3800 Symptoms of a bad ICM (Ignition Control Module)?

[jk99gtp]

Anyone ever had to replace their ICM? If so, can you let me know what your symptoms were that made you think it was the culprit?

Thanks.

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[DaytonaPaceCar]

Yup. Mine would backfire and buck at anything over 10psi boost. I replaced the ICM, coils, wires, and plugs. I belive the ICM caused a BAD arch between posts on the coils. Burned the coils (posts) and the plug wires pretty bad. Actually blew two plug wires OFF the coils on 2&5.

 

[jk99gtp]

Thanks for the reply Justin,

My car is chugging/misfiring at idle (I can actually hear popping in the exhaust sometimes), and I can definitely rule out the plugs/wires, since I replaced those last week and everything was going well for about a week or so until this happened..

I'm hoping its just the coils, or the ICM...

 

[imported_Ron Vogel]

12secGTP had the same problems, IIRC it WAS the ICM.

 

[ThaLord]

I think 12secGTP had a problem with his cat.. I seem to recall being there.. while gutting it.. lol

 

[imported_Ron Vogel]

Originally posted by ThaLord@Jun 1 2005, 09:28 AM
I think 12secGTP had a problem with his cat.. I seem to recall being there.. while gutting it.. lol

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I know, but I think it was only part of the problem. After he gutted it he still had issues. I tried to do a search about it, but it came up empty. I think it goes back past when we had that one major server problem where we lost a bunch of posts.

 

[ThaLord]

maybe I'm wrong.. but I was sure it was the cat...

and.. we didn't have any server problems where we lost data.... we switched servers. and I ditched some data.. this was back in 2003 I think though...

John

 

[imported_Ron Vogel]

Yes, it was early 2003/late 2002 IIRC. He had the Dis-4 MSD unit on the car and was playing with it; aww hell...I'm going to PM him and straighten this out. My brain hurts trying to remember this stuff!

 

[jk99gtp]

Thanks guys,

I have a feeling it is the ICM also.

- I am throwing P1361 and P1362 codes, but after clearing them they don't come back. So not sure regarding this, but it does point to the ICM alittle...

- One second the car idles fine, the next second its hunting and misfiring/surging/bucking...

- Just by revving the motor at idle, I am getting misfires per the scantool. And its not dependant on any cylinder, as one minute it shows misfires on cylinder 3, then next it will show misfires on cylinders 1 and 5. Just to be safe I pulled a couple of plugs (To make sure I didn't chunk a piston), and they look fine...

I have some new coils, and a new ICM coming from the parts man himself Ed Morad this week, so if this doesnt fix it, I will start working my way towards the Cat (Thanks for the suggestion John). The only reason why I doubt the Cat right now, is because the downpipe is brand spanking new, but ya never know I guess!

Thanks,

Joel

 

[jk99gtp]

hmm..

Well I believe I figured out my issue, and it wasn't the coils or the ICM

After replacing the coils, and the ICM, it kept on hunting, misfiring, and I kept on throwing the P1361 and P1362 codes. I was about ready to give up, but I saw a green/yellow wire (covered with tape) that had must've melted itself on the header crossover, just hanging there...

So I spliced the melted part off, and then grounded it to one of the bolts that are on the boost bypass valve. I didn't have much wire to work with, and the only piece of metal I saw was connected to one of the boost bypass bolts...

Voila, car starts perfectly now and no more codes. I must've started the car like 10-15 times, and perfect each time...

Funny thing is, this wire had never given me a problem in the past (It's always been unhooked, or at least for what I can remember). I always thought this was a ground to the remote start I had, since it was hooked up to a piece of fabricated metal that was towards the back of the motor. I guess since it was touching the hot header it must've been wreaking havoc with the bundle of wires it was spliced into...

 

[syP]

before this problem...

how did ur car start up??? im wondering if this is my problem as well..

 

[jk99gtp]

Syp,

Not sure what you mean..

Do you mean how my car started up before it started to exhibit these problems?

If so, it started up perfectly normal..

I think the problems started to occur with that wire, because I had wrapped it around my EGR to move it out of the way of the headers. Then when I removed my EGR, the wire fell and must've been touching the headers and caused a short somewhere, hence the weird problems...

While I was having issues, the car would only buck, misfire, die, at low rpms (Under around 1500rpms) to idle. If I were to keep the rpms up, the car would drive perfectly fine...

Thanks!