Strange misfire/stalling especially under load issue

[Milford Cubicle II]

Well, I'm ok with dropping $150 for a reman'd PCM if that's the problem. Unfortunately I have almost no idea whatsoever how to test for a bad PCM. I've tried wiggling the harnesses and tapping on the case and nothing changed. I guess I could actually open up the computer and hope to see a burnt spot or something :dunno:

 

[kastein]

Not gonna help... they are sealed with silicone. Opening it will only make absolutely sure that if it isn't dead now, it will be the first time it rains, since resealing it will require an act of Congress.

BTW, as far as I know, the "remanufacturing" process on PCMs is "clean case, clean contacts with contact cleaner, half-assedly test to see if it works at all, slap new sticker on, sell to consumer." You're better off buying one (or two) with the same part number from your friendly local you-pull-it junkyard, and asking for the $5 warranty.

The PCM contains a fairly advanced embedded microcomputer, I've pulled a few 97 and later ones apart and they have an MC68k 32-bit microprocessor plus quite a variety of driver transistors, step motor controllers, voltage regulators, memory chips, etc etc. Haven't pried a '96, '95, or earlier one open yet though. The RENIX (90 and earlier) one I opened up was amazing, I haven't seen a board like that in years.

 

[Milford Cubicle II]

Actually my friend replaced his PCM on his 99' WJ with a reman and he actually called and asked what the re manufacturing process was and they said that they replaced all of the electronics inside including the flash memory. Basically everything but the case, and judging by how the thing looked I believed it, it looked brand spankin new. If I do replace it, I'll have to ask him which company that was and get one from them.

 

[5-Speed XJ]

i got mine figured out two bad injectors and a bad collent temp sender = many bad codes

 

[Eli Lilly]

I just spent forever chasing down a horrible hard-start, rough idle, stalling, surge problem and it ended up being a defective temperature sensor I installed a couple months ago. On my 95 I was able to unplug the sensor and the engine operated fine, then I ohmed the sensor and it was 600K, which is below zero degrees according to FSM. Swapped one out of my blown 93 and now no problems.

It was a PITA because you don't think to go back and retest new parts for failure. But now it's got a new IAC, TPS, CPS, IAT sensor, and MAP sensor.