PCM from working Jeep not working in other Jeep

OlTrustyYJ

New Member
Joined
Jul 5, 2024
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1
Location
Pennsylvania
Hello:

I have 2 1995 YJ 2.5 with 5 speed manual transmissions (and a 95 yj 2.5 with an automatic transmission).

My daily driver started intermittently chugging and few months ago. After all the normal replacements of Cap, rotor, fuel pump, etc, I narrowed it down to the PCM. My parts jeep, which now looks picked over like the thanksgiving turkey by Sunday, has been sitting for 4 years. last started 3 years ago. I took the PCM off it and on the daily driver and no start. Put the original back in and fired up. Same 828 part number.

Anyone have an idea why it wouldn't start with the spare PCM?

Pulled the cover off the spare and saw some cracks in the goo. other than that, all the capacitors are good.

Only thing I can think of is that the daily driver is a rio grande and the parts jeep is a regular wrangler, but the part is the same number.
 
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If they're the exact same part number, then they are the same part. There is no programming, all the different PCMs in the YJs are differentiated by part number only, so similar and same part numbers are the same. Sounds like the spare went bad while sitting, and bad in a different way than the original. If I read your post right, you have three 2.5 YJs? If so, grab the one out of the automatic and see if it works. I read it as you have 2 manuals and an automatic.
 
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As macho said, that one PCM is probably bad. I would do like he said and swap the auto pcm in. If it runs on that one, than that pretty much narrows down your issue.

When you swapped in the parts PCM, did the check engine light come on when you turn the key?