We have put around 75k miles on our 88 duke (now at around 115k on odometer) over the last 6 years. Last night the car wouldn't start. No fuel or spark and the tach doesn't budge. I am fairly certain it is the ICM, but I cant confirm yet as I haven't repaired it.

This will be the third ICM I have had to replace since we have owned it over the last 6 years? It has the metal heat shield on it. I am installing as outlined in Ogres cave. I have replaced the wires, plugs, coils, CPS with quality OEM parts. What could be causing this?? As I am typing this I am speculating that a voltage drop on some ground be the cause of short life?

Any thoughts?
Thanks!

The heat shield was my first thought, but you already have that. (Good job!)
Have you pulled the cover for the wire loom to check for any shorts?
Over torquing the bolts that hold it to the block can damage it as well.
Check all of your grounds.
Any fluids that might have splashed onto it?

The crank sensor on my 88 duke was broke in half when I removed it for my rebuild, so you could check that as well.

This is all I can think of, sorry.
Good luck!

I LIED!!!!

I took it out today and no shield plate!!!

That is obviously my problem...haha

Well at least you figured it out.
Now the fun part will be finding a used one.

I had to make mine.

quote Originally posted by Zeak: Went to the parts store and paid $2.99 for a small exhaust connector. It's 18 gauge galvanized steel. Made a paper tracing of the pim and them cleaned it up and traced it onto the connector. Going to cut it down the back side and unroll it and then cut the holes.

Thanks for the picture and description of your home made shield.

I made one from a piece of zinc finished scrap sheet metal I had lying around. It was about 16 gauge, so thicker than the OEM shield. I packed dielectric grease into the coil terminals to make up for the added thickness. It seems to fit well. I installed it and the car started up and ran properly. I'm calling it good and hoping we wont need another ICM in 2 years!!!

I'm not sure what PIM shield does but missing that can cause problems. Not all PIM (V6 V8) w/ same coils uses them.

Check ground where bolted to trans bell. Grounds bolted to engine etc likes to rust.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

Had the same problem with my 88 duke a few years back. PO didn't put shields back when replacement coils were put on. Car would not start after a long drive during summer months. After checking just about everything I could think of,I took off coils, both shields were missing. Went to local GM dealer next day and they were able to locate some at a dealership in Nebraska. Put them on and I never have had that problem since.

Running in So Cal heat I found the 85 GT ignition module did fail sometimes and always suspected heat. The heat sink paste is important. Transistors fail between ?185-250F, depending upon the "grade" of transistor. For that reason only buy top line modules (is there such a thing nowadays?). Overheating engines will destroy the module, I think. The fan and air tube are a sign of GM's concern about heat damage. Now in the NW I have removed the fan and tube with no problems. I believe Radio Shack sells a little tube of heat sink paste.

[This message has been edited by hobbywrench (edited 01-18-2015).]