Quick question on the PCM

[e_clouser]

My 94 has been acting up. I have replaced everything I know to do i.e. the ground wire. Everything I do seems to help and the car makes it a little bit longer before it acts up again. Some one said the PCM could be bad. Will any MTX PCM work?

 

[Off Road SHO]

Yes the one out of your 92 will work but why don't you describe the the problem and symtoms a little better and maybe we could help you.

Tom

 

[Rockledge]

What are the codes you're getting?

http://www.shophoenixproject.com/eec/eec.htm

 

[rangerj]

As best I know "someone said it could be the PCM" is not a diagnostic procedure. That having been said, the following is a test procedure for an intermitent PCM problem. The PCM (ECU or das computer) is on the passenger side behind the glove box. With the engine running, selecter in park if automatic, or the selector in neutral if a standard shift (emergency brake on) tap on the computer with the handle of a screwdriver. If you can make the car "act up" at will, or run OK, by tapping on the case, then there is a problem in the computer. By tapping on the case you are simulating the "bumps in the road" and finding out if that is what is causing the malfunction. The test is not fool proof, but it has worked without fail for me.

If you cannot recreate the poor running condition by thumping on the computer, then look elsewhere for the problem, say the DIS system. (Search for the DIS tests and how to do them.)

 

[e_clouser]

SYmptoms..... car will run fine, then the CEL will come on but very dim. car will spit and sputter, run very rich and most of the time die. sometimes when i try to restart it the cooling fan and fuel pump will be running and the car will not start. sometimes it will start right back up with no problems. tried to pull codes, nothing, did not work... CEL stayed bright. no blinking.. Then the next time I got almost every code in the book... all my 60k's have been done i have even tried to use things off my 92 to keep from just buying new parts. like i said, i went on a 2 hour trip with it on the fourth of july with no problems, and just last night it started the same thing. I have checked all the grounds. When the car does run right, it runs strong, no issues.

 

[Bizzy]

The codes you're getting could be ones that have been stored up for awhile. What I'd suggest doing is start the codes running just like you've done in the past and pull the jumper out while it's still running them. That will clear the codes. Then drive the car around for 40-50 miles and then re-run your codes so you know you're getting fresh ones.

The dim CEL light worries me since it should either be off or on and bright. There shouldn't be any in between, that screams short to ground to me.

Did all this just happen out of the blue or had work been performed and then this all started happening?

 

[e_clouser]

The codes you're getting could be ones that have been stored up for awhile. What I'd suggest doing is start the codes running just like you've done in the past and pull the jumper out while it's still running them. That will clear the codes. Then drive the car around for 40-50 miles and then re-run your codes so you know you're getting fresh ones.

The dim CEL light worries me since it should either be off or on and bright. There shouldn't be any in between, that screams short to ground to me.

Did all this just happen out of the blue or had work been performed and then this all started happening?

The codes were cleared when I did my 60k about 2000 miles ago. Tranny was replaced about 1000 miles ago. Yes it all happened out of the blue. I was headed down the road and the CEL came on dim, then bright, then dim again. Car shut off, and would not restart. I was told to check the ground wires. I pulled all grounds and cleaned them. Then was told to try another PCM. I am now gonna go try to beat my PCM to see if I can get it to act up. I will say that when the CEL is dim the car, if it stays running, runs very very rich. When the light is off the car screams. I am at a total loss and ready to sell the thing soon. Ok maybe not but this is getting on my nerves now... will post what I find in a bit.

 

[e_clouser]

ok I beat on my PCM with the car running, no difference. Once it dropped in rpm but no CEL. Pulled codes again, got one 111 so this tells me system pass.

PCM seems good, grounds seem fine, what is next to replace on the money pit?

 

[FoeSho]

Sounds like a ground issue.

 

[e_clouser]

Car fixed. The hypertech chip on the back of my PCM was loose. Pushed it back in and wow it runs again and good. Hopefully she will stay running now. Thanks for all the help