cclay6482

I hope someone can help me out with this one...my 1999 Tahoe (5.7L) that I bought used has been having an intermittant problem ever since I bought it. Seems that after it sits for a while, which usually means overnight, it will not start at all, no matter how many times it's cranked over. If you leave the truck sit for 30-60 minutes, it will crank right up like nothing was ever wrong. I've changed out plugs, wires, cap, rotor, and cleaned the IAC valve. Fuel pressure at the shraeder valve looked good, 55-60 psi.

This morning, it did it again. However, I was in a position this time to try a couple of things out. First, I primed the truck at the TB, and sure enough, it would start and run temporarily on the prime. With the key on, I took the cap off of the schraeder valve on the fuel rail and depressed the stem and got nothing; no air or fuel coming out of the valve. Clearly this was not right, so I had my wife cycle the ignition key off and then back on while the stem was depressed. The fuel pump sprang to life and fuel started pouring out of the valve. I put the cap back on and the truck started fine. I don't think this is an ignition switch or electrical problem, as in trying to start the truck all the previous times I've cycled the switch on and off numerous times with no luck. It almost acted like it was air locked. This truck has 115,000 miles on it.

Anyone with previous experience on something like this?

Thanks!

73shark

Don't know how hard it would be but need to check voltage at fuel pump with key on. If that's OK, then probably fuel pump is bad.

Dondobe

I have a "99" and my fuel pump went out at 134K. I was a similar problem and then one day I turned it off at the store and that was it. It just wouldn't start.(of coarse I just filled the tank!) Because of environmental issues (neighbors), I had to have someone else fix it $$$.
Good Luck, Dondobe

Have you ever changed the fuel filter? It's on the frame under the driver's side.

viperjuice

Well sounds to me like it's time for a new fuel pump bud. The reason it's not starting after it sits over night it because the fuel pump is allowing the fuel pressure to bleed back into the tank "especially when sitting over night".. One way or the other, you need a pump.. Till then, try turning the key on for a few seconds and then off for a few seconds and then back on for a few before starting to prime the system. oh yeah do the filter too while ur at it, but the pump is deffenitly the problem there