Hello everyone, I have a 87 with the 5.7 tpi motor in my iroc. The issue im having is the car will crank and not start when the car is hot. I have already replaced the ignition control module, the entire distruibutor, the ecu/ecm, the prom, the ignition coil, and recently a full tune up including o2 sensor. I have narrowed the issue down to a spark problem, there are no codes. when the condition takes place no spark goes from the coil to the cap. The coil itself is getting juice the whole time. I have 42 psi at the fuel rail.

The car will run again only when its ready for some reason. Does anyone have any experience with painless wire kits ? the only thing i can think of is some wire or connection may seperate when the car gets hot and no longer allows spark to take place.

 

no one has any ideas, scary.

 

Have you replaced the spark plug wires?

 

yes, im thinking its in the harness someplace. worst case scenerio is where it crosses the firewall.

 

Problem solved ! car sent to junkyard

 

Dang,
You could have at least parted it out and got some $ out of it.
If you dont have patients working on cars is not a good hobby for you.

 

cooter, its not a hobby when you it makes you want to drive your fist through the windshield. I have been using cars as a hobby for years. i have never stumbled upon a bigger hunk of crap in my life, whats worse is the only response i got was from you and five7kid. so i thank the both of you. im going to spend the $50 on a new pair of shoes.

 

Weve got a 3 alarm fire here folks. Take it easy

 

question is, why were you letting the car get hot?

 

i wasnt going to reply to this anymore. But i feel the need to say hot meaning reached operating temp. or perhaps over 160 degrees to be more exact. Anyway im looking in the paper for a new car this week.

 

in a surprising turn of events, someone i know purchased the car back from the junkyard and had it towed to a neutral site. i guess i will cool off a bit and start working again. it appears this car isnt done with me yet.

 

If it won't start at all when it is hot, check the two-wire harness that goes from the Distributor, to the coil. Computer does not start controlling timing until after 500 RPM. They are relatively cheap, and easy to find, so, simply replacing it, and seeing what happens would not be a real stretch.

When you replaced the entire distributor, which ICM did you put in there? Or, did you leave the one that was in it.... uh, in it? May want to check and see how much thermal paste is under it....

 

i had a car do that when i had a bad ground wire to the coil, via the block not being properly ground after doing my heads. it fried my coil and dizzy at the same time later on.see if u have juice to the coil it means jack if its not getting the circuit complete thru a good ground. my issue was on my mustang but no ground to the coil on a gm will stop spark too. my beretta used to heat up to norm op temp and do the same crap, coil packs were shorting out due to heat. u didnt mention if u replaced the coil.this is the car that doesnt have the coil in the cap right?

 

i tried several icm, including known good.

i noticed the two wire connector was in bad shape so i just picked one up, this is the car w/ the seperate coil.
it was replaced by me this week, again tested first w/ known good. i actually remotely mounted an accel coil to the firewall to keep it away from heat.

btw - thanks paul for letting me rip your running camaro apart as a test pig.

 

this problem was solved by rewiring the tach and ecm to the dizzy and coil.

 

Those types of problems are difficult to cyber-diagnose. Glad you found the problem.

Is it yours again?

 

yes, it was a momentary lapse of judgement. the judge has had mercy on my soul
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I was tipped by a different post calling out the white wire that is tach attached being a trouble maker with the open ground killing spark to the coil. That started making sense once i put the circuit together on paper. I played it safe and rewired the whole circuit.