Testing GM EFI Distributor Spark and misfire.

Thanks to ASE doc for this quick guide instead of reading the entire manual.

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You can test the pick up coil with an ohmmeter, should be 800-1000 ohms. You can
sort of test the crank referrence pulse(ppl/wht wire) using the voltmeter set on
the lowest scale, it will start as a low voltage DC signal and increase with
engine speed. The best way to test this signal though is with a scope where it
will be a digital(on/off) signal 0v to 5v, with frequency increasing with engine
speed. I have removed the dist and turned it in my hand with the key on to
produce and measure the signal. you have to run a test lead to ground the dist
body. A steady misfire whether it's ignition or injectors is fairly straight
forward. Test spark at every plug. If you have an engine analyser I would tell
you to do a power balance test. You can perform a simple balance test by pulling
or shorting one plug wire at a time. I generally use a test light to ground out
one wire at a time by piercing the boot at the cap. Look for cylinders that
don't drop rpm when you kill them. Once you know which cylinders are missing,
figure oput why by testing injector pulse, compression, etc.

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