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Bad Ignition Control Mod.? 92' Z34


Lex427
06-17-2014, 11:12 PM
I have had my 92' Lumina z34 for 2 years now. I love this car. I have replaced the fuel pump and fuel pump relay within the past year and a half. It is a great running car when it is running....except now. While I had it running in park. It just suddenly quit on me. No engine light. No problems before this that I have noticed out of the ordinary. Recently though, it has started to over heat a bit while idling, but not to the point that I have to shut it off. Anyway, while running in park it died and I could not get it started again. I had it towed home and found a blown 10 amp fuse that leads to the ICM. Obviously I am assuming it is the ICM. I replaced the fuse and held the gas to the floor and it started up. It now runs really rough. RPM's jump, a bit of sputter from the exhaust and the exhaust smells rich/dirty and there is a bit of misfire. I drove it around the block and there is a drag when it shifts. (not normal for this car). I was told it could be a busted cylinder also?? Any advice would be of great help!

Tech II
06-18-2014, 07:58 AM
Sounds like you have a bad misfire......last tuneup(plugs, wires, fuel and air filter, PCV)?

I'm thinking one of the coils is shorting out, blowing that fuse.....

Should not be driving the car like this, or you will be replacing the cat, also....

Check coil output with a spark tester....if you find a poor spark condition from one coil, swap it with another......if the problem moves to another cylinder, bad coil.....stays in the same cylinder, then bad ICM......

Any codes?

Lex427
06-18-2014, 01:09 PM
I haven't drove it anywhere to hook it up to any kind of diagnostic. It's pretty much been sitting in the driveway since this whole mishap. I will check the coil output here shortly to see what happens from there. Thank you.

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