Car will not stay running

[trophy421]

Hello, I am having a problem that hopefully somebody else has had before and can offer advice on. My car is a 2002 Z28 automatic, completely stock, with 97,000 mles. A few days ago I started my car in the morning to let it warm up before driving (was 19° outside). It was idling fine when I locked it up and went back in the house. Came back out a little while later and it had died. It would restart, but ran rough and would only run maybe 5-10 seconds before dying. I got a ride to work, then tried again when I got home. Was still below freezing, and it started and ran for maybe 1-2 seconds before dying. Immediately after that, when I tried to start it, it would crank but not fire. It is now well above freezing and still doing the same thing. Like before, it will start and run for1-2 seconds, but only after it has been sitting for a pretty long time. On subsequent attempts it will crank but not fire.

When this first happened, my first thought was frozen fuel line due to the cold, especially since it started at first - I was thinking it was using up the gas remaining in the engine and maybe the forward part of the line. But now it's like 60° and won't stay running, so that's not it.

It seems kinda weird to me that it'll run for 1-2 seconds after sitting for a while. I can hear the fuel pump priming. It's almost like the fuel pump is sending just enough gas to let it run 1-2 seconds, but then won't send any more.

I have a code reader and plan to check that, and plan to check for any blown fuses, but time is tight for me right now so I haven't done that yet.

Any help or ideas would be appreciated!

[cammed goat]

Have you checked your fuel pressure? Have you checked your coolant temp sensor(on the driver side head near the manifold)?

[trophy421]

No, have not checked the fuel pressure or coolant temp sensor. How does the coolant temp sensor fit into the picture? Why would that keep the car from running?

[Smittro]

Sounds like a dieing fuel pump to me.

My 01 did exactly the same thing when the pump died.

Let it sit and it would prime and start then die and would'nt start after that unless it sat for a while.

Then it was just a repeat of starting and dieing then no start.

I would do as Rich suggests and check your rail presure, should be ~ 58psi. for the ls1 +/- 2 to 10 psi. running.

[Smittro]

No, have not checked the fuel pressure or coolant temp sensor. How does the coolant temp sensor fit into the picture? Why would that keep the car from running?

A faulty coolant sensor can fool the PCM into seeing an over heat condition even if the engine is cold.

Durring an over heat while the engine is running the PCM pulls timing in reduced power mode to protect the engine.

If the PCM pulls timing prior to start up it may very well not start or may not stay running if it does..

However,, I would check rail presure first.

[trophy421]

Smittro, sounds like it may be the fuel pump dying since yours did exactly the same thing. I was thinking that since I could hear it prime the pump was OK, but maybe it's not dead, just has inadequate pressure?

[Smittro]

Smittro, sounds like it may be the fuel pump dying since yours did exactly the same thing. I was thinking that since I could hear it prime the pump was OK, but maybe it's not dead, just has inadequate pressure?

Mine would prime, but the pump was weak and could'nt maintain adequite presure while running.

I suspect that's what's going on here, but we won't know for sure until you pull a rail reading.

[trophy421]

OK, thanks for the info. I am at work now but will plan to get a reading as soon as I can.

[Smittro]

OK, thanks for the info. I am at work now but will plan to get a reading as soon as I can.

Ok, let us know what you find.

[trophy421]

Sorry I never got back. The fuel pump ended up being dead. It's replaced now.

[Smittro]

Glad you got it running again!