I've got a long crank on start up only. I can't find any gas leaks. This is a return fuel system (from the tank to the fuel rail and back to the tank). Is there some sort of "check valve" or component that acts as such in this system? I saw a few other posts mentioning a fuel pressure relief valve; would this the problem child? Where is it located? I bought a Chilton's manual, but it really doesn't seem to be worth the paper it's written on. It looks like the fuel rail is burried under the intake manifold; is this pressure relief valve under there? I don't have any issues at idle, part throttle, nor WOT...just at initial start-up, so I don't think I have an issue with the fuel pump unless that is where the "check valve" is located. Please help me...I'm sort of confused as to where to attack this problem.

I've run into this problem many times in the 5.3's, 4.6's and alot of GM FWD's.

Probably your fuel pressure regulator. (Located on driver's side of engine directly above the valve cover gasket on the fuel rail) It's about 1-1/2" in diameter held on by a metal retainer clip.

Testing: with vehicle off, pull of the small vacuum hose. If any gasoline comes out of the regulator or hose, your pressure regulator is BAD. Try it both with cold and warm engine if you don't see gas right away.

The regulators are available at any parts house for about $50. Made aftermarket by Standard ignition, and several others.

Good Luck!

Jim

The previous post was made in reference to the 5.3 and the 4.6 Engines. But call me "Dumber than average". Your Sub probably is still the "Classic Silverado" body style with the 5.7. Sorry for jumping the gun if you have the 5.7. Jim

I've got a 454 under the hood of this beast; I think that translates to a 7.3L? Anyway, it looks like the fuel rail is under the intake manifold; does this mean the pressure regulator valve is under there too?