2000 Bravada - High pitched whine

[chadshu]

Hi,

I have a 2000 Bravada with 122K miles. I just purchased this vehicle and recently it has developed a high pitched whine, almost like a combination of whistling and a soft buzzing. The sound occurs right when the engine is started and it sounds like it is coming from the middle underside of the car and not the engine. The sound is constant and engine speed nor vehicle speed effect it. The sound is obvious when you are standing outside but isn't loud enough to be noticed when your inside the vehicle. It doesn't seem to have any effect on driveability, at least none that I've noticed, and there are no warning lights (but I don't know about trouble codes). Any help or advice would be greatly appreciated.

[Chris Stewart]

Listen for it as soon as you turn the keyswitch on without starting the motor, I'm thinking you're hearing the fuel pump...they're noisey that way. Learn the sound and when the sound changes, you'll know the fuel pump or battery is going bad.

[chadshu]

Originally Posted by Chris Stewart

Listen for it as soon as you turn the keyswitch on without starting the motor, I'm thinking you're hearing the fuel pump...they're noisey that way. Learn the sound and when the sound changes, you'll know the fuel pump or battery is going bad.

The noise isn't there when you first turn the ignition without starting the engine, but it is there for a few seconds right after you turn off the engine. I did notice the exact same sound coming from a Chevy Blazer and GMC Sonoma the other day so I guess it's "normal". Thanks for the response Chris.

[Chris Stewart]

Way to go Chadshu!
As you've observed, many GM suv's share the same systems as our Bravada's including the fuel system.
My '97 fuel pump keeps running a few seconds after stopping the engine too.
My '92 fuel pump starts as soon as you turn the keyswitch on...different years and systems.