dave1123

it seems many guys have discovered the PCM cover screws are too long resulting in them shorting out. If that is your problem, it's an easy fix, just shorter screws. Loosen them up about 3 or 4 turns and if the engine doesn't stall any more, that was your problem also.

Auger

I just took out the PCM, cleaned all the connectors and made some plastic washers for the screws. Then I used 4 regular 3/16" washers and one 3/16" lock washer for a total increase of 1/4".
Checked the battery with Ohmmeter and read 12.14v which is about right.

Cranked the engine over, let it run and it idled at 1000rpm for just about a minute and immediately stalled and died.

Auger

I think I am going to do the same thing. I'll buy three and if I get one that works on the first try I will still have 2 for later crises.

Auger

Can I use a 1998 ZJ ECU? What about year 2000? I know body has changed but my local UPAP lists 1993 to 2000

LiamLikeNeeson

Talk to a jeep mechanic about that because I'm not sure. I don't want to give you bad advice and you go and spend $125 on something that won't work.

Auger

Idle Air Control valve - INSTALLED NOV 4
Crankshaft Position Sensor - INSTALLED NOV 14
Spark Plugs Champion Copper - INSTALLED NOV 14

MAP Sensor - $68.79 Rockauto.com MOPAR part. INSTALLED NOV 23
Bosch Spark Plug Wires - $26.79 Rockauto.com INSTALLED NOV 20
Bosch Upstream O2 Sensor - $24.69 Rockauto.com INSTALLED NOV 23
Bosch Downstream O2 Sensor - $27.79 Rockauto.com INSTALLED NOV 23
Air Intake Charge Temperature Sensor - $15.63 Rockauto.com INSTALLED NOV 23
Throttle Position Sensor - $40.79 Rockauto.com INSTALLED NOV 23

...still doesn't stay on more than 55 seconds. /kicksrock

HAS to be the frigging computer? I buy a new one then gotta just buy a deck of them to make sure it works? Such a headache. Its annoying if this really is the end all be all problem solver. Im willing to buy a few ECU from the junkyard to throw in it but after that it is going to be $4000 off my next Jeep. If it does work, I totally have about 200k miles worth of new parts =)

dave1123

Backing off on this, I think you were right to suspect the IAC to start with. It sounds like the engine is running on cold startup mode at 1000, but then the PCM senses the engine heat and kicks it down to 750 idle, except it isn't kicking it down, but off. Yeah, PCM.

Oh....wait! Check the wiring harness to the IAC. You might have a broken wire!

boardutah

I followed the same route that you have. I put over $2k into my Jeep before I replaced the computer. I bought one off an old Jeep in the junk yard and 5 years later it's still running like a champ. Good luck

Auger

Thanks for all the help. It is a shame when I have to re-purchase brand new parts because they dont work. I'll have to check that IAC wiring harness but right now my Jeep has 5" of snow on it and I am inclined right now to sit inside, drink coffee, and smoke herb.

Auger

Happier Times

Figured I would post a picture of the Jeep when it was running strong and happy.