It sounds like you have intermittant problems. Coils can have more issues in the secondary due to heat because the wires are so tiny but that won't blow a fuse. The primaries don't seem to fail too often because that is thicker wire, but they can fail, and they can be intermittant with heat causing the bad connection to expand and contract. The ICM can fail due to heat because it has semiconductors and solder joints which can fail. So, if you can't eliminate the faulty part by substitution, you need to stress the parts somehow. You can use a heat gun and cold spray to aid in troubleshooting - this will work better on the ICM because it is harder to heat or cool a coil - you could do it but it takes much longer. 6500 Ohms sounds like you are testing the coil secondary windings, not the primary. Maybe you could measure the primary before and after it pops and see if that changes. If you pop the fuse and immediately after pulling out and can put in a new fuse and have it run again, then I'm not sure just what that could be except some kind of short circuit in wiring somewhere.

Ill check the manual for you and see if there is something we are missing that would be helpful.

Hmmm, it looks like an ICM shorted will throw a code DTC 42, open circuit would be DTC 41... Actually DTC 42 seems to be ICM losing it's voltage and it would only be set during cranking. So if you tried to restart after losing the fuse, that should set the code.

It looks like the 10A fuse goes to the pink wire going to the coil primary, then the wht/blk wire from the other side of the coil primary to the ICM or possibly the pink/blk wire going from the primary to ICM could be the only wires that could possibly blow that fuse, if it wasn't the coil pimary or the ICM themselves doing it.

 

You said it works at idle, so you aren't likely going to find any problem with a meter. There is no way to do any meter testing when the trouble is only occurring when running above idle.

 

Just for my own sanity I took a blown fuse and broke it up. Stuck the piece of the fuse on the non 12v side of the ignition fuse holder under the hood, and put it on the multimeter, and the other end to the battery ground.

I wiggled all the wiring on the coil, icm, and crank sensor, and the wiring on the black 10 pin connector near the icm (specifically the pink wire inbetween the brown and blue wire).

No beeps, so there is no short in the wiring - that I am now totally convinced of.

I also pulled the fuse box itself and checked all the wiring underneath and it appeared to be as good as new.

I guess I'll be heading to the junkyard on Monday and pull an ICM and a coil from a couple of vehicles.

I cross referenced the part number and it appears that it was on a lot of chevy vans and trucks so I shouldn't have a problem finding those parts.

I will post my results when I'm finished.

 

So I went to the yard today and pulled 2 icm's. One from an Astro and another from a Sierra 1500 or something, both 97's. I also took a coil from the truck, as it appeared to be the same.

Well I put the ICM on from the ck1500 and the car fired over and drives fine.

I have put like 5 miles on it so far and it appears to be running smooth so far and hasn't blown the fuse.

I'll keep my fingers crossed until I put a few more miles on it but so far so good.

I will also mention that the car was acting funny a few days prior to this but I assumed it was the starter. I would push in the clutch and turn the key, and while it was turned, the starter wouldn't turn it would make a faint "click" and then after a few turns, or just holding it in the start, it would finally engage. I figured it was the solenoid getting weak. It did this fairly consistently while I was having this problem. Since I replaced the ICM it has not done that, but I haven't seen any wiring that shows that those two things are related and I'm thinking it was just coincidence.

I also find it a very strange coincidence that my ICM would go bad the day I finish a plug wire job. Very strange.

Thanks for all the help CZ28.

 

If you haven't already done so, space that ICM away from the head with a few washers to let it get a little cooler air.

 

That hadn't crossed my mind, I'm going to do that tomorrow.

In all fairness though, that ICM did last over 140k. My coil is still factory with over 140k, and my stock opti lasted to 130k.

I've been pretty fortunate as the only things to fail on my car in the past 13 years have been the Opti, ICM, and Fuel pump.