Hey all, long time no see.

Ok, I've had this 97 Z-28 for about a year now, and it has a problem starting if it sits more than about an hour. Mods in sig.
It cranks and cranks, and usually takes 2-3 tries before it stumbles to life. It runs fine and hard, no leaning out that I can tell.

I hooked up a pressure valve to the fuel rail and with the engine off it reads 42 psi, and when running idles at 38-39 psi. Pressure goes up when engine is revved just fine.

When I shut it off it immediately drops to abou 25 psi and fades from there. When it starts at 42 psi it fades to 25 within 30 minutes. I believe this is too fast.

So the question is, is it a fuel pump, fuel pressure regulator, or an injector leaking down? How do I tell? I don't want to throw parts at it anymore. The intank fuel pump is stock, supplemented by the MSD inline.

It has a new opti, water pump, plugs, wires, coil, ICM, fuel filter and O2's.

Thanks for any help or educated guesses.

-Chris

 

Ok, after two hours, I have ZERO fuel pressure in the rail. What causes this, or what are common cold start causes?

Thanks for ANY help guys

 

pull the FPR vacuum tube off and check it for 'wet' gas. If the diaphram goes bad in it, it will bleed off into the vacuum side. Which means more gas at start up, and hard starting.

 

Testing

 

Awesome, thanks guys. I'll go check it right now! Results in a bit...

 

Any idea where I could get some of those "fuel line shut off adapters" or how much they are?

Or have most of you had good luck with vise grips? I'm sure replacement fuel lines are expensive as hell if broken.