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I got a 95' northstar engine that cranks but no start, no spark I was able to check crank and cam sensors signals at the ICM. I got around 1.5 VAC while cranking which I think is good. However I don't have a oscilloscope to test the ICM output signals (24X, 4X, 1/2X) can you guys suggest how to test accurately this signals without an oscilloscope???
it matter the polarity of the crank sensors even when this are AC???
Hi there, welcome to the forum!
It's going to be hard to get an accurate measurement of these signals without a scope. At least you're seeing something with your voltmeter. Unfortunately, that's probably about as good as you're going to get without a scope. Have you checked for injector control and coil control? You can do that with just a testlight or your meter.
This is a great video describing how the GM bypass ignition system works.
The testing in this video will also be very similar to your Cadillac.
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