In my quest to solve this low rpm stumble when warm problem i've been having, i've come across one cheap possible "fix" for it.
Placing a few washers between the ICM (i think its the ICM?) which currently is attached to the block with two bolts and thermal paste to conduct heat. Heres what doesn't make sense to me, or i flat out don't know whats going on.

The fact that there is thermal paste leads me to believe that GM intended for there to be heat passing from a hotter object to another object, and what i've heard from people suggesting this "mod" is that the ICM is getting heat soaked from the block and malfunctioning when it gets too hot. This seemed logical until i thought about it some more.

This would mean that the block would have been meant to pass its heat to to the ICM, but i think its the other way around since the ICM is so tiny its obviously not meant to absorbe heat, the ICM should be the "hot" item and the block the heat soaker. This would mean the ICM gets really hot and the block absorbes some of this heat away.

Heres my problem, why would spacing it with washers help to reduce the heat at all then? Obviously the ICM is meant to get hot and vent off its heat to the block along with some heat to the air through the small heatsink on it. Adding washers would HURT its ability to cool off since air is a far far worse conductor of heat!
Seems like adding washers could be bad if the ICM gets hot, it won't be cooling off fast enough and possibly getting far hotter then before.

Could someone fill me in on if this is a correct assumption?

 

This mod has worked for many people. I think you have it mixed up on what is supposed to cool what. The heat sink is there to help cool the ICM. Since the heat sink is touching the block, which is also hot, it is harder for it to do its job. The heat sink can cool the ICM better if it has some air between itself and the block. That's the way i understand it .

 

I believe the thermal paste is between the ICM and the heatsink not the heatsink and the head.

 

Bingo.

 

Spacing it away from the head lets it cool easier because now the back of the ICM is able to have cooler air circulate around it as opposed to just the front and sides.

 

At the end of my instructions for doing the mod, some real world results are given.

I believe the thermal compound is also to be used between the bracket and the head in the normal configuration.

 

Ok I think I get it. The thermal paste is between the sink and the ICM, and not between the head and the ICM. How hot does the ICM run? Hotter than the block? I would guess its not supposed to run hotter then the block otherwise metal to metal contact would be more efficient for cooling...
Wonder if I could throw on a 2nd heatsink somehow to help even more

 

When I changed my coil, there was compound between both the ICM and bracket, and bracket to head..
I was thinking of putting a piece of aluminum plate [street sign aluminum plate? ] at back of ICM to assist cooling, and spacing it all from the head...
Haven't done it yet tho... [it's on that never ending list... ]
Charlie

 

That has been discussed, too.