HELP!!!! 92 5.7 WON'T Start after Tune Up????

[bigbear]

Ok here is the deal!! Just did a tune up on my 92 RCLB with the 5.7 TBI . New cap, button, plugs, and wires. Started the truck and ran fine. Finish putting everything back together backed out of the shop for a test drive and the truck cut off. Checked all my connections, wires, and everything else. Went to the parts store thinking I had a bad ignition module and the guy at the parts house said it wasnt the problem. Returned home put the thing back together again and was going to test the spark with a screw driver in the coil wire. The damn thing started right up. So again put the wire back on it started and run for about 2 min and shut off again. Now the damn thing wont start at all. No Fire, Checked all the connection again . everything looked good. I am pulling my hair out now!!! Dont know what to do. Any suggestions would be most helpful. Thanks Bear

 

[SAATR]

When you have the no start/no spark condition, are you getting 12V to the coil and module? Use a test light or multimeter and check and see what's there. Your problem may be farther upstream, like the ignition switch. It really sounds like something is warming up and shutting down, so I see why ignition module would be top on your list. Coils don't usually fail intermittently like you're seeing. They usually will get a short in the windings or an intermittent short caused by moisture through a cracked housing, and will be weak and misfire before they just quit. Your pickup coil in the distributor could also be the culprit, if everything else is kosher. If you can borrow a known good distributor from a buddy, that would be the easiest test. Aside from that, there are procedures for checking the resistances of the pickup to determine if it's faulty.

 

[stroker87]

I had a MSD ignition box do that same thing, some times would run great then nothing at all

 

[bigbear]

YEAH!!! got it straight now. Bad ICM. Had it checked twice at Advanced and Autozone and checked out fine. Then I took it to Oriley the guy there knew what he was doing. He run the test 5 times and it fail 3 of the 5. Needless to say replaced it and now it runs like a champ!!!

 

[DRAGGIN95]

YEAH!!! got it straight now. Bad ICM. Had it checked twice at Advanced and Autozone and checked out fine. Then I took it to Oriley the guy there knew what he was doing. He run the test 5 times and it fail 3 of the 5. Needless to say replaced it and now it runs like a champ!!!

That's great to hear, I am glad you found the problem!