After days of searching on here it's time ask you guys for help. I have a 96 Z28 with about 60,000 miles and no mods. Lately my problem has been that I can start the car when its cold and drive it without any issues but as soon as its warmed up and I shut it off and try yo restart it, it will start, run for a couple seconds and then die. Then, if i try to start it after that, it will crank and not start unless I wait 5 minutes or so and itll start just fine. I just replaced the ICM thinking it was getting headsoaked and did the fuel filter as well but neither have helped. Also, its not throwing any codes so im not sure where to go from here. Thanks in advance for the help.

 

One possibility is a faulty coolant temp sensor - the one in the water pump housing that feeds the PCM. If its indicating lower than actual temperature, the engine may be running too rich on the cold start enrichment.

 

That would be nice since they're pretty cheap. Is there any way to test those to make sure?

 

Alright, finally got around to hooking up a fuel pressure tester. I'm reading 30psi with the key on engine off and 35psi while its running. It hits about 40psi max if I rev it some.

 

At idle, pull the vacuum compensation line off the fuel pressure regulator. Should read 43.5psi, with anything between 41-47psi acceptable. Reattach the vacuum line, and pressure should drop 6 to 8 psi below the "no vacuum" reading ( stock cam). When engine is shut off, fuel pressure should not drop quickly. If its holding 30psi for a long time, its OK.

 

Thanks Injuneer, I put the tester on it again today while it was hot and was reading around 30psi while running. I then turned it off and put to key to the "run" position to prime the pump but was only getting maybe 1 to 2 psi max. After it cooled down some I tried to prime it again and it was around normal. Definitely an issue there. I then took the vaccum line off and it read a maximum of 40 psi while running, with the hose off. Has anyone heard of a fuel pump acting this way once the car has been warmed up? Could it be a relay or something or is my pump just shot?

 

also your fuel pump could be heating up and when it does it stop working until till in cools back down

 

Looks like the fuel pumps finally shot. Won't start and getting a big ZERO on the fuel pressure. Ordered the Racetronix kit earlier with the harness. Anybody have some experience with it?