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I have a 1993 Chevy Corsica with a 3.1L V6. It has the DIS Waste Spark ignition system. It starts and runs but only has spark from the 3-6 coil. I'm missing spark between the 1-4 and 2-5 coil towers . I replaced the 2-5 coil because it failed the primary resistance test but still doesn't spark. My question is: Can the crankshaft position sensor(s) trick the ICM into triggering just the 3-6 coil and keep the timimng corect to allow the engine to run...I know the engine doesn't run very well this way but it runs good enough to do some troubleshooting. Compression and leak-down tests passed. I'm pretty sure the ICM is toast but I thought I would ask you anyway.
Thanks!
Matt
I'm 56 and as a shadetree mechanic, since 1970, I work on everything I own and pretty much everyone else's broken stuff in the neiborhood.
So you started your career age seven, that's cool....
The crank sensor ain't likely to cause this kind of problem. If you had a scope you could check its signal, or you could induce an appropriate signal intpo the icm and che k the coils activation outputs ..
If none of the above applies you can take the module to autozone or a similar place where they will check your module free of charge.
Suerte!
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
The following user(s) said Thank You: ScannerDanner, Noah, mtwoods1
Most likely you have faulty drivers in the ICM (common on these) and since you already replaced one of the coils and it still has no spark, you've pretty much confirmed it already.
On some models, it is possible that a crank sensor can wig out and cause one coil not to fire but I've only seen that on the 3300 and 3800 models. This 93 3.1 only has a 7x crank sensor that cannot fail the same way a hall effect can in the dual crank sensor set ups I mentioned on those other engines.
Here is a way you can test the ICM drivers.
Remove the coil and put a test light between the two primary pins, it should flash when you crank it.
Swapping coils was also a good test. (They are all the same)
Yeah, my dad ran a Shell station in Niles Canyon just outside of Union City California. On the weekends I word dress up in my little Shell uniform, pump gas and mess around in the bays...unheard of in today’s society. I had a great time there! After 3 years he had to close the doors though, he never charged enough in the garage and other gas only stations went up all around. After that, we went out dirt bike riding almost every weekend. That’s where I started fixing motorcycles.
I didn’t know autozone could check ignition modules...well not this type anyway.
My kids bought me an O’scop Kit for Christmas but I haven’t been able to get it to run a trace properly yet.
Maybe I’ll make a simple signal generator. That way I will be able to test all my ignition modules at home. I watched SD’s video about what the ICM triggering waveform should look like so I just have to mimic that.
Thanks again,
Matt Woods
The following user(s) said Thank You: ScannerDanner
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