removing icm bracket

How do you get this thing off? I had the rear bolt out and all the nuts/bolt on the front off bit it wouldn't move at all.

Doesn't the rear have 2 bolts? I know the one long one with the ground wire attached to it, and then there's the nut behind that as well. I swear I think I remember there being 2 bigger bolts in the rear (front of engine).

What the heck is an ICM? Just curious

Maybe there should be an index of acronyms somewhere on this forum for dummies like me.

Ignition control module

Thanks for that, also I found the acronym list on this forum but ICM wasn't listed.

Steve

If you're looking at it from the passenger side, I could only see 2 points of attachment...the bolt on the left, and the bolt/nuts on the right. I put new oem coils and icm on and broke that ground wire in the process. I fixed it, and now the car runs really bad and reeks heavily of gas when running. Swapped one of the new coils out for old one, ran perfect for a mile or two then started acting up again. That ground wire checked out so I'm not sure what happened

There's three points of attachment. The big stud coming out of the head where the ground ring is, a small bolt at the front that threads into the tensioner assembly and the last one is on the other end of the ICM at the back and threads into the cylinder head on the same plane as the lower intake so the bolt head is facing kinda up and towards the back of the car a little instead of out the passenger side. It's easy to miss.
pull that main ICM harness off and make sure the female pins all look good. Occasionally you get some that are opened up and too loose then you can kinda carefully close them back up with a needle or something. I haven't encountered that problem myself but James has and it's worth checking since you're there having issues.

I'd recheck that Ground my friend. Was it green on the inside at all? Those little wires have a tendency to corrode and turn green. You'd never know it until you have to move it one day. You might just have to replace that little section if wire. The coil swap may have just been a coincidental thing.

I've also had to repair many a wire off the front of the ICM where it makes that nasty turn. I personally had a bad wire inside that conduit as well. All it takes sometimes is for you to move it....

Well, I broke the ground off right at the ring terminal. There was a very small amount of green on the end of the wire. I stripped about 2 inches of insulation off and crimped it with another section of wire with a new ring terminal on the other end and that's how I took care of that. I am pretty sure the ground is okay.

I started swapping the coils out again after work today. I was running with 1 old coil and 2 "new" coils and it was running bad...with 2 old coils and 1 "new" coil, it still ran bad...once I took that last coil off, and put the remaining old one back on, the car ran fine. I noticed the last coil I took off, the colored area on bottom was gray instead of yellow like the other 2 new ones. Relevance?

Anyway, I say "new" because they are sold as a kit on Ebay...three coils, the ICM and the bracket. The coils are "factory seconds" ACDelcos but the company sells a ton of them and has good feedback. I already contacted them about possibly having a bad coil, they are currently awaiting my response as far as how I want to proceed.

My next question is, with the coils OFF the vehicle, is there any way to test them with a multimeter? I could have sworn there was a FAQ on here about it but I can't find it.

The color on the bottom of the coil pack does matter. Supercharged are supposed to be blue and are higher output. Grey is n/a. I don't know what yellow is because I haven't seen it.
I would assume that grey coils would still work on a s/c motor but I haven't personally verified

I really hate how GM does their part numbers sometimes.

The two yellow bottomed ones are: 10468391
The grey bottomed one is: 10422929 (or 10422928, I can't really tell) but I can't find any info on those numbers anyway.

The OEM coil for the 95 S/C is supposed to be an ACDELCO D555 (which 10468391 is an interchange for). The D576 (blue buttoms) aren't listed as a required OEM replacement for my car. I actually posted this question a while back here:

https://rivperformance.editboard.com/t11165-which-ignition-coil-part-number-should-i-use

I *THINK* the old coils on my car had yellow bottoms as well. I know the coils for the N/A cars have lower voltage correct? That would probably explain why my car ran horribly with the "grey bottomed" coil installed.

I really can't be certain but i'd think the greys would idle just fine. I'd expect problems like misfires would possibly arise under boost conditions where the hotter spark is more critical. James said that GM blue coils are not available anymore. He snags them from junkyards and stocks up. I don't know how the part numbers interchange with aftermaket but yeah I GM part numbers suck.

Well with that grey bottomed coil on, the car WOULD run and idle...but I could tell it was missing or not running right, it was a very audible difference. It would stutter and hesitate when giving it gas, acted more like it was missing, and there was a very noticeable gas smell. VERY noticeable.

You're right Bill the yellows would have been stock to your car. I added the 'blue' coils to my Series I L67 when I started modding it heavily. If you can pick up a set of blues they would probably more helpful than most other coils. I know someone who has a stockpile of them too if you're interested.

Z-type wrote:

You're right Bill the yellows would have been stock to your car. I added the 'blue' coils to my Series I L67 when I started modding it heavily. If you can pick up a set of blues they would probably more helpful than most other coils. I know someone who has a stockpile of them too if you're interested.

I appreciate the offer, but my car will be 100% stock so I don't think the blue ones will do me much good. I just got the 3 coils, plus the ICM as a set to replace parts with 200k miles...better safe than sorry. I will be contacting the seller to swap out the grey one he sent me for another yellow, hopefully that'll work!

The seller is sending me another yellow bottomed coil and told me to just keep the grey bottomed one. Does anyone know what application this coil is used for specifically? I can't find anything on its part number (10422929 or 10422928, I can't really tell) and would like to give it up so someone can put it to good use at least.