AW4 no shifty shift.

well i have been ..... FOR DAYS:helpme:!

90 aw4 4.0 d30/35 W/ABS will not shift out of 1st gear.

i have gone through everything in the system. there only a couple culprites left. http://www.transonline.com/transdigest/magazines/1997-10/Shift Pointers/index.html from this i come up with 2 off readings.

1. D3~ TPS Ground. should read .1volt or less. we have .8v
2. C9~ "Drive" selector position "shifter" should read BATT. voltage. we have .8v

http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm
tells how to bypass the ground for the tps. repeatively, also states to check over all the motor grounds."done" so we went from the firewall to terminal "B" on the tps as stated. came up with the same reading.

i may need a more in-depth explaination of this procedure.
i'll stop here an go over everything we've done.

TCU.
unplugged we get manual shift. "its electrical." checked the inline fuse. fuse at the block, tested for power. all good. Replaced TCU with a known working one. nothing;shift solinoids.
replaced and reading in spec "11-15," all 3. nothing

TPS.
tested, adjusted. no change. Replaced, readjusted. in spec. nothing

Throdle valve cable.
Checked and adjusted.nothing

NSS.
Removed, cleaned, reinstalled, adjusted.
http://www.go.jeep-xj.info/HowtoNSSrebuild.htm

Shift linkage.
checked and adjusted. nothing
Motor/Engion Grounds.
checked, added grounds to both just to be shure.nothing.

Now. refering back to the off reading on C9. i should have batt voltage with the shifter in drive. we don't. but we do get it with the shifter in the "3" slot.

is it possible to be so slightly out of adjustment on the NSS/shift linkage that it will start only in "P" and "N", nowhere else. still have lights in "R" and cause this specific problem?

I have no idea what to do about the D3 reading of .8v how do i get it down, keep the tps adjusted in spec, and get the correct reading? like i said before we bypassed it from the firewall to terminal "B" and i tried both harnesses just to be sure. the readings stay the same but the truck won't idle down below 2k. this im stumped on and could use some help to understand.

i know i'm going the right direction. i just cant seem to find the missing link.
plz plz:helpme:. were going nutz.

thx alot yall
Bronze.

Most likely a bad ground from the head to the firewall.

Don't worry about #1. 0.8 volts is fine for this purpose.

You have 2 porblems you need to address. The C9 voltage indicates a problem with the NSS switch. It is probably adjustment. It can't be a wiring porblem, since the voltage is correct in 3. Loosen the NSS clamp and rotate the sensor slightly until you get 12V in D. Then tighten the clamp and make sure all other switch voltages are correct in their respective shift positions.

Next fix that high idle problem. It is likely only a dirty IAC. This is not causing your shift problem, since there is no feedback to the AW4 of the actual RPM, it only knows about the throttle position and the throttle will be closed when the IAC is stuck open.

Bronzewyrm said:

1. D3~ TPS Ground. should read .1volt or less. we have .8v
2. C9~ "Drive" selector position "shifter" should read BATT. voltage. we have .8v

Now. refering back to the off reading on C9. i should have batt voltage with the shifter in drive. we don't. but we do get it with the shifter in the "3" slot.
is it possible to be so slightly out of adjustment on the NSS/shift linkage that it will start only in "P" and "N", nowhere else. still have lights in "R" and cause this specific problem?

the truck won't idle down below 2k. this im stumped on and could use some help to understand.


Bronze.

Click to expand...

I agree on the high idle being part of the issue. My '90 did this a few times until I fixed the high idle issue. has not done it since.

I think with mine while I was idling in gear (IE at the bank drive through) it got too hot since it was idling high and started acting up.
When mine did this I would end up running it to redline and it would shift at redline. it would need to go through all the gears and once in OD it shifted just fine after that. Until of course circumstances made it act up again.

Fixed the high idle which ended up being the TPS...CHECK IT mine had a bent arm and eventhough it was 'reading' the correct voltage it was not right. I replaced my IAC and cleaned the TB which did nothing for mine. So I would check them both. Mine has not acted up in 2+ months putting 200+ miles a week on it. (this also fixed my stalling issues)

i think theres a misunderstanding. there is only a high idle with the "B" terminal regrounded. or "bypassed" stright to the firewall. if wired throo the stock wireing it runs fine. just the .08v reading where it should be .1 or less.

today we adjusted the nss while in drive. we went on the adjustment, stop to stop. and could not get BATT voltage at c9.in drive. still only the .80v i think this is the source of the problem but im really stumped.

thx agin guies.
Bronze.

Bronzewyrm said:

i think theres a misunderstanding. there is only a high idle with the "B" terminal regrounded. or "bypassed" stright to the firewall. if wired throo the stock wireing it runs fine. just the .08v reading where it should be .1 or less..

Click to expand...

I agree with you. There is most definately some misunderstanding here. A reading of .08v is most certainly less than .1 volts. I believe you said in your original post that the reading was actually 0.8 volts. I earlier recommended that you ignore this and I stand by my position. This voltage is digital, meaning it is either on or off, high or low. It is not critacal, like the analog TPS signal voltage.

Bronzewyrm said:

today we adjusted the nss while in drive. we went on the adjustment, stop to stop. and could not get BATT voltage at c9.in drive.

Click to expand...

How did you adjust the NSS in drive and not get the BATT voltage at C9? I recommended you adjust the NSS in drive untill you get the 12 volts at C9. How could you think you adjusted it correctly in drive and still not get BATT at C9?

Bronzewyrm said:

still only the .80v i think this is the source of the problem but im really stumped..

Click to expand...

As I said before, give up on this one.

MoFo said:

I agree with you. There is most definately some misunderstanding here. A reading of .08v is most certainly less than .1 volts. I believe you said in your original post that the reading was actually 0.8 volts. I earlier recommended that you ignore this and I stand by my position. This voltage is digital, meaning it is either on or off, high or low. It is not critacal, like the analog TPS signal voltage.

How did you adjust the NSS in drive and not get the BATT voltage at C9? I recommended you adjust the NSS in drive untill you get the 12 volts at C9. How could you think you adjusted it correctly in drive and still not get BATT at C9?

As I said before, give up on this one.

Click to expand...

.8 volts for the tps ground is what im getting.

i admidtly dont know much about multi-meters. i have been feeling my way throo this the whol time.

so i ignored the tps ground. we pulled the adjustment nuts loose on the NSS.placed the trans in "D" we then hooked up the meter.key on. .8v. we Rotated the NSS back to its stoping point. nothing changed on the meter. so we rotated the other way with the nss adjustment until it stoped. we got no change on the meter what so ever. we get .8 volts. Batt voltage only shows in the "3" slot for c9.

wireing? :dunno:
bad nss?, diden't think it was possable.

p.s.~ OLD_MAN: i checked it. we also ran a new one from the BATT to the body and another from the batt to the motor. still nothing.

The most important thing you need to do is to get 12v to C9 of the TCU in Drive. In reading back through your post, I gather that you can never get 12v at C9, regardless of the shift selector positon or the switch adjustment position. Later in this thread you also said that you get 12v at C9 with the shifter in 3. Is this true? This statement would contradict the one above. Are you certain you had the positive meter probe in C9?

If you can never get 12v at C9 in drive, regardless of the switch adjustment position, and you get 12v at C9 in 3, you must have an internal problem with the NSS, such as a broken or mis-located brass wiper. You said earlier that you cleaned the NSS. Are you sure you got all the pieces back in the right place?

As a next check, before you remove the NSS again, I recommend you check for 12v at C8 with the shifter in 1-2. If 12v is present, this confirms the power to the NSS is present and the wiring to C8 is not damaged. If your reverse lights are still working, this would also confirm 12v to the NSS.

i appolgise. i dont mean to be confusing.

voltage at c8 is there and fine in 1-2. i know we got the nss back together right. it was really stright forward.

c9 we can only get batt voltage in the 3 but cannot get +/- of .8v in drive.

so still nss huh? can they go bad? i dident see anything that could go out while it was apart. the contacts were there, and the springs good. hmmmm.

You said you checked the grounds. Did you remove them and clean them or just gander at them? The dipstick tube stud grounds are super critical and were an issue when the Jeeps were new. Too much paint on the block, improperly crimped wire terminals etc.

I have adopted the habit of disconnecting all the sensor connectors in the engine bay, including the ones to the trans near the firewall, one by one, and cleaning them out with contact cleaner. Takes 10 minutes and has cured some issues for me.

The engine grounds and cleaning the sensor connectors are critical, especially on a RENIX engine. However, they have nothing to do with the problem of no 12v at C9. This is either a bad NSS or an open wire between the NSS and C9. We can rule out the open wire, since the voltage is there with the selector in 3, leaving only the NSS. I agree that it would be hard to get the switch back together wrong, but you could have pinched the wiper for the circuit and broken the end of it off. This would allow it to slide out of position. I think it is time to take the NSS apart again and have another look. We have a known bad state at C9 and need to take that to resolution before we start poking at other connectors. We can do that after the NSS output for Drive is correct, if there is still a problem.

Haven't read all the stuff here......but does the 90 model have the Power-Comfort switch? In my 88 there is a fuse in the fuse panel for that.

The fuse you mention is the 7.5 amp fuse which is inline to the 12v supply to the NSS. If the fuse was open, there would be no 12v from the NSS in any position and the reverse lights would not operate.

MoFo said:

The fuse you mention is the 7.5 amp fuse which is inline to the 12v supply to the NSS. If the fuse was open, there would be no 12v from the NSS in any position and the reverse lights would not operate.

Click to expand...

Are you refering to the fuse marked TRANS?

Don't know all about that...but when I was having my shifting problem, the PO had removed the fuse.

When I put it back in .....my Power-Comfort light in the switch came on and I could tell the difference somewhat in which mode it was in, whereas with the fuse out, the switch didn't seem to work.

I even read on here somewheres about that fuse needing to be there.

But Hey, I'm learning new stuff all the time here on this board.:lecture:

It mentions the 7.5 fuse in the transonline article on the first page.

Copied from the text from that article:
"In the chart you will see an asterisk next to the neutral-switch and comfort-switch checks. If battery voltage is not seen as in- dicated in the chart on both sensors, check for a blown 7.5-amp #13 fuse in the main fuse panel."

MoFo said:

The engine grounds and cleaning the sensor connectors are critical, especially on a RENIX engine. However, they have nothing to do with the problem of no 12v at C9. This is either a bad NSS or an open wire between the NSS and C9. We can rule out the open wire, since the voltage is there with the selector in 3, leaving only the NSS. I agree that it would be hard to get the switch back together wrong, but you could have pinched the wiper for the circuit and broken the end of it off. This would allow it to slide out of position. I think it is time to take the NSS apart again and have another look. We have a known bad state at C9 and need to take that to resolution before we start poking at other connectors. We can do that after the NSS output for Drive is correct, if there is still a problem.

Click to expand...

MoFo, is it possible that the voltage signal is not getting through one of the connectors for the NSS near the firewall/trans dipstick? That's why I posted my suggestion.On my 88 Arizona XJ those connectors were both full of corrosion.

Cruiser- The key here is that 12v is present at C9 with the shifter in 3. That means the connections to the NSS and from the NSS are good and also the supply voltage and fuse is good. That only leaves a problem inside the NSS.

Gotcha.

The D3 and C9 readings shouldn't cause it to not shift out of 1st. I think you might still have an NSS issue on the D signal though.

I would suspect the speed sensor is bad. That signal is on pin C3. For a 1990 it should have a 12-volt signal that gets grounded once per revolution by the sensor. The sensor itself is a magnetic switch that gets closed by a magnet on a rotor on the output shaft.

To test the tranny output speed sensor, use your meter to measure voltage between C3 and ground, with the TCU connected, ignition on, and engine not running. Chock the front wheels, jack up a rear tire, put the trans in neutral, xfer case in 2H. Now slowly spin the jacked up tire and you should see the voltage jumping between 12 (battery voltage) and near 0 (ground) volts once per driveshaft revolution.

If that looks good, suspect a bad trans computer. Its pretty rare but they can be bad.

There are TWO transmission fuses--the aforementioned 7.5 amp for the Power/Comfort switch circuit and the 10 AMP for powering the TCU--on your 90 the 10 amp fuse will be an inline on a yellow wire leading to the TCU.

There are TWO TYPES of AW4 solenoids, make sure you put the right solenoids in the right places.