snimmo

I recently replaced a fuel pump on a 97 GMC 1/2 ton 350 pickup. All went well except for one thing. I am having a sound that I can't locate near the top or in the fuel tank. At first I thought the O ring was not sealing the pump mechanism when I placed it back in the tank. After dropping the tank low enough to place my hands all around the fittings and seal I did thorough testing to try to locate this sound. It does sound like air (like a tire leak) so I replaced the vacuumn line but no luck. I simply cannot find a leak anywhere. The is no fuel leaking so I know it is not the pressure side. Also I tried diconnecting the vacuumn line completely and started the truck. Still had the sound. Any ideas? Is it safe to drive it this way?

Thanks

Snapps

iTrader: (39)

GM fuel pumps are very noisey. I had one replaced after that the noise was still there so the dealer threw another one in once again noise was there. This was on my 94 GMC sonoma. To this day with a full tank I still get a whining noise.

Hope that helps

Jeff

Black LS1 T/A

Do you have access to a stethoscope?
You may can get closer to where the noise is coming from than what you've been able to so far.

If the noise changes in frequency when you place a load on the electical system (turn heater/fan on, adjust windows), because these may vary the current to the pump, it MAY indicate the noise is coming FROM the pump.

Just throwing some ideas out there...

Good luck!