5.7 vortec reving and it dies?

[stutaeng]

If they are pretty much the same pressure drop, then likely not injectors.

Your 50 psi fuel pressure seems too low. I'm surprised it actually starts. Spec is like 60-62 psi, although my Vortec engines seemed to run at 55psi w/o any problems.

You said 50 psi is constant even when you rev it up? Also stays at 50 right before it dies? Could be fuel pressure regulator, or perhaps fuel pump. Need to diagnose further.

But on video I think I see some surging at idle, no? That could be a vacuum leak. Do you have a vacuum guage to hook up?

Edit: The fact that it dies "after" you let off the gas does not seem to indicate fuel delivery problem.

 

[Schurkey]

If they are pretty much the same pressure drop, then likely not injectors.

Agreed.

Your 50 psi fuel pressure seems too low. I'm surprised it actually starts. Spec is like 60-62 psi, although my Vortec engines seemed to run at 55psi w/o any problems.

Is the gauge accurate? No-one seems to verify them, or compare to other gauges. Same with compression tester gauges.

I bought a replacement gauge for one of my fuel pressure testers; the original gauge wasn't providing correct pressure readings. (I converted that tester from 0--100 psi, to 0--30 psi for low-pressure TBI systems.)

You said 50 psi is constant even when you rev it up? Also stays at 50 right before it dies? Could be fuel pressure regulator, or perhaps fuel pump. Need to diagnose further.

Yes.

But on video I think I see some surging at idle, no? That could be a vacuum leak. Do you have a vacuum guage to hook up?

I wouldn't expect a vacuum leak to show up on a vacuum gauge in a meaningful way.

Edit: The fact that it dies "after" you let off the gas does not seem to indicate fuel delivery problem.

I'd wanna know what the IAC is doing.

 

[Osteoblast]

How can I check the IAC?

 

[stutaeng]

I don't recall how to test it, but I found this video. Different engine, but probably similar or the same for the 5.7 Vortec. This channel is awesome for doing diagnosis BTW.

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[Osteoblast]

I changed the crankshaft sensor and now it runs. No more problems so far.
Fingers crossed.
Passed emissions and everything else, got insurance and soon on the road.
We'll see what's the next issue will be.
Never ending journey.

Thank you guys for your help!