LT1-LT4 Modifications 1993-97 Gen II Small Block V8

ICM removal?

Old Jan 24, 2007 | 11:28 AM
  #1  
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Default ICM removal?

I am working on a 95 Formula that starts to stumble once the engine is warm. I just put on an MSD optispark thinking that was the problem, but the same thing happens. I believe that it is either the ICM or the coil. I want to get an MSD coil like THIS . My questions are: what does the ICM do and can I remove it?
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Old Jan 24, 2007 | 12:10 PM
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I had a similar problem. Go out at night in the complete dark and start your engine up and look under the hood and see if you see any light. Kinda sounds like one of your plug wires dried out and cracked and is arching off of a header tube
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Old Jan 24, 2007 | 12:27 PM
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Could be an arching wire as stated above or could be small vacuum leak. I had a friend who's T/A was doing the same thing and his vacuum line running to the EGR was dry rotted and leaking and no SES light was present. IF you still have EGR, give it a look as well as the many other vacuum lines learking on the intake.
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Old Jan 24, 2007 | 12:37 PM
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The only vacuum line I have goes to the FPR. The rest have been plugged. I dont think the spark plug wires are at fault, but that is something I did not think about. I am going to check those just to make sure it isnt the problem.

Also this car has a replacement MSD coil on it. I am thinking it might be the problem, my brother just bought one for his Mustang and it did the same thing right out of the box.
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Old Jan 24, 2007 | 02:49 PM
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Ive never had a problem outta my MSD replacement coil... I could be completely wrong, but I believe the ICM converts the commands from the PCM to a signal to control/fire the coil. This is based on the fact that the LTCC kit has a box that replaces the ICM and drives the coil packs.

You can convert to basically any coil by cutting the wires and adding your own terminals.
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Old Jan 24, 2007 | 03:47 PM
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That makes sense about what the ICM does. I have had one go out on a truck and it would not start. I will try another coil and some trouble shooting when I get home this weekend.

Thanks
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Old Jan 24, 2007 | 03:52 PM
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I've heard some problems with an MSD coil. If the wires check out, get a stock coil and try that
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Old Jan 24, 2007 | 07:59 PM
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The ICM hates heat.When mine started going out it would lose fire above 3000 rpm and backfire like crazy out the exhaust.Then it just **** the bed one day.But high heat will kill it.There is a mod you can do to get it away from the head with some sort of spacer,that helps the heat tranfer a little.But I couldnt say that yours is going out for sure.Do you have a freind with an lt1?Maybe you could switch it out to check it.Thats how I figured out my problem.Its hard to tell with the lt1 ignition system,it seems there is always something f...ing up.
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Old Jan 24, 2007 | 08:58 PM
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I have two of these dinosaurs so I am going to switch this weekend. I also have a leak in the radiator. This car loves attention and my wife hates this car.
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Old Jan 25, 2007 | 02:20 PM
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Originally Posted by Ru2slo_99
This car loves attention and my wife hates this car.
HAHAHA! My wife calls the TA my bitch... Seriously I had a friend call the house while I was out in the garage and ask where I was. She replied "He's out in the garage with his bitch." My buddy was floored, and said "And your allowing that?!?"

My wife does like the car alot more lately, as its been sitting for so long I dont go anywhere with it. She hates the car when its running, and loves it when I break something and tear it apart. At least that way Im home all the time.

Within a couple weeks she'll hate the car again and start complaining about the money Ive spent on it that she doesnt know about yet
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Old Jan 25, 2007 | 02:24 PM
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on a serious note, people space the ICM/Coil assembly off of the head with washers or whatever they can use. This allows air flow between it and the hot head, and makes them last longer.

My ICM's been relocated to a blower bracket since 42K miles, so Im still on the stocker. Which has about 90K on it now without a hitch. The stock Coil however, took a crap immediately after installing the MSD ignition box.
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Old Jan 25, 2007 | 03:22 PM
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Default My *****...

Originally Posted by Fire67
HAHAHA! My wife calls the TA my bitch... Seriously I had a friend call the house while I was out in the garage and ask where I was. She replied "He's out in the garage with his bitch." My buddy was floored, and said "And your allowing that?!?"

My wife does like the car alot more lately, as its been sitting for so long I dont go anywhere with it. She hates the car when its running, and loves it when I break something and tear it apart. At least that way Im home all the time.

Within a couple weeks she'll hate the car again and start complaining about the money Ive spent on it that she doesnt know about yet
LOL...sounds just like my wife..she calls mine my *****...
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