OBD I extended idle thread

Has anyone done this extended idle mod on their OBD I xj, I went through ALL the pages of the OBD II mod but have not yet confirmed that anyone has done it quite as easily as that on pre 96's. Has anyone done this? Does anyone have clear, concise, non-ghetto directions for this awesome mod? I'm not really ressurecting an old thread because this was not covered adequately in the other thread. 5-90, Langer-1, GoJeep, all you electrical gurus, I'm calling for your help. This is a hugely useful mod that a lot of people could get a lot of use out of. Lets make this THE OBD I extended idle thread. Thanks guys.

I don't have my FSMs handy, but I think it's going to depend largely on what year you have. OBD-II ECUs seemed to have the Extended Idle function hardwired into them - and it's just a matter of adding the switch to turn it on and off. It may be more difficult on the OBD-I system because it wasn't there in the first place, methinks. I'd have to review wiring diagrams tho - any specific year I should check? I'll if I have an electronic copy.

Failing the easy electrical route, have you considered using a hand throttle with a friction lock? Not as elegant as the switch, but it may prove more useful (greater degrees of control)...

Yeah mine is a 93 Jon but want it to be useful for all of us OBD 1 ers out there, thanks for your quick reply as always.

tkjeeper said:

Yeah mine is a 93 Jon but want it to be useful for all of us OBD 1 ers out there, thanks for your quick reply as always.

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Eh - you brought my attention to it. I just don't recall seeing the "Extended Idle" circuit called out in OBD-I wiring diagrams - but that doesn't mean much...

I'm reasonably certain it appeared concurrent with OBD-II, but I can't say I'm 100% on that.

According to this thread,
http://www.naxja.org/forum/showthread.php?t=35197&page=2&highlight=extended+idle

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

I still have to do this on my 95. But you know that since you PM'd me

I don't see it in my 93 FSM, but it is in the 95 FSM which says it is only available on the police package. I'm not if the police version of the ECM is different or it's just whether the switch is installed. The test in the FSM is to ground pin 10 at the ECM and the idle should raise to about 1000 rpm.

How is the plug numbered for 95?

Is it numbered with 1 on the bottom, or the top?

I really haven't looked yet.....

Now I'm even more confused. Looking at the ECM pinouts, pin 10 in both the 93 FSM and the 95 FSM is labelled power steering sense which is supposed to raise the idle under high power steering load. Seems to me that all you'd have to do is tie into that switch and ground it.

Blaine B. said:

How is the plug numbered for 95?

Is it numbered with 1 on the bottom, or the top?

I really haven't looked yet.....

Click to expand...

Not sure as I don't know which end is up. Pin 10 according to the 95 FSM is violet. The 93 FSM says dark-blue with white stripe, or violet.

lawsoncl said:

I don't see it in my 93 FSM, but it is in the 95 FSM which says it is only available on the police package. I'm not if the police version of the ECM is different or it's just whether the switch is installed. The test in the FSM is to ground pin 10 at the ECM and the idle should raise to about 1000 rpm.

Click to expand...

The switch was only in Police Package XJs, but the circuitry is apparently there - and simply requires a switch for activation. At least, that's the gist of all the modders that have done it.

Makes some small sense - to install the option, simply connect the switch. Probably cheaper to just make all PCMs have the option and wire it up as needed (Police Package XJ/X1)

My 95 FSM has the same thing. Looking at the diagram it shows pin 1 at the top left and pin 10 should be in the middle of that row as it ends at pin 20 across the top.

Good, nifty.

IIRC all of the harnesses are the same, so it shouldn't matter if its police package or not in terms of what wires are there.

Keep it coming guys, someone has had to have been successful with this mod to an earlier xj, I know jeepzz and 2001xj were successful with 97 plus but with all the heavy duty mods on this site this should be a piece of cake for these guys, keep the ideas coming. Thanks all. Lets get this solved once and for all and have a thread that everyone can use.

Lets go guys, any information is valuable here.

Be my guest

Tell us how it goes :roll:

big help Blaine, quality info. smart.

tkjeeper said:

Keep it coming guys, someone has had to have been successful with this mod to an earlier xj, I know jeepzz and 2001xj were successful with 97 plus but with all the heavy duty mods on this site this should be a piece of cake for these guys, keep the ideas coming. Thanks all. Lets get this solved once and for all and have a thread that everyone can use.

Click to expand...

I know my solution isnt EXACTLY what you are looking for. But here are a couple points that might back up my design. One, its completely removable. It doesnt mess with my ECM or any of my factory wires. Not that you cant just remove your wires...but Im just sayin its self contained. Two, its completely adjustable. I can have my idle be at 2000, 1800, 1980, whatever I want. Three, it uses an older vac. cruise unit, so its cheap.

I have had this hooked up since I made the thread... That was back in 8/--/05. It still works perfectly to this day. Fully automatic, fully adjustable, and hasnt failed once. I would have loved to figure out a way to make it adjustable on the fly...with a variable switch perhaps. But it just didnt seem feasable. This way, there is no danger of it EVER being able to go above your set RPM. No WOT activation...unless thats how you set it. haha. Flip on the switch, have it trigger however you want. Mine only functions when my york kicks on. York kicks on, idle goes to 2000, tank fills, york shuts off, idle goes right back down to normal. Like clockwork...everytime. Ive never posted vids of it working, or better pics since I didnt get much interest in it.

Ill post the link. If you go through all the links from the one that is already posted, you will find mine.

http://www.naxja.org/forum/showthread.php?t=64652&pp=15

Again, maybe alittle more work than just tapping into a couple wires from the computer, but I can have my idle set much higher than the couple hundred rpm bump you get from the switch mod or ext. idle feature from the factory. Which is what I wanted to run the york..

J.

I took a look at the PCM plug today.

I believe the PCM itself has the PIN. However the metal insert for Pin #10 on the PCM PLUG is not there. The hole is there, but there is no "female" insert nor wire.

What type of insert does this plug use? 5-90, how would you go about adding this single terminal to the plug?

Let me know, thanks!

Maybe pull apart a plug from a wreak and insert one from that? Most have a little tag that stops them pulling out so you have to depress that frist.

Blaine B. said:

I took a look at the PCM plug today.

I believe the PCM itself has the PIN. However the metal insert for Pin #10 on the PCM PLUG is not there. The hole is there, but there is no "female" insert nor wire.

What type of insert does this plug use? 5-90, how would you go about adding this single terminal to the plug?

Let me know, thanks!

Click to expand...

Essentially, what Marcus said. If it can be figured out just what sort of connector it is (MOLEX is common, as is Delphi Weatherpack and some .100" centres,) new connectors may be sourced as well, once you figure out where they can be had. I'd probably start with checking Mouser, NewarkInOne, and Allied Electronics (Allied does a good job with datasheets, so I'd probably start there, so I'd know what I'd need to measure.)