Ran then didn't..

[no2guncntrl]

Thanks, guys. Yea I'm going to concentrate on the 2/4 test fire and the ICM.
Haven't found a place that tests the ICM but continue to search. I've pulled
the ground a number of times when changing out elec items. An IAC relearn
and whatever else it req's will get done once I get it to lite of. Any chance the
crankshaft sensor is causing this ? I'll try and get a screen shot of my old
scan tool when cranking the engine and post it up.

Thanks again.

[manicmechanix]

Originally Posted by no2guncntrl

Thanks, guys. Yea I'm going to concentrate on the 2/4 test fire and the ICM.
Haven't found a place that tests the ICM but continue to search. I've pulled
the ground a number of times when changing out elec items. An IAC relearn
and whatever else it req's will get done once I get it to lite of. Any chance the
crankshaft sensor is causing this ? I'll try and get a screen shot of my old
scan tool when cranking the engine and post it up.

Thanks again.

As I explained earlier if you are getting a cranking RPM reading from the scanner then your crank sensor is working and being powered through the ICM, and so your ICM is getting power also. This is why I said if you don't have spark on two or more coils then the ICM is indicating bad regardless.

Have you checked for spark on 2 and 4 or 4 and 6 yet? Most of the auto parts stores around me test ICMs, you probably have different stores where you are. The ICM doesn't even need to be tested off the car really. If you have crank signal which you're saying you have and if you don't have spark form any coils, then the ICM has tested bad by the process of elimination.

[no2guncntrl]

Thank you for your definition of two or more. I haven't had an
opportunity to test the coils. I plan to this weekend. I'm in hopes
of getting this thing going as I have Ca Smog coming up sooner
than later.

Thanks again,
bg

[no2guncntrl]

I took the orig ICM up to have tested. Found a place that does it and
it showed good. CRAP. So now I'll test the coils with them hooked onto
the ICM that's on there now. But so far it has not panned out to be an
ICM. [It was doing the same thing with the orig ICM. That's why after
reading a few things, I picked up another. Doesn't make much sense,
but I do dumb stuff like that]

I still think I should look at the plugs and pins of the ECM. I washed the
engine a few times a year ago, and maybe that's what is causing the
probs.

[manicmechanix]

Well did you ever test for spark at 2 or more coils? If you were getting no spark but were getting a crank signal, it has to be the ICM. Something is not adding up.

[no2guncntrl]

No I haven't had a chance to test the coils as suggested. I had the old
ICM with me during a work run and managed to find a place that
tested it. It showed green. One thing I was amazed at was how fast
it warmed up. It didn't take but a couple of minutes for the test and
the back was quite warm. Did GM ever put any kind of dielectric
grease or some kind of insulation between that back section of the ICM
to the alum mount ? Didn't seem like it. No wonder those things don't
last.

[manicmechanix]

Originally Posted by no2guncntrl

No I haven't had a chance to test the coils as suggested. I had the old
ICM with me during a work run and managcheck to find a place that
tested it. It showed green. One thing I was amazed at was how fast
it warmed up. It didn't take but a couple of minutes for the test and
the back was quite warm. Did GM ever put any kind of dielectric
grease or some kind of insulation between that back section of the ICM
to the alum mount ? Didn't seem like it. No wonder those things don't
last.

Well it seems like you originally had one problem then when you changed the ICM you got a no start, right? Your original ICM might not have been bad (depending on how reliable the autoparts store test was), but the replacement one could be. If you have a no start problem, you need to check for spark. It's simple to do. All of the 3 front plugs are pretty easy access and each runs to a different coil.

[no2guncntrl]

I agree and am going to do the testing this sat morn. I need to get to the
bottom of this if for no other reason than it's very irritating to have a 1991
car with only 50,000 miles on it just rotting away.