Hey, I was driving a few days ago and my engine just shut off. No sputter. No misfire. Just cutoff as if I turned it off at the column and it would not start up again. Engine cranks but does not fire. I spent about half an hour trying to start it again and eventually it did, but it cut off again after about a minute of running.
Yesterday morning it started right up, ran for about two minutes and then shut off again and would not start. Verified that the fuel pressure is where it should be.
Today I hooked up a timing light to check for spark while cranking and there was none. After checking EVERY connection having to do with ignition I tried again and the timing light lit up and the engine fired. Damn thing shut off again after about five seconds. Spark gone again. I can't determine if I have a bad connection or if this could be some component that went bad.
By the way, 87 IROC, 5.7L TPI. Thanks for any suggestions

 

I know, only two hours old, just impatient.

 

Bad Ignition Control Module under the Dist. Cap or a bad pickup coil under the cap. Both are the most likely causes.

 

been there , done that . good luck .

 

iv had 3 pick up coils do that with my 3rdgens. yet it very well could be the icm, alot of people have bad luck with those. the pick up coil is harder to change, but its a cheaper part. the icm is easier to change, but more expensive part.

 

Thanks for the responses. I did consider the pickup coil and the ICM but I replaced the distributor with the Summit version. It only has about 6000 miles on it. Does anyone know how to test those items? I'll do a search also. Thanks.

 

http://www.justanswer.com/chevy/3yol...l-not-run.html

 

I had the pickup coil fail on me and a week later the module. I will allway replace them together cheap insurance. are you getting injector pulse ???

 

It also could be the actual external ignition coil failing. My factory one went bad and so did an Accel one I had. They also can cause the same problems as the ICM and pickup coil. Just an FYI that Summit dist. is made by Proform and I have seen a lot of there ignition parts fail very early.

 

Well I just finished checking the ignition coil, pickup coil, distributor cap, rotor, voltage at batt terminal for ignition coil, and ECM connections(just because I have resolved a loose connection at the ECM in the past). ALL check out. I did not check injector pulse but I confirmed that there is no spark at the plugs. Sooooo, I guess it HAS to be the ICM. Since I can't really test that and I THINK I checked everything else, I'll pick one up and let you all know if Proform failed again. Thanks.

 

Tunedperformanc, thanks for the link, there were some good diagrams that will be helpful.

 

OK gentleman, and ladies, it was the ICM. I farmed the original from my old distributor and it fired right up. Just because I love to waste my time, I put the Summit ICM back in to double check that something wasn't just loose, but no, it was garbage. Put the original back in and I'm back on the road. Thanks for the assistance, fellas.

 

Make sure you put Die-electric (spelling?) greese on the bottom of the ICM when you install it, helps keep it cooler and less prone to fail.

 

Does anyone else want to explain why bench testing ignition parts is a waste of time?

 

Damn Proform junk!! Just an fyi if yours goes out again put in a/c delco or MSD icm. They are a lot more reliable.

 

Yeah Stealth, I put some grease under the ICM before installing it. And Burnout, thanks for the heads up about Proform making Summit's ignition equipment, I will definitely avoid them in the future. I don't know how long the original will last being that it is about 24 years old now, so I think I will pick up an MSD and keep the original in my road kit for a back up.

 

Personally, I don't think bench testing anything is a waste of time. If you have the ability to test something out before installing it, why wouldn't you? Especially if that something may cause you to have to call in a tow one day. I'm not a gambling man.

 

I agree, but the results can sometimes be off without heat soak !!

 

Bingo, it has to do with the duration of the test and the ambient temperature. A bench test is not going to replicate the situation therefore electrical parts can stil test "good" when in fact, they aren't.

 

BINGO, damn I thought we were playing connect 4

 

CHECK. YOUR. GROUNDS.

 

Always sound advice. That was one of my early checks before getting more involved.

 

I wouldn't listen if anyone did.

Oops I guess that was rhetorical.

 

Just trying to help. I'll refrain from doing that for you in the future if you're just going to be a dick about it.

 

And I thought i was just being a funny dick, my apologies.

If I should need help in the future I sincerely hope you won't be a "dick" about it. I would still ask for help, the worst that can be said is no.

I'm all for bench testing because with all things being equal it proves the ICM is faulty and I wouldn't have put it back in just because it worked on the bench. That is why I bench test.

I'm a fluid flow experimental technician. I do not rely on bench testing and computer simulation alone, to see what's going on we use clear plastic to build a bench scale apparatus and clear pipe to make connections, unfortunately we can't apply heat which, in a refinery there's not much you can do without heat. The ultimate test is in the field where heat will be applied.

Raul.