babadioum

I'm not getting any spark from the coil-to-distributor cable, that should most probably point to a faulty coil, correct? IF my ICM was faulty, I'd get spark at the coil-to-distributor cable end, wouldn't I? Thanks in advance

ironwill

If the ICM is at fault, there will be no spark at all. If you don't have a factory shop manual, you can find ICM troubleshooting steps here: https://easyautodiagnostics.com/gm/4...ed-icm-tests-6

babadioum

Thanks, I'll check it out So then, 1) coil, OR, 2) ICM can be faulty, correct? I mean, assuming ICM is OK, but coil is faulty, I'd still wouldn't get spark, correct?

Tuned Performance

iTrader: (92)

If the coil is bad it can’t produce spark. Go through the trouble shooting link.
start with check power to the icm key on at the pink wire at the icm connector.

ironwill

The coil gets it's signal from the ICM; both must be functional in order to produce ignition spark.

These are old cars, with old wiring and old connectors. Check everything, as directed in the link I provided before you throw parts---and $$$---at the car.

babadioum

will do the test

babadioum

Here is my dilemma: IF no voltage, pick-up coil is faulty; that's guaranteed, but IF there is voltage, ICM can still be OK while ignition coil is busted, so if there is voltage, the test is ONLY conclusive as long as I guarantee a working ignition coil, correct? So I must check the ignition coil FIRST and ensure it works, correct?

Tuned Performance

iTrader: (92)

The pink wire goes from the ignition switch to the coil then onto the icm. It powers the coil and icm key one engine off.
if that’s fine remove the cap and check for voltage while cranking at the pu coil.
if that’s producing the correct voltage it’s the icm.

babadioum

Here is the scoop: the tests clearly exonerated the coil and p-u coil which left ICM as the sole culpable item, so I put the spare to no avail AND the test still pointed to ICM; since two busted ICMs in a row is almost very unlikely and since I was in the midst of a full harness replacement, adapting a swap kit from Payless 60103 which practically becomes an OEM replacement with few ECM and 15-way connector hook-ups based on the OEM mapping (I'll post the work later), I decided to first fix the SES light & ALDL circuitry, crank the engine and get the probable code(s) set so I can accurately pinpoint to the actual problem(s). After wrestling with few hiccups, I got the diagnostics circuitry working and received only the code 46 (VATS): Since the ECM line to VATS sensor was OK, that led me to a unhooked ground off the C7 bulkhead connector which I promptly fixed. Then cranked to no avail, so I circled back to the original ICM, the one I knew it was working before the whole overhaul started since I already identified the replacement also possibly faulty, and voila! Runs like never before
PS: Since VATS was the issue, the fuel was cut off which was probably having an effect on ICM circuitry, at least that's what I assumed for both being indicated as "faulty", but it turned out only one ICM was in fact faulty

Thank you all for your quick and helpful assistances.