No start issue

[Tan1998K2500]

Hey, I read a lot on this thread and I figured it would be the best place to ask about my truck. I have a 1996 GMC k1500 with a 5.7L vortec engine. It recently developed a no start issue where when I drive around and get somewhere, then turn the engine off, it won't start up for 10 minutes to 2 hours. But it will always start up when it has been sitting over night. And it runs great when it is running.

 

[Eveready]

Failing fuel pump maybe? When it is running does the pump make any extra noise? Seems like something is heating up when it runs and opens when it shuts off, then has to cool down to work again.

 

[Tan1998K2500]

Thanks for the reply. And no, there is no extra noise. And I'll try replacing it tomorrow morning and see.

 

[lessersivad]

Thanks for the reply. And no, there is no extra noise. And I'll try replacing it tomorrow morning and see.

DON'T fire the parts cannon till you verify if it's ignition or fuel related.

Simple shadetree method is to give the engine a snort of carb cleaner when it won't start.

IF it starts then dies after the carb cleaner is burned up then I would say fuel issue. IF it don't then it's ignition related.

Hope this helps.

 

[Eveready]

DON'T fire the parts cannon till you verify if it's ignition or fuel related.

Considering where the fuel pump is located this is especially true. Unless your truck has a port installed in the bed, this is a genuine pain in the ass. If there IS a port installed you might check connections at the pump for overheating or oxidation but the shadetree test should come first.

My guess would be electrical, possibly a ground or more likely an oxidized connection that is changing states when heated.

 

[lessersivad]

Considering where the fuel pump is located this is especially true. Unless your truck has a port installed in the bed, this is a genuine pain in the ass. If there IS a port installed you might check connections at the pump for overheating or oxidation but the shadetree test should come first.

My guess would be electrical, possibly a ground or more likely an oxidized connection that is changing states when heated.

Or possibly ignition module or coil.

1st do the 'snort test' then go from there would be (IMHO) THE way to go.

 

[Tan1998K2500]

Well, I know its fuel related because when it wouldn't start, I put a fuel pressure gauge on it and it had no pressure. And I replaced the coil not too long ago with a MSD coil. All of the spark plug wires are new as well. And I for sure have spark. So I know it is a fuel issue.

 

[east302]

What was your fuel pressure? Spec is 60-66 psi.

At first it sounded like a failing coolant temperature sensor. If you had a scanner, you could see what it was reading to see if it was some oddball number. Another check for it would be to hold the gas to the floor as you crank it. That puts it in clear flood mode, temporarily stopping injector flow.


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[Tan1998K2500]

According to ultragauge, it was a normal temperature. And same with the dashboard temperature gauge. And when priming, it was 40ish psi. With the engine running, 50ish.

 

[Tan1998K2500]

Well... now the world will never know why it won't start because i went to replace the fuel pump and one of the fuel lines were dry rotted so it split. And i don't have any way to replace that yet and I'm about to go to boot camp so it will be awhile. Thanks for all of your guys' suggestions though