2002 Chevy Tahoe starting problems

[Hunter mohr]

I have a 2002 Chevy Tahoe 5.3 flex fuel and I’ve replaced fuel pump fuel filter evap solenoid Eva purge sensors new regulator new spark plug and wires had a shop scan said fuel injectors are pulsating right and I’m still having this same problem if it sits over night it will start run just fine but it you shut it off wait around 30 mines try to start it it will act like it’s going to die then rev up and run fine or it will start die then crank for 5-10 seconds then start and run fine idk what else to check

 

[Fless]

Carry a fuel pressure gauge with you and monitor the fuel rail pressure when the problem exists. Could be heat soak or vapor lock. Sounds like it's repeatable so easy to check.

Also, a crankshaft correlation procedure might be something to do. Need an advanced scanner or shop to do it.

 

[Hunter mohr]

Carry a fuel pressure gauge with you and monitor the fuel rail pressure when the problem exists. Could be heat soak or vapor lock. Sounds like it's repeatable so easy to check.

Also, a crankshaft correlation procedure might be something to do. Need an advanced scanner or shop to do it.

How do I fix heat soak/vapor lock?

 

[exp500]

Cycle key on/off a couple times before trying to start it.

 

[Hunter mohr]

Cycle key on/off a couple times before trying to start it.

Alright I’ll give it a try

 

[OR VietVet]

I guess anything is possible but hard to fathom a vapor lock problem. Yes, get a gauge on the fuel pump and get live readings. What brand is the fuel pump? Why did this parts replacement start anyway? Still has exact same starting problems that was there before the parts replacement?

 

[Fless]

When you expect this problem to happen (after your 30 min or so of rest after running it) check the fuel pressure without cranking/starting. Might be best to have the fuel gauge connected beforehand so it's in place for your tests. If you can connect it with a hose that will let you see it from the driver's seat, taped to the windshield, all the better.

Key on, engine off (KOEO) fuel pressure for flex fuel should be 48-54 psi. Then watch the gauge while you start it. Normal running pressure is 42 or 43 psi, right around there. But it doesn't sound like it has trouble running after you get it started.

 

[OR VietVet]

Yea, like @Fless, is saying, may have bleed down on the fuel system after shut off or who the hell knows.

 

[Fless]

I guess anything is possible but hard to fathom a vapor lock problem.

True. Vapor lock would be pretty rare; I'd focus on other causes.

 

[Hunter mohr]

So I did I pressure fuel test and it dropped to 0 psi within 2 hours I’m going to say probably a cheap pump I bought on Amazon for 60 bucks anyone thing different?