i saw this thread active again and tried to figure out what was up by using a light - Pin 12 to the positive and ground to the negative wire of the light. I could of swore that the light wasn't lighting up at all but i realized when i held my hand over it - it had the slightest dim glow. this is a light from behind the dash! its really small... the 12+V that comes from the PCM must not have a good connection or something - which is why my idle is staying the same i guess?

anybody know what might be up/ how to fix this? i tried tightening up all the connections, etc to get a better signal, i have no clue why it wont just bump the idle.

Never ever ever ever use a test light when tracing vehicle electronics! You can, and will fry sensitive cpu's! You always should use a multimeter. The reason the light was dim is because the circuit you where testing can probably only handle a few Milli-amps, and that light bulb (even though is is a small low wattage indicator lamp) requires more current (amperage) than the circuit can deliver.

Example

A 2w bulb at 12V will draw .166 A (2/12=.166)
Now .166A is = to 166mA (. goes three places to the right)
Most possessor chips can only handle a few micro-amps in which case that .166A load would become 166,000 micro-amps, and using a transistor might let it handle a few Milli-amps. Just guessing, I would bet you fried the circuit, by using a test bulb instead of a meter.

[casm]

I forgot to add switch, Why not splice into harness?

Oh, OK. I understand what you're looking at doing now. Splicing into the stock harness would be fine; AFAIK that's how everyone's done it so far.

the wire doesn't go anywhere on stock harness, correct?

From what I can make out in the FSM, it supposedly comes out somewhere in the area of the kick panel under the steering column, but I've so far been unable to trace it. Remember that that's not a 'dead' wire in normal use: it should have +12V going through it to tell the PCM not to engage the extended idle, so it has to terminate at an ignition-switched source somewhere.

[Blaine B.]

Are some OBD-1 XJ's not equipped with this wire or pin? I took a quick peek and I swore the corresponding terminal for a 95 in OBD-1 (according to the chart) was not present on my PCM plug.

[2offroad]

I did it today and it worked fine, spliced into the grey wire and ran a wire into the console to a switch and then to ground, flip switch on and the idle goes up to about 1100-1200 rpm, drops back to normal in gear.

[casm]

I did it today and it worked fine, spliced into the grey wire and ran a wire into the console to a switch and then to ground, flip switch on and the idle goes up to about 1100-1200 rpm, drops back to normal in gear.

I'm slightly confused here - are you supplying +12V to pin 12 when the switch is off? Not quite following how your switch works.

[2offroad]

I spliced into the wire and the switch goes to ground, +12v is there from the harness.

[casm]

I spliced into the wire and the switch goes to ground, +12v is there from the harness.

OK, makes sense.

[Blaine B.]

If you have a lighted switch with "normal" instructions it's kind of backwards......you have to switch around negative/positive on the switch in order for it to light when your high-idle is on, and not backwards.....I have a diagram somewhere.

[casm]

If you have a lighted switch with "normal" instructions it's kind of backwards......you have to switch around negative/positive on the switch in order for it to light when your high-idle is on, and not backwards.....I have a diagram somewhere.

Stop, stop, stop. Everyone take a step back from this for a minute; the original information is starting to get lost in a sea of supposition. As stated on page 4 (http://www.naxja.org/forum/showthread.php?t=79549&page=4) of this thread:

If you are using a fog lamp pigtail then the wiring goes like this. Colors are:

Black: Fuse panel lights dimmer switch signal
Purple:Fused ignition switch output
Light blue: Pin 12 on the PCM connector
Orange: Ground

This is just on the pigtail because a fog lamp pigtail colors are changed around and black and orange are reversed. Other wise it still is

Black: Ground
Grey: Pin 12 on the PCM connector
Dark Blue / White: Fused iginition switch output
Orange: Fuse panel lights dimmer switch signal

For the Dark Blue / White: Fused iginition switch output. I connected it to the AC controller right above the pannel. it is the same color and number in the wiring diagram. Just splice into it and it works great in getting the switch to light up.
Hope this helps. If not just send me a message.

Obviously, this only applies in two related cases: '97 and up XJs, and using a foglamp pigtail to wire in the OEM Extended Idle switch. However, it should essentially be used as a roadmap for using a different switch. Repeating this here for the sake of accuracy; there's too much inaccuracy creeping into this thread right now.

[2offroad]

Yes, my posts are about using non OEM parts on a '98 to do the upgrade.

[BlueCuda]

I spliced into the wire and the switch goes to ground, +12v is there from the harness.

did you spline into the wire near the ECM or did you find the wire inside the cabin area. Thanks

[CommandoXJ96]

Never ever ever ever use a test light when tracing vehicle electronics! You can, and will fry sensitive cpu's!
....
Just guessing, I would bet you fried the circuit, by using a test bulb instead of a meter.

Dangit. Well I won't be doing that again. But my next thought is... if i fried the circuit- the light should have gone competely out when I tried it last - correct? Everything else is fine.... I suppose I could try a multimeter and if it still reads anything - that should be an indicator as to if it was fried or not - right?

[BlueCuda]

Thanks for all the info guys. I just got mine wired up and working. I held off until I found a thread where they got the light working..glad I did. Next up is the overhead console install, power windows will be the final option I want to add but not looking real good lol to much work.

[JEEPZZ]

Thanks for all the info guys. I just got mine wired up and working. I held off until I found a thread where they got the light working..glad I did. Next up is the overhead console install, power windows will be the final option I want to add but not looking real good lol to much work.
Sounds like you're going down the same road I did with my wifes 97 Sport. I added OEM power windows, locks (including hatch lock), keyless entry with the overhead console, Infiniti tweeters. Next is factory fogs.
The ext idle is in my Jeep, along with power heated leather seats & complete interior from a 99 Limited. That includeds the headliner with the molded in speakers to replace my speaker bar that came in the 97's. upgrade, upgrade, upgrade.

I did the power conversion mods over a weekend. Let me know when your ready and I'll see if I can help walk you through it. Just post a thread and send me a PM with the thread link so I don't miss it; that way we can help out others looking to do the same mod. :D

[BlueCuda]

Sounds like you're going down the same road I did with my wifes 97 Sport. I added OEM power windows, locks (including hatch lock), keyless entry with the overhead console, Infiniti tweeters. Next is factory fogs.
The ext idle is in my Jeep, along with power heated leather seats & complete interior from a 99 Limited. That includeds the headliner with the molded in speakers to replace my speaker bar that came in the 97's. upgrade, upgrade, upgrade.

I did the power conversion mods over a weekend. Let me know when your ready and I'll see if I can help walk you through it. Just post a thread and send me a PM with the thread link so I don't miss it; that way we can help out others looking to do the same mod. :D

I thought I had a donor for all the power mods. Its a white Classic thats loaded other than leather. I was thinking how nice it was that it had 3 good white doors with power windows and locks. It doesn't look all the bad but somehow its tweeked enough only one of the doors will open, the others are friction shut with no signs of opening. I was able to get the console and wiring from it though. I am not sure I will want to mess with changing 4 window regulators.

[ponyracer1]

Where do you get one of the factory extended idle switches?? Part number??

Can you get just the switch? I'd like to replace my fog light switch with that one since there no longer with us.


Thanks

[casm]

Where do you get one of the factory extended idle switches?? Part number??

Extended Idle Switch - 56008728.

4-Switch Bezel - 4897505AE.

Note that these numbers are for '97 and up only.

I got both of mine from allchryslerparts.com (http://www.allchryslerparts.com). Ran about $60 or so for both, IIRC. Since you're in the UK, though, you should be able to find a 4-switch bezel in the scrapyard - my memory is that they were standard on XJs with front foglights in the EU.

Can you get just the switch? I'd like to replace my fog light switch with that one since there no longer with us.

Yes, you can get just the switch by itself. Of course, if you ever intend to wire front fogs back in again it might be handy to keep the existing one.

[ponyracer1]

Extended Idle Switch - 56008728.

4-Switch Bezel - 4897505AE.

Note that these numbers are for '97 and up only.

I got both of mine from allchryslerparts.com (http://www.allchryslerparts.com). Ran about $60 or so for both, IIRC. Since you're in the UK, though, you should be able to find a 4-switch bezel in the scrapyard - my memory is that they were standard on XJs with front foglights in the EU.



Yes, you can get just the switch by itself. Of course, if you ever intend to wire front fogs back in again it might be handy to keep the existing one.


HMMMM thanks for the info and the tip, I'll do some checking and post up what I find.

[JEEPZZ]

I thought I had a donor for all the power mods. Its a white Classic thats loaded other than leather. I was thinking how nice it was that it had 3 good white doors with power windows and locks. It doesn't look all the bad but somehow its tweeked enough only one of the doors will open, the others are friction shut with no signs of opening. I was able to get the console and wiring from it though. I am not sure I will want to mess with changing 4 window regulators.
I swapped out all of the door guts: regs, locks, wiring and panels. I actually think it's easier to do that than try to find 4 matching color straight doors. You'll need the main cabin wiring harness from the donor Jeep too.

[2000XJSPORT]

Hello all,
I have been getting a lot of emails asking how I installed the Extended Idle in my XJ. I have not forgotten to reply, I am just taking some time to put a complete writeup together on the install. It will include what I know and also input I have gotten from the great members of NAXJA. It will be like the Overhead Console writeup I did a while back. Will be coming SOON.
Thanks,
Alex

[Blaine B.]

Wundebar!

[JEEPZZ]

Hello all,
I have been getting a lot of emails asking how I installed the Extended Idle in my XJ. I have not forgotten to reply...
You and me both. :peace:
A step by step write up would be great (but isn't all that already what this thread is?). :D

[2000XJSPORT]

Very true.

Writeup will be completed by February 12th.

[ShaunBaker]

Kick @$$! even though i learned from this that all i have to do is ground pin 12 then bam 1000RPM, pretty cool feature. Now all i have to do is find the switch and wiring harness for CHEAP!!!lol where can I get the best deal on it? i'm a broke college kid

[2000XJSPORT]

The switch most likely will have to be purchased at a dealership. Think it is $40.00 bucks. At a junk yard you might be able to find an XJ and all you would have to do is get a fog light pigtail. One other thing you could look for a Government XJ or a police one and see if it has the whole set up. I know how it is to be in college. I just saved a little money here and there and finally put it together.

[klennop]

Hello all,
I have been getting a lot of emails asking how I installed the Extended Idle in my XJ. I have not forgotten to reply, I am just taking some time to put a complete writeup together on the install. It will include what I know and also input I have gotten from the great members of NAXJA. It will be like the Overhead Console writeup I did a while back. Will be coming SOON.
Thanks,
Alex

That would be awesome because reading through all the posts of how to get it to work correctly is a pain. A nice cleaned up set of directions would be great!!

[mikereid350]

why do you need a extended idle swich system??

[klennop]

why do you need a extended idle swich system??

This was answered a couple of times in this thread. If you are running a lot of aux. equipment (lights, winch, etc), hitting the extended idle will put less strain on the battery and alt. It holds the RPMs up a little higher so the alternator puts out some more juice.

I am also going to use it in cold weather to get the jeep warmed up a little faster. I am sick of the -25 to -35 below temps we have had all week!!!

[casm]

I am also going to use it in cold weather to get the jeep warmed up a little faster. I am sick of the -25 to -35 below temps we have had all week!!!

Not having used mine in seriously cold weather, I can't say this with absolute authority, but I can tell you this: it does a good job of keeping the coolant at normal temperatures when parked and idling for long periods in very hot weather. Not sure it'll work for a fast warm-up in the cold.

[klennop]

Not having used mine in seriously cold weather, I can't say this with absolute authority, but I can tell you this: it does a good job of keeping the coolant at normal temperatures when parked and idling for long periods in very hot weather. Not sure it'll work for a fast warm-up in the cold.

Yeah I agree in the manual it says if you are towing a lot etc. that having the engine rev a little more will help cool it down. Hopefully if I do this mod it will help get it up to temp too, it is worth a shot. I am also going to install a block heater this summer to help out for next winter.

[2000XJSPORT]

With the Extended Idle it does warm up the engine faster. I love it and use it all the time on cold days.

[klennop]

Sorry to bring this back up but I have another question. Could you just have this wired up so it does it all the time? Would there really be a problem or any issues with this besides sucking more gas.

[Blaine B.]

All the time? You can't have it engauged when you're in gear.

[rpyne]

You will use the same ext idle switch as all pre97 XJ's so your wiring should still be different than the 97+ (at least at the switch).

http://www.fototime.com/A06B19E19177F51/standard.jpg
Can anyone provide part numbers for this bezel and switch?

[vetteboy]

So here's an idea - how about for us manual-shift guys?

Is there a way to wire in this thing to kick the idle up a little bit as a sort of electronic-hand-throttle? Maybe a mod to the IAS to get the idle speed up to 1500 or so? Using my diagnostic computer I can dial the idle up to 2000 RPM just by playing with the IAS setting so there's probably some way I can patch a resistor in to make that happen without the diagnostic thing.

That'd be kind of neat.

[klennop]

All the time? You can't have it engauged when you're in gear.

I know that it doesn't stay active when you are in gear. It only works when in neutral or park. What I was wondering is if you could wire it up so the extended idle was activated everytime when you are in park or neutral without using a switch. Would there really be a problem or any issues with this besides sucking more gas. Sorry I wasn't so specific in my original post.

[Ecomike]

I would think that you could add a variable resistor in series with the TPS (between the matting female and male pin C at the TPS / wiring harness connector) to do it. The only problem is finding the right variable resistor (potentiometer). Might take a mini powerstat to do it well.

It would take some experimentation. Sounds like a Mod-section topic now.

[vetteboy]

I would think that you could add a variable resistor in series with the TPS (between the matting female and male pin C at the TPS / wiring harness connector) to do it. The only problem is finding the right variable resistor (potentiometer). Might take a mini powerstat to do it well.

It would take some experimentation. Sounds like a Mod-section topic now.

Hmm...perhaps. In thinking about it a little more, I'm pretty sure the IAC uses a stepper motor which would be a little trickier to take manual control of. There's a box that does exactly what I'm describing that'll go from 0-3000 RPM with pushbutton control but it's $200+ and I'd rather find something I can do myself.

I'll try probing some sensors today maybe and see what I can come up with.

[Ecomike]

I took some ohm meter readings once on my Renix, 87 TPS while it was attached and read 4.28 to 6.66 K-Ohms from B to C (according to my notes).

You might go to Radio Shack and pick up some resistors, 10, 100, 500, 1000 ohms, temporarily install each one and see what it does to the idle speed. From that data you could determine a range you need for the variable reisistor.

[vetteboy]

Would the TPS have an effect on things though? I always kinda thought it was more of a passive sensor that helped decide the injector duty cycle. If you "trick" the ECU into thinking the throttle is open more than it actually is, and it starts dumping more fuel in, I think it would either result in a rich mixture and not work as well....unless it adjusts the IAC to compensate for it. Hmm.

Most people would just run a bike shifter cable to the throttle arm at this point and call it good.

[Ecomike]

Would the TPS have an effect on things though? I always kinda thought it was more of a passive sensor that helped decide the injector duty cycle. If you "trick" the ECU into thinking the throttle is open more than it actually is, and it starts dumping more fuel in, I think it would either result in a rich mixture and not work as well....unless it adjusts the IAC to compensate for it. Hmm.

Most people would just run a bike shifter cable to the throttle arm at this point and call it good.
The TPS tells the ECU where your foot is on the gas peddle! The extra resistor will lie to the ECU for you and tell it you want more RPMs. The ECU will adjust the fuel and the IAC together to increase the idle. I learned this the hard way when I had ground problems that added to the TPS resistance via the ground leg, Pin C, and made mine idle to fast when the ground got intermitently loose!

My experience is with the older Renix Jeeps, 1987 in this case, but they are similar enough in later years that it should work on the new models as well, unless they made the newer computers smarter, which I doubt. Just try it.

But now that I think more about it you may need to install it on the two C gound pin connections, and / or recalibrate the TPS at a higher voltage first with the Variable resistor at a dead short first to be able to use it in the B pin connection.

[JEEPZZ]

I know that it doesn't stay active when you are in gear. It only works when in neutral or park. What I was wondering is if you could wire it up so the extended idle was activated everytime when you are in park or neutral without using a switch. Would there really be a problem or any issues with this besides sucking more gas. Sorry I wasn't so specific in my original post.
Just ground pin 12 and the system will always be active without the need for a switch. Doing this will kick the idle up everytime you go into neutral or park, just like leaving the switch in the constant 'on' position.

[JEEPZZ]

(re:pre97)Can anyone provide part numbers for this bezel and switch?
The foglight switch and the ext idle switch have the same part number, only the bezel label is different. I'm sure someone will post the part number before I get a chance to dig them up, again. :D

[klennop]

Just ground pin 12 and the system will always be active without the need for a switch. Doing this will kick the idle up everytime you go into neutral or park, just like leaving the switch in the constant 'on' position.

Are there any drawbacks/problems to doing it this way though?

[JEEPZZ]

Are there any drawbacks/problems to doing it this way though?
Other than the obvious (not being able to manually control it), I don't see a problem with it.

[krelja]

Extended Idle Switch - 56008728.

4-Switch Bezel - 4897505AE.

Note that these numbers are for '97 and up only.

I got both of mine from allchryslerparts.com (http://www.allchryslerparts.com). Ran about $60 or so for both, IIRC.


Yes, you can get just the switch by itself. Of course, if you ever intend to wire front fogs back in again it might be handy to keep the existing one.

you can also get the stuff @ www.jeepsareus.com as well oh yeah and for some reason when I searched for the part I needed to keep the . on the end to otherwise it would say no parts found

[rpyne]

The foglight switch and the ext idle switch have the same part number, only the bezel label is different. I'm sure someone will post the part number before I get a chance to dig them up, again. :D
No one has. The switch I can find, but I haven't been able to find the part number for the bezel.

I'm still working on figuring out the wiring needed for my 88.

[Ivan]

No one has. The switch I can find, but I haven't been able to find the part number for the bezel.

I'm still working on figuring out the wiring needed for my 88.

4897505AD - 4 Slot Switch Bezel for 97's and newer....
I got mine online at one of those All Chrysler Parts websites.....

[JEEPZZ]

4897505AD - 4 Slot Switch Bezel for 97's and newer....
I got mine online at one of those All Chrysler Parts websites.....
He was talking about this one for the pre97 models:

http://www.fototime.com/A06B19E19177F51/standard.jpg

No one has. The switch I can find, but I haven't been able to find the part number for the bezel.

I'm still working on figuring out the wiring needed for my 88.
You're going to have to get creative on wiring it up since 92 & older were not set up for the ext idle circuit.
If you've got one of your 2 slots open on the bezel (4 actually, 2 per side) just throw the switch in the unused slot. Don't worry about the ext idle labeled bezel.

[rpyne]

You're going to have to get creative on wiring it up since 92 & older were not set up for it.
I had it all figured out for my 87 2.5, but I haven't got it yet for my 88 4.0. On the 87, it was as simple as using the same system used for the A/C which activated a solenoid that opened up a vacuum line to raise the idle.

I think I can do it in a similar fashion on the 88 using a signal to the ECU that detects the A/C calling for the compressor to turn on. Just haven't yet had good enough weather to work outside when I had time to experiment.

[XJesse]

Any ideas of how to add extended idle to a 97 4.0 with a 5spd? I am considering adding a wire to the pcm 12 pin but am hesitant because i have no idea if it would work or possibly screw something up.
any info would be helpfull. especiallly in regards to adding a wire to pcm 12.

[Blaine B.]

Just curious - does a 95 have the "power steering pressure sense switch?"

I don't see any wires running to my power steering pump......

[JEEPZZ]

Just curious - does a 95 have the "power steering pressure sense switch?"

I don't see any wires running to my power steering pump......
The power steering switch replaces the ext idle circuit only on the 4 cyl motor.

[Blaine B.]

Ah. OK....

It jumps the RPM's up when the wheels are turned at idle?

[JEEPZZ]

Ummm no. From what I've read, it's a completely different circuit in the 4 banger.

[RWB214]

Any ideas of how to add extended idle to a 97 4.0 with a 5spd? I am considering adding a wire to the pcm 12 pin but am hesitant because i have no idea if it would work or possibly screw something up.
any info would be helpfull. especiallly in regards to adding a wire to pcm 12.

I've been wondering the same thing: Would this work on my 99 5 spd? In addition, why not just use an aux switch that connects Pin #12 to ground?

[RWB214]

To whom it may concern I have confirmed that this mod will not work on a 99 5 spd. The hole for pin 12 was blocked to keep moisture out so I had to dismantle the connector and dremmel the plastic out. Putting the connector back together was a PITA, but I did it and with the engine idling I inserted a paper clip into pin 12 and connected it to ground. Nothing. I assume that even if the PCM's are the same(auto or manual), it requires some input from the auto transmision in order for the Ext Idle function to work.

[scoobyxj]

To whom it may concern I have confirmed that this mod will not work on a 99 5 spd. The hole for pin 12 was blocked to keep moisture out so I had to dismantle the connector and dremmel the plastic out. Putting the connector back together was a PITA, but I did it and with the engine idling I inserted a paper clip into pin 12 and connected it to ground. Nothing. I assume that even if the PCM's are the same(auto or manual), it requires some input from the auto transmision in order for the Ext Idle function to work.
The PCMs are not the same.

[fuelfox4949]

alright i am runnin a 97 xj auto 4.0 and i have a spot for an extra switch in my jeep all mine has is rear defog and rear wiper so with that blank spot if i buy extended idle switch what else will i need. if i pull the cover off will it be just a plug in or with i be splicing and adding wires. i have been reading these forums for 2 hours now. just wondering what i have to do? i have the spot for it just need to know how involved is this project. livin in mn its cold i want it to heat up quicker and run my aux stuff. if anyone has a step by step right up let me know. thanks p.m if ya can help.

[scottmcneal]

This write up is over a year old, but some of these guys are still here..

[IllianaXJ]

alright i am runnin a 97 xj auto 4.0 and i have a spot for an extra switch in my jeep all mine has is rear defog and rear wiper so with that blank spot if i buy extended idle switch what else will i need. if i pull the cover off will it be just a plug in or with i be splicing and adding wires. i have been reading these forums for 2 hours now. just wondering what i have to do? i have the spot for it just need to know how involved is this project. livin in mn its cold i want it to heat up quicker and run my aux stuff. if anyone has a step by step right up let me know. thanks p.m if ya can help.

Most likely that blank is for factory fogs. There will be a plug behind there, but won't do you any good. Run new wires in the manner described in this thread and put your switch in the blank.

The info is in this thread, I used it and mine works flawlessly.

[McQue]

I put one in my 01 xj a few months back...I mounted a toggle switch in the blank spot, tied one side of the switch to ground and the wire for the other side of the switch had to be run thru the firewall out to the PCM and I spliced into the correct wire going into the PCM. works fine.

[blackdoutxj]

what is an extended idle and whats the point/or used for?! sorry for my ignorance:(...just wondering

[casm]

alright i am runnin a 97 xj auto 4.0 and i have a spot for an extra switch in my jeep all mine has is rear defog and rear wiper so with that blank spot if i buy extended idle switch what else will i need. if i pull the cover off will it be just a plug in or with i be splicing and adding wires.

Just to clarify this point for anyone reading: it doesn't matter if you currently have 0, 1, 2, or 3 switches in your bezel; the install instructions are the same.

Take a look at this thread (http://www.naxja.org/forum/showthread.php?t=77285); there's further clarification of the wiring, etc. in there.

i have the spot for it just need to know how involved is this project.

The worst part for me was finding a foglight pigtail - everywhere I talked to wanted stupid amounts of money for one, until I found a place willing to mail-order a foglight switch with the pigtail and about 6" of wiring to me for $12 (IIRC). Total time to install it (not counting waiting for that part to arrive) was less than two hours.

what is an extended idle and whats the point/or used for?! sorry for my ignorance:(...just wondering

It was a police package option used to raise the engine idle while the tranny was in park or neutral. The idea was that it would improve cooling and battery charging while parked for long periods of time running lights, radios, etc. jeepsareus.com still has the parts necessary for the conversion.

[blackdoutxj]

hhmmm thats really cool!thanks!

[fyrfytr1717]

Here it is, the answers you've been looking for!

I just finished installing an Extended Idle Switch in my '99 Cherokee Classic 4.0 A/T. It functions properly, the backlit icon dims with the rest of the dash, and the indicator light comes on when the switch is activated. After reading through this thread a number of times, I feel there's still a lot of confusion out there as to how to wire this properly. I know I was still confused until I read a few different threads about this mod. Let's see if I can pull all the information together and clear it up for future reference.


1. All the necessary parts (minus the wiring pigtail) can be purchased from your dealer or any of the online Mopar parts sellers. I looked at just about every site and the one that consistently came up the cheapest was Mopar Discount Parts dot Com. They also had great customer service and the cheapest shipping rates I could find. Jeromy is a one man show, is very helpful on the phone, ships quickly, and kept me up to date on my order status every step of the way. Just to give you an idea of the expenses you may incur if you choose to do this mod, I have listed the prices from the above mentioned supplier at the time I made my purchase.

Extended Idle Switch - Part# 56008728 ($27.50)
http://i511.photobucket.com/albums/s359/fyrfytr1717/Extended%20Idle/ExtIdle3.jpg?t=1235197269

4 Switch Bezel - Part# 4897505AF ($48.58)
Finally found out this part is so damn expensive because it comes with both the cigar lighter and power outlets!
(Also, be aware that these 4 switch bezels have been discontinued and are therefore in limited supply)
http://i511.photobucket.com/albums/s359/fyrfytr1717/Extended%20Idle/ExtIdle2.jpg?t=1235197437

and if your Fog Light Switch has burned out like everyone else's (and you still want to use your OEM switch)...

Fog Light Switch - Part# - 5080861AA ($27.70)
If you want it to last this time, wire it correctly with a relay after the switch.
Mopar Fog Light Wiring Repair Kit (Part# - 5066442AA $111.22) is available if you've got the funds and you're not comfortable with making the upgrades yourself.
http://i511.photobucket.com/albums/s359/fyrfytr1717/Extended%20Idle/ExtIdle4.jpg?t=1235197583

The other part you will need is a pigtail for your new switch. You can use either a fog light pigtail, or a window defroster pigtail. I removed both from an XJ that was getting parted out. Both are shown in the following picture. You will notice that the orange and black leads are opposite each other. It really doesn't matter which one you use as the pinouts are numbered on the body of the connector for reference. Grey plug is the Defrost pigtail, black plug is the Fog Light pigtail.

http://i511.photobucket.com/albums/s359/fyrfytr1717/Extended%20Idle/ExtIdle1.jpg?t=1235202954


2. The Idle Actuator wire that gets connected to Pin A12 on the PCM has been pretty well covered. I did however follow the wiring schematic in hopes of tracking down the closest possible spot to tap into the existing (Solid Grey) wire. Turns out that it doesn't get much better than right next to the PCM. Unless you have the Police Package (in which case you probably don't need to do this mod) the Solid Grey wire runs from Pin A12 on the PCM to Pin 11 on Connector C107 which you will find right next to the transmission dipstick. That's it, it stops there. This connector is actually further away from the driver's side firewall hole than the PCM is. I guess you could split the loom, find the Solid Grey wire, and splice into it right next to the firewall hole if you really wanted to.

This brings me to my next point. As this Solid Grey wire is not connected to anything other than A12 on the PCM, it doesn't matter whether you choose to cut or splice the Solid Grey wire to make your connection. Electrically speaking, it's the same either way.


3. Extended Idle Switch wiring is as follows (per the FSM):
Pin #1 - Ground (Black on the OEM Ext Idle pigtail)
Pin #2 - Idle Actuator (Grey on the OEM Ext Idle pigtail)
Pin #3 - Fused Ignition Switch Output (RUN) (Dark Blue w/ White stripe on the OEM Ext Idle Pigtail)
Pin #4 - Fused Panel Lamps Dimmer Switch Signal (Orange on the OEM Ext Idle Pigtail)

Unless you managed to score a pigtail from a Police Package XJ, your pigtail will not match up. I chose to use the Defrost pigtail since the #1 & #4 (Black & Orange) leads are the same as the original pigtail. Here's the easiest way to wire it all up:

Connect Ext Idle Switch Pin #1 to Fog Lamp Switch Pin #4 (Black)
Connect Ext Idle Switch Pin #2 to your wire leading to A12 on the PCM
Connect Ext Idle Switch Pin #3 to A/C Heater Control Pin #2 (Dark Blue / White stripe)
Connect Ext Idle Switch Pin #4 to Fog Lamp Switch Pin #1 (Orange)

So why do you tie into A/C Heater Control Pin #2 instead of the hot lead on the Fog Lamp Switch? Because if you use the Fog Lamp Switch as your power source, your Ext Idle indicator light will only come on when your Fog Lights are allowed to come on (i.e. headlights on, high beams off). If you use the Fog Light Switch lead, your Ext Idle indicator light won't come on when your headlights are off and it will turn off anytime you turn on your high beams. Best reasons of all though... the A/C Heater Control wire is close enough that you don't need to extend your Ext Idle pigtail and it is the power source used when Ext Idle is a factory option as shown in the diagram below.

http://i511.photobucket.com/albums/s359/fyrfytr1717/Extended%20Idle/pic1.jpg?t=1235200231

You're probably saying, great, now I've got to figure out where the heck A/C Heater Control Pin #2 is too... It actually couldn't be easier. Directly above your new Ext Idle switch is the A/C Heater control knob (Hot/Cold). On the back of the knob you will find a plug with three wires. Follow the wires down and you will see they run right past the back of the Ext Idle Switch. The middle one is the Dark Blue with White stripe that you are looking for. Splice into it and connect it to Ext Idle Switch Pin #3. Easy as pie.


4. To get all the parts to fit together, you're going to have to do a little modifying.

Unless you managed to score the OEM Ext Idle pigtail, you're going to have to cut the little key tab off the plug in order for it to fit into the Ext Idle Switch. This is easily done with a razor blade as the plastic is quite soft.

For some reason, the Ext Idle Switch itself comes keyed the same as the Fog Light Switch. This being the case, both switches will only fit in hole #3 on the switch bezel. Not a problem if you eliminated your fog lights and are using the 3 switch bezel, but if you're using the 4 hole switch bezel, you will need to shave the key tab off the switch. This can again be done with a razor blade but is a bit more difficult as the switch housing plastic is much harder.

Well, I hope this clears up all the misconceptions and muddy information about performing this mod. Enjoy and happy extended idling... :greensmok

[Blaine B.]

Why not skip all of the costs for the damn 4 hole bezel along with the switch and just go and buy a black rocker switch and mount it somewhere and make it look clean? Sure it's not stock but you'll save a bunch of dime, that's for certain.

[CMAHON]

THIS IS A STUPID QUESTION BUT WHAT IS THE EXTENDED IDLE DO OR FOR WHAT REASON DO YOU NEED ONE?

[CMAHON]

ANSWERED OWN QUESTION.

[fyrfytr1717]

Why not skip all of the costs for the damn 4 hole bezel along with the switch and just go and buy a black rocker switch and mount it somewhere and make it look clean? Sure it's not stock but you'll save a bunch of dime, that's for certain.

Where's the cool factor in that? :cool:

I'm just providing the info, not trying to tell everyone this is the only way to go. If you've read through the last 10 pages and checked how many times this thread has been hit, then you know there are plenty of folks interested in making it look factory. Personally, my goal is to make my rig look as clean and OEM as possible while still making it a highly capable trail rig. This mod fits my criteria nicely...

[rehberg79]

Where's the cool factor in that? :cool:

I'm just providing the info, not trying to tell everyone this is the only way to go. If you've read through the last 10 pages and checked how many times this thread has been hit, then you know there are plenty of folks interested in making it look factory. Personally, my goal is to make my rig look as clean and OEM as possible while still making it a highly capable trail rig. This mod fits my criteria nicely...

Im with you, it looks good. I used you info and ordered my stuff this morning. Now just need to hunt down some pigtails.......

Mat

[Blaine B.]

Has anyone completed this modification with a pre 96 XJ? I plan to do it on my 95 (OBD-1) and have already gathered the missing pin from another junkyard-doner. Just have not completed it yet. It appears it will work on all OBD-2 (96-01) XJ's no problem but I thought I heard that not all of the OBD-1 computers will support the extended idle modification?

[Blaine B.]

Bump? I know this states for 97-01 but I do not see a thread for the previous years....thanks :)

[1997cherokee]

what does it do? raise the idle? I have a high idle on my cummins truck but not good to idle a diesel. never heard that on a gasser

[Begster]

The high idle raises the RPMS up to a point where the alternator will re-charge the battery better, as it works more efficiently at higher RPMS than idle. This feature is found on police cars as they frequently need to park with their headlights and wig-wags on for extended periods of time, and it would kill the battery if they didn't have this option.

Glad this thread got pulled back up, I'm definitely going to look into this for mine.

[Blaine B.]

Yes except it is odd that it is controlled by a switch. I know the Ford Police Interceptor's PCM's automatically raise the idle when in park or neutral, there is no switch to turn it on or off.

[fyrfytr1717]

Yes except it is odd that it is controlled by a switch. I know the Ford Police Interceptor's PCM's automatically raise the idle when in park or neutral, there is no switch to turn it on or off.

This would be even easier to do than the switch mod. Simply ground Pin A12 on the PCM permanently and leave out the switch. You will have high idle anytime you are in park or neutral.

On a side note, high idle is activated by a switch on all of the electronically controlled fire engines in our fleet. They automatically shed accessories and lights if the power draw out paces the alternator output. This is only a problem at idle though. Flip the high idle switch and you can run everything at same time.

Oh and Blaine, sorry I'm no help with your questions regarding pre '96 XJ's. My FSM is for a '99 and I really haven't come across any definitive information regarding this option on an older model. Should be easy enough to figure out by looking at the wiring diagram for your model year. Give it a try and maybe you can do a write up with some solid answers for this common question.

[Blaine B.]

I know which pin it is as I have seen a diagram for the PRE 96 XJ's however I thought I remember hearing that not all pre 96 OBD1 computers would accept the high idle modification.

Mine has the male pin on the PCM for the proper port for high idle but did not have the female recepticle in the PCM plug. I have some extras that I can insert into the PCM plug and give it a try, but I just wanted to make sure I would not fry anything.

I guess I'll have to try it one of these days now considering I have another ride now incase something goes bollocks!

[JEEPZZ]

Are some OBD-1 XJ's not equipped with this wire or pin? I took a quick peek and I swore the corresponding terminal for a 95 in OBD-1 (according to the chart) was not present on my PCM plug.

Manual trans XJ's and 2.5L XJ's do not have the ext idle circuit. Also anything older than 93.

[Blaine B.]

So basically my 95 with the 4.0 and AW4 should definitely work with the extended idle circuit as soon as I add the female connector into the plug?

[JEEPZZ]

So basically my 95 with the 4.0 and AW4 should definitely work with the extended idle circuit as soon as I add the female connector into the plug?

Get yourself a jumper wire or a test light, clamp one end to a good ground and probe the other to the #10 pin (on your 95). Your idle should jump up to the 1000-1200 range.

[Blaine B.]

Just did this "modification" with mine tonight, had to drill out the plug for pin #10 and then I added a pin. I did not add a switch but just have it grounded to the body for testing. It has no effect on my idle, I'm still idling (when in park or neutral of course) on the line directly below 1000..no change at all.

Anybody know what is the deal with this?

[fyrfytr1717]

Damn, I was hoping your post was going to be a success story... Again, wish I could help but I have no wiring diagram for pre '97. Now here's a silly question, does that pin you installed in the hole you drilled out actually connect to anything behind it, or is it just floating in there?

[Blaine B.]

Wierd, I grounded pin #10 as specified and even used a stock female pin thing in the plug.

Unless there is a difference between the civilian and police computers for XJ's? Although I didn't think there were since they weren't really police fleet vehicles for the most part...sure you could order extended idle and a 120 mph speedometer as part of a package but that is as far as I thought it went.

[Blaine B.]

I remember seeing a post dedicated to the installation of the extended idle function in OBD1 equipped XJ's. I've searched Naxja and other forums and I can't seem to find it anymore. Bah!

[Root Moose]

Spidey-sense remembers something about that too. I may be muddling things but maybe it didn't use the PCM pin 12 thing but hooked into the power steering or air con idle raise switch instead. Or maybe that was a work around... Maybe try using those items in a search and see if it leads to different threads?

[Root Moose]

Have you seen this thread? It seems to mention some stuff about the older generation but I didn't read it close enough to see if it helps.

http://www.naxja.org/forum/showthread.php?t=35197

Post #21 says for the 1996 ground pin #12 which should be dark blue and orange.

HTH

[Blaine B.]

I found the original thread I was thinking of but there is a link in that thread linking to THIS thread lol!

[eleduardok]

I too cleaned out pin 10 on 95 Country as it was blocked and not female in main plug. male end is there on PCM. I have tried jumping it through various methods. Have not gotten proper insert for PCM plug but my juggling and all methods should have at least grounded it. It does nothing so far. Will work some more on it tomorrow.
Blaine B. Any luck with your pin 10 trials?

[Blaine B.]

No luck, there was pretty much only one trial and it hasn't worked since. Still grounded though.

BTW my 95 is a Country as well.

[eleduardok]

Man I swear I spent half a day here looking at EVERY thread on this. Seemed simple enough, yet no one has an answer? Does ANYONE have one that works on a 95? I idle my truck a lot on job sites and in the woods and could use this option. I will grab a spare PCM and the female inserts this week at JY. I was just going to run a non-lighted switch in cab to complete ground, but I am glad I tried before tearing into interior. frustrating as it seems so simple.

[Blaine B.]

I have NOT heard confirmation from anybody who did this to an OBD1 equipped XJ. Besides the ones showing police XJ's at the wrecker with the OEM switch on the dash. Maybe those PCM's are in fact different for the Police XJ's. Just how Ford police PCM's differer vastly from the civilian counterparts. But then why would Jeep have the same pcm's used for police and civilian vehicles for OBD2 equipped XJ's?

Like I said oh well, was worth the try.

[eleduardok]

So I went to the state library and looked at every reference I could find, all show same PCM for both models and pin 10 for the switch. Not being very electrical, it looked the same on all diagrams, just a choice of 2 different color wires depending on manufacture date. I am stumped. My buddy is an engineer for cummins coming over tonight, said he would look and see what he thought...
Not that important, but I hate getting beat. ;) Ed

[Blaine B.]

I hope he figures something good out, lol...fingers crossed but doubtful.

[Blaine B.]

Anything new on this topic? I hope!

[eleduardok]

got busy and gave up for now.... upgrading electrical and new alternator will solve a lot of the issues for me, 140amp, plenty of amp down low, so things will be better. Seems no one knows anything about this, so I let it be.

[Blaine B.]

I am looking for a Denso 136amp from a 98 ZJ to upgrade, but that seems to be rather difficult. I was previously told that all Grand Cherokee Limited's had 136 amp but apparently that isn't so. Prior to 98 even the fully powered Limited ZJ's had 90 or 117 amp tops.

[compcrasher86]

Heres a nice little tutorial for those with 98's, I just did mine:

I decided not to make the splice right at the ECU just because it was kinda far from my switch, I wanted the shortest wire run, and I wanted it to be protected from the elements. So I pulled off the connector and confirmed pin A12 on the black connector. Then farther up the wiring harness, near the master brake cylinder area I picked through the harness in the split loom and found the "solid grey wire" everybody seemed to have. So I then shaved a bit of the insulation off with a razor knife and using a multimeter, confirmed it had continuity with pin A12. Be careful, there are plenty of grey wires in there with stripes, you don't want those!

(Just a little side note, I did trace the grey wire till it ended, and it ends in a wiring harness connector over by the distributor cap. There is a little plastic blocker over the other side of the connector that essentially caps the wire off. Police packages probably had a different wiring harness that had the grey wire on the other side of that connector and brought it into the dash. I chose over by the master cylinder because thats the closest accessible area to get through the firewall)

Then I cut the wire, and soldered my new extension wire in (I kept with grey just for color coding purposes), slipped a piece of heatshrink over, and re soldered the original wires back together. Slipped the heatshrink over and used a heatgun to seal it
http://i45.photobucket.com/albums/f88/CompCrasher86/DSC00695.jpg

Then I ran it along an adjacent wiring harness and through the rubber boot through the firewall by poking a hole and threading it through with a coathanger. This was by far the most time consuming part because the rubber boot was a PITA to pierce. I then popped the wire into the split loom and taped wherever it was loose. This shows where the wire crosses from the ECU harness over to the one that goes into the rubber boot in the firewall
http://i45.photobucket.com/albums/f88/CompCrasher86/DSC00697.jpg
For my ground I popped open the connector for the factory fogs and soldered a thin black wire to the gnd for the fog switch, popped the connector back together and voila
http://i45.photobucket.com/albums/f88/CompCrasher86/DSC00698.jpg
I cut out a piece of the factory blank and am using this temporary switch until I can bring myself to buy the factory one
http://i45.photobucket.com/albums/f88/CompCrasher86/DSC00700.jpg

Overall the job is invisible because the wires are well hidden and bound up, the connections were made well and waterproofed under the hood, and my extended idle switch works GREAT. Bumps it up to 1100/1200 rpm for me. I don't know how often I'll be using this but when I have to do a jump start or in hot situations, this switch will DEFINATELY be worth it

[Blaine B.]

Did anybody figure anything out for OBD1 XJ's and the extended idle? Are the PCM's different for the civilian XJ's and Police XJ's for OBD1? My extended idle in my 95 is still not working....

[dagr8tim]

If you have a lighted switch with "normal" instructions it's kind of backwards......you have to switch around negative/positive on the switch in order for it to light when your high-idle is on, and not backwards.....I have a diagram somewhere.

Just so I'm understanding it, on my Civi 97, there is no ext idle switch or the wiring behind the switch. Can I just tap the gray wire (pin 12) and run the wire to a 2 prong toggle. Then ground the other prong?

I'm assuming that electricity flows from pin 12 to ground. I'm just asking because I want the indicator light on my aftermarket switch to light up.

[Blaine B.]

A 2 prong toggle would be no problem. Yes, one side would be tapped to the grey wire and the other side would go to ground. Since it is not lighted there is no need for +12volts for the bulb.

[dagr8tim]

A 2 prong toggle would be no problem. Yes, one side would be tapped to the grey wire and the other side would go to ground. Since it is not lighted there is no need for +12volts for the bulb.

Cool, if I wanted a light would I need an extra wire, or would the 12 volts to ground from the gray wire be enough to power an indicator light?

[Blaine B.]

The ground for the bulb would not come from the grey wire. It would come from the wire that goes to ground on the switch itself.

The other 3rd terminal would need to receive +12 volts, probably also best accomplished by tying into one of the +12 volt leads for one of the other switches. Just to make sure it is switched and not a constant +12 volt source. IE not hot when the vehicle is off.

[dagr8tim]

The ground for the bulb would not come from the grey wire. It would come from the wire that goes to ground on the switch itself.

The other 3rd terminal would need to receive +12 volts, probably also best accomplished by tying into one of the +12 volt leads for one of the other switches. Just to make sure it is switched and not a constant +12 volt source. IE not hot when the vehicle is off.

You can get 2 terminal switches with an indicator light. You are saying that the power from the ECU that is going to ground could not power the indicator light as it pass through the switch when it is activated?

No bigs, I'm sure I can snag the power from my fog light switch, or even use the fog light switch (as I don't have fogs) for the ext idle switch. Thanks for all the help.

[smccollamjr]

I'm not up on LEDs, but incandescent light bulbs don't care which way electricity is flowing. Which leads me to believe you could connect 12v to the ground lug on the switch, ground one of the switched lugs, and connect the gray wire to the other. I've got a couple switches with LEDs lying around. I'll try connecting them backwards tomorrow and see what happens.

[fyrfytr1717]

Did anybody figure anything out for OBD1 XJ's and the extended idle? Are the PCM's different for the civilian XJ's and Police XJ's for OBD1? My extended idle in my 95 is still not working....

Wow Blaine, sorry to hear a solution for OBD1 still hasn't come around for you.

[fyrfytr1717]

You can get 2 terminal switches with an indicator light. You are saying that the power from the ECU that is going to ground could not power the indicator light as it pass through the switch when it is activated?

No bigs, I'm sure I can snag the power from my fog light switch, or even use the fog light switch (as I don't have fogs) for the ext idle switch. Thanks for all the help.

I'm not up on LEDs, but incandescent light bulbs don't care which way electricity is flowing. Which leads me to believe you could connect 12v to the ground lug on the switch, ground one of the switched lugs, and connect the gray wire to the other. I've got a couple switches with LEDs lying around. I'll try connecting them backwards tomorrow and see what happens.

Curious to see if this will work. Never really thought of the ECU as being a +12V source. I thought you were just supplying a ground "signal" to the ECU to activate the extended idle. However, I guess if you're grounding the circuit that means electrons are flowing through it. :dunno:

dagr8tim, keep in mind that if you do use the fog light circuit for your power source, it is only hot when your parking lights (or headlights) are on and your high beams are off. I'd tap into the dark blue w/ white tracer for an ignition switched 12V+ source if you end up needing one. Refer back to post #149 for more info.

[Blaine B.]

No, the ECU is not giving ground, you are feeding ground TO the ECU.

And then ground alone will not power a bulb, you will also need a +12volts source to light the indicator.

[fyrfytr1717]

Heres a nice little tutorial for those with 98's, I just did mine:

I decided not to make the splice right at the ECU just because it was kinda far from my switch, I wanted the shortest wire run, and I wanted it to be protected from the elements. So I pulled off the connector and confirmed pin A12 on the black connector. Then farther up the wiring harness, near the master brake cylinder area I picked through the harness in the split loom and found the "solid grey wire" everybody seemed to have. So I then shaved a bit of the insulation off with a razor knife and using a multimeter, confirmed it had continuity with pin A12. Be careful, there are plenty of grey wires in there with stripes, you don't want those!

(Just a little side note, I did trace the grey wire till it ended, and it ends in a wiring harness connector over by the distributor cap. There is a little plastic blocker over the other side of the connector that essentially caps the wire off. Police packages probably had a different wiring harness that had the grey wire on the other side of that connector and brought it into the dash. I chose over by the master cylinder because thats the closest accessible area to get through the firewall)

http://i45.photobucket.com/albums/f88/CompCrasher86/DSC00695.jpg


2. The Idle Actuator wire that gets connected to Pin A12 on the PCM has been pretty well covered. I did however follow the wiring schematic in hopes of tracking down the closest possible spot to tap into the existing (Solid Grey) wire. Turns out that it doesn't get much better than right next to the PCM. Unless you have the Police Package (in which case you probably don't need to do this mod) the Solid Grey wire runs from Pin A12 on the PCM to Pin 11 on Connector C107 which you will find right next to the transmission dipstick. That's it, it stops there. This connector is actually further away from the driver's side firewall hole than the PCM is. I guess you could split the loom, find the Solid Grey wire, and splice into it right next to the firewall hole if you really wanted to.

This brings me to my next point. As this Solid Grey wire is not connected to anything other than A12 on the PCM, it doesn't matter whether you choose to cut or splice the Solid Grey wire to make your connection. Electrically speaking, it's the same either way.

Was curious to see if some one was going to try this. Glad it worked for you.

Then I ran it along an adjacent wiring harness and through the rubber boot through the firewall by poking a hole and threading it through with a coathanger. This was by far the most time consuming part because the rubber boot was a PITA to pierce. I then popped the wire into the split loom and taped wherever it was loose. This shows where the wire crosses from the ECU harness over to the one that goes into the rubber boot in the firewall

I installed a grommet in the circle marked with an "X" in your above picture and ran it through there. Didn't want to mess with the boot and as I've got about a dozen other wires as well as a couple of air lines running through it, my boot would have looked like swiss cheese by the time I was done.

Overall the job is invisible because the wires are well hidden and bound up, the connections were made well and waterproofed under the hood, and my extended idle switch works GREAT. Bumps it up to 1100/1200 rpm for me. I don't know how often I'll be using this but when I have to do a jump start or in hot situations, this switch will DEFINATELY be worth it

Good work on the install. I like it clean like like that.:thumbup:

I find I use mine for jump starting, winching, running my air compressor, and most often, while sitting in line at the drive through window. Shift it into neutral and your idle kicks up, back into drive and it automatically kicks down. I figure I might as well make my alternator do a little work while I'm just sitting there...

[dagr8tim]

I'm not up on LEDs, but incandescent light bulbs don't care which way electricity is flowing. Which leads me to believe you could connect 12v to the ground lug on the switch, ground one of the switched lugs, and connect the gray wire to the other. I've got a couple switches with LEDs lying around. I'll try connecting them backwards tomorrow and see what happens.


With moving and everything else, I'm not going to be able to mess with this until the weekend after this coming one. Let me know how it goes.

My thought is if you are grounding the wire, you are drawing off whatever voltage is coming from the ECU. So why can't you use that voltage that you are draining off to ground to power a light.

[scavengerj]

Thanx to all for brining this thread back up. Definitely something I am going to be doing. Never truely understood the purpose until now. Duh.

I do have one question though, if going with a higher rated alt., is this mod needed?

[larjerr1]

Hello,
With the help of JEEPZZ and many others. I have completed the install for the extended idle. It works great and it was not hard to install. As asked by JEEPZZ to reply on the activation light. I too could not get it to light up. I connected the ground, fused panel lamps dimmer switch signal, and the idle actuator, but did not connect fused ignition switch run. When I did connect the fused ignition switch run wire up to the correct color and number off the A/C plug. The switch did not work at all and the lights all dimmed in the car. So I cut it loose and left it unhooked. Also I did bypass C100 and C107 when running the wire from the switch to PCM C1 #12. If anyone knows how to get the light to work. I would really appreciate it.
Alex

http://i9.photobucket.com/albums/a75/ADSBNSF/EXTidle.jpg
http://i9.photobucket.com/albums/a75/ADSBNSF/Picture025.jpg
http://i9.photobucket.com/albums/a75/ADSBNSF/PCMC1.jpg

Hey guys, just joined so i could post this, your local dealer can get the pigtail for a 97+ cherokee it's part #
68057305AA (It's about $30 online dealership)

Found it here..
http://dto.vftis.com/mopar/disclaimer.asp (http://dto.vftis.com/mopar/disclaimer.asp)
You can find most all connectors there.....

Btw, thanks for the schematic above. My 1998 factory service manual has the same drawing but with pins 1 and 4 reversed. Lucky I just blew a fuse and not the computer. It idled up but instantly blew the fan motor fuse and then when I cut off the switch it stayed idled high till i cut the jeep off and restarted.
Also there are numbers near the switch pins, and on the connector, but they mate up backwards. 1 to 4, 4 to 1. According to how the other switches are wired the numbers on the connector are the numbers to use. Anyone ever had to remove pins from the connector? I hate to do more splices...
Also it sure would be helpful if someone took a pic of the pigtail showing correct wire placement. I'm not positive still which is right..don't want to fry it for real next try....

[fyrfytr1717]

Nice find on the pigtails! Here's the pin out information for your extended idle switch. Refer back to post #149 in this thread for full details.

3. Extended Idle Switch wiring is as follows (per the FSM):
Pin #1 - Ground (Black on the OEM Ext Idle pigtail)
Pin #2 - Idle Actuator (Grey on the OEM Ext Idle pigtail)
Pin #3 - Fused Ignition Switch Output (RUN) (Dark Blue w/ White stripe on the OEM Ext Idle Pigtail)
Pin #4 - Fused Panel Lamps Dimmer Switch Signal (Orange on the OEM Ext Idle Pigtail)

Unless you managed to score a pigtail from a Police Package XJ, your pigtail will not match up. I chose to use the Defrost pigtail since the #1 & #4 (Black & Orange) leads are the same as the original pigtail. Here's the easiest way to wire it all up:

Connect Ext Idle Switch Pin #1 to Fog Lamp Switch Pin #4 (Black)
Connect Ext Idle Switch Pin #2 to your wire leading to A12 on the PCM
Connect Ext Idle Switch Pin #3 to A/C Heater Control Pin #2 (Dark Blue / White stripe)
Connect Ext Idle Switch Pin #4 to Fog Lamp Switch Pin #1 (Orange)

So why do you tie into A/C Heater Control Pin #2 instead of the hot lead on the Fog Lamp Switch? Because if you use the Fog Lamp Switch as your power source, your Ext Idle indicator light will only come on when your Fog Lights are allowed to come on (i.e. headlights on, high beams off). If you use the Fog Light Switch lead, your Ext Idle indicator light won't come on when your headlights are off and it will turn off anytime you turn on your high beams. Best reasons of all though... the A/C Heater Control wire is close enough that you don't need to extend your Ext Idle pigtail and it is the power source used when Ext Idle is a factory option as shown in the diagram below.

http://i511.photobucket.com/albums/s359/fyrfytr1717/Extended%20Idle/pic1.jpg?t=1235200231

You're probably saying, great, now I've got to figure out where the heck A/C Heater Control Pin #2 is too... It actually couldn't be easier. Directly above your new Ext Idle switch is the A/C Heater control knob (Hot/Cold). On the back of the knob you will find a plug with three wires. Follow the wires down and you will see they run right past the back of the Ext Idle Switch. The middle one is the Dark Blue with White stripe that you are looking for. Splice into it and connect it to Ext Idle Switch Pin #3. Easy as pie.

[Blaine B.]

Has anybody figured out why this will not work with OBD 1 non-police setup? Grounding the proper pin does absoultely nothing.....no change in idle RPM, no nothing. Never see any OBD1 XJ's in the junkyard which were ex-Police so scoring the Police PCM would be pretty much as rare as it gets. I thought it might be possible with the "civilian" PCM too, as it is with the OBD2 96-01's........

[mrtosh]

Quick question. How exactly does the enxtended idle switch work? Does it affect the TPS or the IAC causing them to open more?

[srmitchell]

I think it would have something to do with the cruise servo?

[kastein]

mrtosh, can't affect the TPS as that's a sensor not an actuator. It would have to open the IAC further or use the cruise servo to open the throttle further, yes. Not sure which but that's easy enough to answer... anyone have an XJ with no cruise, but with extended idle? Or can anyone with an XJ with cruise+extended idle unplug their cruise servo and try using the extended idle switch as a test?

[KGP416]

Looks like IAC, found this with the google button "Flip the switch on the dash, this connects between vechicle ground and pin A12 of the ECU wiring harness. When the ECU sees the signal switched this way, the ECU increases IAC motor to maintain 1000 rpm, but only IF the transmission is in N or P."

[ReverendOD]

Wonder if there is anyway to bypass it needing to be in N or P to keep the idle bumped up? I just stripped back the shielding of A12 and grounded it and mine works just fine, wish you could bypass the N/P deal though.

[Begster]

As far as I believe, you can't. But why would you need to? The extended idle is for when you aren't in the car, for when police officers need to be sitting for a while, and don't want to keep their foot on the gas. When you are in drive/reverse, you will usually be giving it gas anyways, which would defeat the need for the switch. If you are stopped and in drive, just kick it back to neutral.


Question for those who have done it. I got a factory extended idle switch and installed it. It works about 50% of the time. Usually it always works when I first turn the vehicle on, but if I've been driving for a while, it usually won't turn on.

I took the panel illumination wire and ground (orange and black) from the fog light pigtail, the dark blue power wire is spliced into the cigarette lighter/aux power circuit which is where my FSM says the oringal switch goes. And then I cut back the sheath of gray wire but didn't snip the wire, and just soldered the activation wire directly to that. do people usually just cut the gray #12 pin wire under the hood, and butt connect it to the lead coming from the switch?

[ReverendOD]

Why not when on the trail or in traffic even in drive have that extra few hundred RPM to aid in cooling and even running the A/C? I understand its not the factory intended purpose. You could bypass the Neutral Safety Switch but then your Cruise wouldent work and I love my cruise control.... lol

Also if this hasnt been noted before the extended Idle will not kick in until you come to a complete stop. I tried bumping it into Neutral and rolling to a stop, as soon as the spedo hit 0 the idle went up.

[whatevah]

Extra wear on the trans/torque converter is one reason. That extra power has to go somewhere.

[ReverendOD]

Extra wear on the trans/torque converter is one reason. That extra power has to go somewhere.

Your AC already raises the idle some another hundred RPM in D is not going to hurt the TQ converter.

[Pelican]

Forgetting for a moment the question as to why on earth you would want to increase the idle while in gear, I would think bypassing the NSS without affecting the cruise should take nothing more than a very simple relay circuit.

[badron]

Run the EX idle when in gear.
How about braking. The engine would be making more torque in Eidle and the slush converter would be locked up a bit more as you come to a stop. Taking in account how much bitching there is about stopping XJ with big tires. You wouldn't want to add any extra load on the brakes. brake Life expectance would be shorter. Dropping her in gear would raise hell with U joints too.
Ideas for OB1. Switch over to OB2. Yea lots of work for a fast idle.
A post stated that the stick and OB1 or 2.5 ECU don't have the right stuff for Eidle. IF THIS IS TRUE and I am going to try my 5 speed first including simulating the NSS to the ECU. IF this don't work how about installing a ECU from a Slush-O-Matic into the 5 speed. Sticks are installed auto XJ without switching ECUs. Why not switch the boxs.
Sorry you 2.5 no easy work around.
God made a few perfect XJ the rest have SLUSH-O-MATIC :)

[ReverendOD]

We have an old farm truck that has always run 1000+ idle and in 135,000 miles no transmission or u joint issues. Go Figure. I dont think the force were talking about here isnt as much as you think it is. I guess I should turn my A/C off when i come to a stop or drop it into gear then?

[whatevah]

If your AC doesn't work at idle, you've got other issues. Before my evaporator died, I had no problems letting it idle with the AC on max for extended lengths of time.

[Pelican]

I say go for it! Truth is, I've suspected for a long time that most of the people who are members of this forum are less than competent and the negative responses to your proposed idle kick-up while in gear finally confirm that. I was wavering myself until you mentioned the old farm truck.

As I said before, getting around the NSS/cruise problem should be easy. Reline those brakes and keep an eye on the old AW4 (extended warranty?) and you should be home free.

Good luck, although I probably wouldn't expect a lot of help from the hoi polloi on this one....

[Pelican]

And, on a slightly more serious note, it's your truck and you don't have to answer to anyone for whatever you may want to do to it, but I don't see much point in putting off this particular project by debating in this thread, because I think the odds of finding someone to agree with you are the famous slim to none.

Just my thought.

Edit:

Another fact: Sometimes we get a little uptight when this is supposed to be all about having fun. Your proposed mod seems to most of us to be a little dumb (well maybe more than a little) but I'm pretty sure it's not the weirdest project that has shown up in these pages.

[fyrfytr1717]

Question for those who have done it. I got a factory extended idle switch and installed it. It works about 50% of the time. Usually it always works when I first turn the vehicle on, but if I've been driving for a while, it usually won't turn on.

I took the panel illumination wire and ground (orange and black) from the fog light pigtail, the dark blue power wire is spliced into the cigarette lighter/aux power circuit which is where my FSM says the oringal switch goes. And then I cut back the sheath of gray wire but didn't snip the wire, and just soldered the activation wire directly to that. do people usually just cut the gray #12 pin wire under the hood, and butt connect it to the lead coming from the switch?

Sounds to me like one of your connections is loose, either on the ground side of the switch, or the PCM side of the switch:

If it was the Orange wire, the switch's panel light wouldn't work correctly but it would have no effect on idle operation.
If it was the Dark Blue/White wire, the indicator light wouldn't work correctly but it would have no effect on idle operation.
If it is the Grey (Idle Actuator) wire, your idle will not work correctly but the switch lighting should be fine.
If it is the Black (Ground) wire, the idle, panel light, and indicator light should all be having issues at the same time.

It shouldn't matter how you make your connection to A12 so long as it's a good connection. The Grey wire is not connected to anything at the other end so it doesn't matter if you splice it, cut it, tap it, or any other method. I used a wire tap with a bullet connector myself, probably the least reliable option on such a small gauge wire.

Unless your '99 FSM is somehow different than mine, I don't believe that the switch indicator light power source (DB/WT) is shared with either the cigarette lighter power or the auxiliary power outlet. Both outlets initially receive power from BATT A7, but the cigarette lighter power passes through a relay which is kicked on by RUN-ACC A31. This means if you connected it to the cigarette lighter power source (Red), the indicator light would work in the RUN or ACC positions. If you connected it to the auxiliary power outlet (Red/Light Blue), the indicator light would work all the time as the auxiliary outlet is a fused B+ connection and is always hot. The intended power wire (Dark Blue/White) is powered by RUN A22 which is only hot with the ignition in the RUN position. Extended idle operation should not be affected either way, but you could get a false indicator light with the Extended Idle switch in the "On" position and the ignition switch in any position other than RUN.

[kastein]

I would bet on it not causing much trouble... 1000rpm vs 750 is not a big deal for the torque converter. The clutch isn't engaged, the heat should mostly be going into the fluid, which gets cooled via the same fluid circuit as the rest of the tranny... if you are too worried about it put an aux cooler on the tranny line. I'm not even going to get into the religious debate of whether it should go before or after the radiator :)

[Begster]

Sounds to me like one of your connections is loose, either on the ground side of the switch, or the PCM side of the switch:

If it was the Orange wire, the switch's panel light wouldn't work correctly but it would have no effect on idle operation.
If it was the Dark Blue/White wire, the indicator light wouldn't work correctly but it would have no effect on idle operation.
If it is the Grey (Idle Actuator) wire, your idle will not work correctly but the switch lighting should be fine.
If it is the Black (Ground) wire, the idle, panel light, and indicator light should all be having issues at the same time.

That is a good troubleshooting run down, thanks.


It shouldn't matter how you make your connection to A12 so long as it's a good connection. The Grey wire is not connected to anything at the other end so it doesn't matter if you splice it, cut it, tap it, or any other method. I used a wire tap with a bullet connector myself, probably the least reliable option on such a small gauge wire.

Ya, I actually went through a few more pages of the thread, and saw where someone pointed it out that the wire just ended at the connector.


Unless your '99 FSM is somehow different than mine, I don't believe that the switch indicator light power source (DB/WT) is shared with either the cigarette lighter power or the auxiliary power outlet. Both outlets initially receive power from BATT A7, but the cigarette lighter power passes through a relay which is kicked on by RUN-ACC A31. This means if you connected it to the cigarette lighter power source (Red), the indicator light would work in the RUN or ACC positions. If you connected it to the auxiliary power outlet (Red/Light Blue), the indicator light would work all the time as the auxiliary outlet is a fused B+ connection and is always hot. The intended power wire (Dark Blue/White) is powered by RUN A22 which is only hot with the ignition in the RUN position. Extended idle operation should not be affected either way, but you could get a false indicator light with the Extended Idle switch in the "On" position and the ignition switch in any position other than RUN.

Ya, my bad, I don't know why I saw cigarette lighter. I removed my cigaraette lighter and put a second power outlet in its place the same time I did the idle switch, so i got them mixed up. My wire is indeed tapped into the DB/WT wire going to the heater controls. I soldered the wires there, so I don't think there is a bad connection, but I haven't taken it apart again to check. I know the connection on the gray A12 wire is good.

One thing I did notice was one time I tried turning the switch on, I had the lights on, and it wouldn't work. The switch would be back light, but the yellow indicator light was not on. Once I turned the lights off, the yellow indicator light turned on, but it still did not raise the idle.

[moparjim1987]

just did this mod on my 97 last night, works great. cant wait to try out the winch with the higher idle now....or lights.....or anything else for that matter.

[badron]

I've suspected for a long time that most of the people who are members of this forum are less than competent and the negative responses to your proposed idle kick-up while in gear finally confirm that.
===============================================
He asked the question. We gave our answers. That's how it works around here. Or maybe we should put in the question "only people that agree with me need reply"?

[Pelican]

I think you missed my feeble attempt at sarcasm....

I assure you that I wouldn't waste my dollars on a membership every several years if I wasn't amazed at the depth of knowledge and ingenuity that shows up on the forum on a daily basis.

[fyrfytr1717]

One thing I did notice was one time I tried turning the switch on, I had the lights on, and it wouldn't work. The switch would be back light, but the yellow indicator light was not on. Once I turned the lights off, the yellow indicator light turned on, but it still did not raise the idle.

Now this sounds like a problem with having some of the pins switched. The operation of the fog light switch is based upon the position of your headlight/high beam switch and it sounds as if that is somehow affecting your high idle switch. Check the microscopic little numbers stamped inside the connector socket on the back of the switch to make sure you're actually hooked up to the right pins.

I'm sure you probably already saw it, but here is my original post laying out the pin-outs from back on page 10:

http://www.naxja.org/forum/showpost.php?p=244272197&postcount=149

[ReverendOD]

I've suspected for a long time that most of the people who are members of this forum are less than competent and the negative responses to your proposed idle kick-up while in gear finally confirm that.
===============================================
He asked the question. We gave our answers. That's how it works around here. Or maybe we should put in the question "only people that agree with me need reply"?


I hear ya. Main reason i ask is because like on our farm truck we idle around the property line sometimes at night to check fences, equiptment ect and run alot of lights so kicking up the idle speed is critical. A few hundred rpm lets us pay attention to what were looking at and not on working the throttle when the truck hits a rut or small incline.

1200rpm lets us just putter around without touching the throttle.

[badron]

so kicking up the idle speed is critical.
============================
I want to get it to work on my stick. With my deep gearing I can idle over most things. But it's so SLOW and to touch the gas almost always starts the wheels spining. The Eidle will give me a little extra speed without over doing it.

[Begster]

so kicking up the idle speed is critical.
============================
I want to get it to work on my stick. With my deep gearing I can idle over most things. But it's so SLOW and to touch the gas almost always starts the wheels spining. The Eidle will give me a little extra speed without over doing it.

Hand throttle.

A bunch of the guys in my old club who had sticks had hand throttles.


fyrfytr1717: thanks a lot. I somehow managed to reverse the orange and black wires. I will say that while attempting to put the wires to the correct configuration, there is a certain configuration that will turn the dash lights on when you hit the ext. idle switch. Everything works now.

[fyrfytr1717]

Sweet, glad to hear it's working now! The Orange and Black are easy to switch because they are mirror images of each other on the Fog and Idle switches. Throw in the fact that you're most likely using a pigtail other than the one intended for the switch and it gets even more confusing.

[Begster]

Yep, that was why I think I reversed them, because I pulled them out of the fog pigtail. The stupid part was I actually had the factory pigtail for the idle switch, and some amount of wire too, but I believe I jumped the gun and pulled the wires out before I made note of which ones went where.

[badron]

Hand throttle.

A bunch of the guys in my old club who had sticks had hand throttles.
===================================
So simple an answer. I must becoming a gismo geek to over look it. That way I can have any RPM/speed I want! Thanks again.

[ReverendOD]

Yeah without the option to manually set the idle speed thats is an awesome option. Getting around the NSS may not be a big deal but bypassing the 0mph might be?

[jeepcomj]

any way I can make my '98 4.0 5 speed do this?


I didn't have a wire in pin 12, but I just converted the xj from auto '97 to manual '98 wiring and everything, so I pulled the wire and pin from it.

What else do I have to do to emulate the park/neutral circuit?

-Pat

[Ewen91]

i too have a 98 cherokee 5-speed original harness, but i have upgraded the harness with a pin and wire comming from the pin 12. I ground it but nothing happens. what else is needed to make it work on a 5-speed?

[jeepcomj]

alot is needed, apparently.

the ecu doesn't use that pin. I even bypassed the clutch safety in hopes that the ECU would think it's in neutral.

but, when I put the automatic ECU in with the bypass, it worked...but threw check engine codes because there is no transmission.

[kastein]

I haven't verified that this will work, but you can try installing an auto ECU for your year and wiring in an auto TCU for a 97 (must be a 97), then installing 270-1000 ohm 1 watt power resistors on each solenoid drive wire to ground.

You may need to add a significant amount of wiring to a stock manual XJ to get the TCU in there, however. Probably not worth the effort. I would install a hand throttle instead.

Was the extended idle ever available factory on standards? I would think not, because there is the distinct possibility of the vehicle running away, or someone stealing it, neither of which is something the police really like.

[casm]

alot is needed, apparently.

the ecu doesn't use that pin. I even bypassed the clutch safety in hopes that the ECU would think it's in neutral.

but, when I put the automatic ECU in with the bypass, it worked...but threw check engine codes because there is no transmission.

Just to clarify: when you say that you swapped in the ECU for the automatic, are you referring to the main ECU or the transmission controller (TCU)?

I'm not clear on what if any sampling the ECU would do of the TCU to determine gear position on the AW4 - my gut feeling is that for extended idle operation it would only check the state of the NSS as reported by the TCU and use that as a go/no-go condition to kick in the extended idle (or not, as the case may be). Where it makes sense to me for it to operate in this way is that it shouldn't care which gear it's in, just that it's in park or neutral, so sampling the actual lever position wouldn't seem necessary.

This has me wondering if what's really needed is an NSS simulator that can feed the ECU with a bogus signal. Of course, that's based on the assumption that the ECU firmware for a manual-transmission XJ has the capability to do that - and even if it has that capability, if it's active when a manual transmission (and hence no TCU) is installed.

It might be worth picking up a TCU and NSS and seeing what the options are for installing them in a manual-transmission model. My experience with manual-transmission XJs is very limited at best, so this may be way more work than the end result would be worth.

Late edit: I need to learn to type faster than Kastein :D

[kastein]

Just to clarify: when you say that you swapped in the ECU for the automatic, are you referring to the main ECU or the transmission controller (TCU)?

I'm not clear on what if any sampling the ECU would do of the TCU to determine gear position on the AW4 - my gut feeling is that for extended idle operation it would only check the state of the NSS as reported by the TCU and use that as a go/no-go condition to kick in the extended idle (or not, as the case may be). Where it makes sense to me for it to operate in this way is that it shouldn't care which gear it's in, just that it's in park or neutral, so sampling the actual lever position wouldn't seem necessary.

This has me wondering if what's really needed is an NSS simulator that can feed the ECU with a bogus signal. Of course, that's based on the assumption that the ECU firmware for a manual-transmission XJ has the capability to do that - and even if it has that capability, if it's active when a manual transmission (and hence no TCU) is installed.

It might be worth picking up a TCU and NSS and seeing what the options are for installing them in a manual-transmission model. My experience with manual-transmission XJs is very limited at best, so this may be way more work than the end result would be worth.

Late edit: I need to learn to type faster than Kastein :D
Just an NSS simulator will work great while it's idling in P/N, but the TCU will get extremely unhappy about the fact that it's got no solenoids and no output speed sensor (thus the dummy load resistors) and if it's a 98 or later TCU will also get unhappy when the transmission doesn't shift as it expected it to (speed sensor signals) thus the 97 TCU idea. I'm also not certain about putting a TCU into an MT XJ, I think you'll at least need the ECU to be from an AT XJ for it to even bother checking for its presence.

[casm]

Just an NSS simulator will work great while it's idling in P/N, but the TCU will get extremely unhappy about the fact that it's got no solenoids and no output speed sensor (thus the dummy load resistors) and if it's a 98 or later TCU will also get unhappy when the transmission doesn't shift as it expected it to (speed sensor signals) thus the 97 TCU idea.

Good points. I'd completely forgotten about the solenoids & speed sensor.

I'm also not certain about putting a TCU into an MT XJ, I think you'll at least need the ECU to be from an AT XJ for it to even bother checking for its presence.

One more item to add to the list of things to check if I can ever get my hands on ECU firmware for the XJ. It's almost at the point where I'm halfway tempted to send ECUs for a few different years out to someone with better dumping equipment than I have access to and see what comes back.

[kastein]

Good points. I'd completely forgotten about the solenoids & speed sensor.



One more item to add to the list of things to check if I can ever get my hands on ECU firmware for the XJ. It's almost at the point where I'm halfway tempted to send ECUs for a few different years out to someone with better dumping equipment than I have access to and see what comes back.
I pried a '99 open to take a look inside it, as I recall it has an MC68k series processor with the batwings on it, and firmware is stored in a run of the mill Intel 28Fxxxx series flash chip. One of these decades, I'll get around to messing with it...

[jeepcomj]

I installed an ECU. if I had meant TCU, I would have said TCU.


I can tell you now that you will need TONS of wiring on a 5 speed to even make it possible to pop a TCU in there. there are no connectors for it, there are no mounts for the TCU under the dash, above the gas pedal, where it is located from factory. there is no wiring for it.

so, your deduction that the TCU is needed plus the aw4 NSS is probably correct. above that, though...a 5 speed ECU throws a CEL in an aw4 xj (tested this on my room mate's '97), and it won't shift. that tells me that the 5 speed ECU simply isn't capable.


you'd be better off making an adjustable voltage regulator/resistor to the IAC actuator/sensor. that's all the ECU does is adjust that to bump the idle.

hand throttles are for idiots. you bump it, you're screwed. there's no way to make it be disengage-able, save for disconnecting it when you're not on the trails. at least with an idle switch you could have an "arm" switch so it can't be accidently bumped.

[kastein]

I installed an ECU. if I had meant TCU, I would have said TCU.


I can tell you now that you will need TONS of wiring on a 5 speed to even make it possible to pop a TCU in there. there are no connectors for it, there are no mounts for the TCU under the dash, above the gas pedal, where it is located from factory. there is no wiring for it.

so, your deduction that the TCU is needed plus the aw4 NSS is probably correct. above that, though...a 5 speed ECU throws a CEL in an aw4 xj (tested this on my room mate's '97), and it won't shift. that tells me that the 5 speed ECU simply isn't capable.


you'd be better off making an adjustable voltage regulator/resistor to the IAC actuator/sensor. that's all the ECU does is adjust that to bump the idle.

hand throttles are for idiots. you bump it, you're screwed. there's no way to make it be disengage-able, save for disconnecting it when you're not on the trails. at least with an idle switch you could have an "arm" switch so it can't be accidently bumped.
I'm not sure you can do that with the IAC, it is a bipolar 2 phase stepper motor on 91+ XJs. Considered a way to do this but it's really not that easy, in effect it would end up being an electronic hand throttle even if it was possible - the ECU implements extended idle by watching the signal from the CPS and adjusting the idle air supply with the IAC to get 1000+rpm instead of 750, unless you somehow fooled it into thinking the engine is turning slower than it is, the idle control will no longer be closed loop... i.e. it'll be just a different more complicated hand throttle. The problem in fooling the ECU into thinking the engine is spinning slower than it really is is that it will go haywire trying to control fuel/ignition/timing and it's fairly complicated to do.

[casm]

I pried a '99 open to take a look inside it, as I recall it has an MC68k series processor with the batwings on it, and firmware is stored in a run of the mill Intel 28Fxxxx series flash chip. One of these decades, I'll get around to messing with it...

That's a lot further along than I've got with it - the junkyards around here want stupid money for working ECUs, and I just can't put the cash into this project at this time. Good to know it looks fairly normal so far, though; the real WTF will be how to extract the firmware. Could be easy, could be a PITA.

Anyway, food for thought. I'll quit hijacking the thread now.

[kastein]

The biggest difficulty for me would be reverse engineering the I/O hardware and also figuring out the address map. Pulling the ROM and dumping it is pretty easy when all is said and done.

I pay approx $50 for ECUs up here. I got the '99 one for like $10 at a part-out because I also bought the entire drivetrain, the radiator, and portions of the interior as well as the ACM and TCU.

[casm]

The biggest difficulty for me would be reverse engineering the I/O hardware and also figuring out the address map. Pulling the ROM and dumping it is pretty easy when all is said and done.

Agreed on both counts - but given that it's 68K-based, this may not be a total nightmare. Assuming that it's a vanilla 68K and there's not some horrible MCU or similar in use as an anti-piracy measure, it should be possible to dump the firmware, write a skeleton driver for MAME or MESS' 68K core, run the firmware in debug mode, see where it tries to read and write from, and go from there.

Note that I'm not saying this is necessarily the best approach, but should at least give a running head start at it.

I pay approx $50 for ECUs up here. I got the '99 one for like $10 at a part-out because I also bought the entire drivetrain, the radiator, and portions of the interior as well as the ACM and TCU.

$200-$300 is about the going rate around here for 'tested' ECUs; by 'tested', what they really mean is, "we turned the key and it started". Right now, though, I can't even free up $50 for this with inspection-grade maintenance looming and the other projects I've got in mind.

[kastein]

Agreed on both counts - but given that it's 68K-based, this may not be a total nightmare. Assuming that it's a vanilla 68K and there's not some horrible MCU or similar in use as an anti-piracy measure, it should be possible to dump the firmware, write a skeleton driver for MAME or MESS' 68K core, run the firmware in debug mode, see where it tries to read and write from, and go from there.

Note that I'm not saying this is necessarily the best approach, but should at least give a running head start at it.



$200-$300 is about the going rate around here for 'tested' ECUs; by 'tested', what they really mean is, "we turned the key and it started". Right now, though, I can't even free up $50 for this with the other projects I've got in mind.
Yeah, my thought was to desolder the MCU (it looked like an actual microprocessor, not an MCU actually - the firmware is external and in a standard flash chip so there should not be any protection on it) and cycle through all the addresses while watching the chipselect pin status on any bus-connected chips. Should give a full map with no difficulty. The chip had the motorola batwings on it, so I think it should be no problem... I just don't know 68k assembly yet. The real difficulty is that most of the I/O chips appeared to have custom chrysler part numbers on them, which makes it a real bear to look up datasheets.

Agreed on the ECU cost, stuff gets expensive.

Anyone in Mass/CT/RI/southern VT or NH have a 97+ stock manual XJ, preferably a 98 or later, and a spare ECU that is for the proper year but from an auto? I would like to try the 97 TCU, proper year AT ECU, and dummy load resistor approach but don't have a stock M/T late model XJ to play with.

If it works, you get working extended idle :thumbup:

[casm]

Yeah, my thought was to desolder the MCU (it looked like an actual microprocessor, not an MCU actually - the firmware is external and in a standard flash chip so there should not be any protection on it)

Understood that it's a 'real' 68K as opposed to an MCU. The reason I mentioned the MCU, however, was because it wasn't uncommon for them to be used as separate protection devices in some applications, notably arcade games. I have some (now-distant) past experience with them in that context, so was just mentioning them as a possible hurdle. Apologies if it sounded like I was confusing CPU and MCU.

and cycle through all the addresses while watching the chipselect pin status on any bus-connected chips. Should give a full map with no difficulty. The chip had the motorola batwings on it, so I think it should be no problem... I just don't know 68k assembly yet.

The cycle-through approach would work, no arguments there. I'd still like to grab a firmware dump in addition to that, though - one reason being that (once the memory map is known) it could conceivably be run in emulation to testbed modifications before pushing them out to an ECU.

FWIW, I used to be decent with 68K assembly - right up to 1995 when I replaced my Atari ST with a PC and pretty much never touched it again. I can generally kind-of sort-of muddle my way through it now, but years of disuse on my behalf probably puts me on about the same footing.

The real difficulty is that most of the I/O chips appeared to have custom chrysler part numbers on them, which makes it a real bear to look up datasheets.

Hm, bugger. I may be being paranoid (my experience with ECUs is extremely limited, so the parallels I'm drawing with stuff I already know may not be applicable here), but this is setting off my 'here be protection' radar.

By any chance have you got photos of those ICs? I'd be almost willing to bet that they're off-the-shelf items from a third party, possibly modified to order, and re-silkscreened with Chrysler identifying marks.

[kastein]

Nope, unfortunately I don't :(

I am nearly 2000 miles from my pile of XJ electronics hacking supplies.

They did appear to be standard ICs though, most of them had ST/Linear/Phillips/NXP logos but Chrysler part numbers. Chrysler really pisses me off that way, they get standard chips but order so many that they can wrap the manufacturer around their little finger and get them to print custom part numbers on them and never release datasheets for them, ever, for any reason. It's a severe pain in the ass when reverse engineering their stuff.

[casm]

Nope, unfortunately I don't :(

I am nearly 2000 miles from my pile of XJ electronics hacking supplies.

Hm, OK. I'll make some enquiries and see if I can't figure out a way to get an ECU to someone with the appropriate equipment. I know I don't have it ;)

They did appear to be standard ICs though, most of them had ST/Linear/Phillips/NXP logos but Chrysler part numbers.

Makes perfect sense. More:

Chrysler really pisses me off that way, they get standard chips but order so many that they can wrap the manufacturer around their little finger and get them to print custom part numbers on them and never release datasheets for them, ever, for any reason. It's a severe pain in the ass when reverse engineering their stuff.

One of my favourites in that department were the 50,000,000 Z80 clones made by the Soviets and Chinese. You'd think that they'd just copy them on a one-to-one basis, but, no, they'd do stupid things like modify, remove, or add instructions for no apparent reason - then patch Western software to run on their hacked-up hardware.

[the_big_h]

Seems to me that rather than reverse-engineer the entire ECU (which I agree is an interesting project in itself), it would be easier to design our own idle speed controller. The IAC motor is a 2-phase stepper - simple enough. Just unplug the IAC motor from the ECU, and plug it into a new idle speed controller. The new idle speed controller would need to know engine RPM (or calculate it from ignition pulses, or CPS pulses, or tach pulses, or whatever), and output the appropriate steps to the IAC motor to maintain desired revs setpoint. This revs setpoint could be selected with another input (from a switch), or even fully adjustable (with a pot or encoder).
I think it could be implemented on something as small as a 12F629 or 12F675, with a dual h-bridge driver chip, without too much difficulty.
Not sure if the ECU would get PO'd and throw codes about not being able to control the idle speed. I know it doesn't care too much - I disconnected my IAC motor to test a spare I had, it didn't throw any codes.
I've thought about doing this (even without a fast idle option) in order to give the IAC motor some more authority - so I can let the clutch out without having to step on the gas.

[kastein]

You could probably do that... I'm personally in the "anti-PIC bigot" group, I hate only having 35 instructions, but it's a theoretically simple design so you could probably put it in one of those MCUs. On 96 and earlier rigs the tach signal is (as far as I know) a pulse train going to the gauge cluster, that should be pretty easy to deal with. On 97 and later you would need to read the current RPM value off the CCD bus (see http://www.kolumbus.fi/juha.niinikoski/CCD_bus/ccd_display.htm) and use that to make your decisions. You also would probably have to do something about keeping the ECU from complaining on 96, 97, or 98 and later XJs, I'm not sure if or when IAC short/open/functionality tests were added but I'd put money on it being one of those years.

[praetorian]

Why not just use an adjustable hand throttle?

[jeepcomj]

because they're not as cool, and easier to bump.


I sold the 5 speed, and am doing this with a '99 conversion on my '87 mj.

[fyrfytr1717]

Wow, this thread got way hi-tech over the past couple of weeks. I'm totally lost, good luck guys!

[4WDlifeform]

I spent the better part of the day searching this one to death, even on other forums. FINALLY I found this thread with pics! So, thanks to the OP on this!!

NOW, however, on page 16 of this thread, it is FINALLY determined that this can NOT go on a 5-speed. I, have a 5 speed.... :banghead:

I am going to find a way to make this happen, cause I want this dearly. Hell, maybe I can come up with something that can get it up closer to 1,500revs. That would be more helpful!

Before I burn my brain on this anymore, is there ANYONE who has successfully installed this to a 5-speed, 97+, 4.0???

[Ewen91]

I reguards to the 5-speed extended Idle I still want to know myself.

98 XJ

ps. already have hacked the gray pin 12 and is out in the open ready for the next step.