Hi Ya'll, My girl is a 1999 Blazer LS 4.3L Vortex V6, and when I start her up then go directly back to the rear drivers wheel and bend down and listen there is a low whirring noise coming from somewhere behind the wheel or up underneath the rear end. Hard to tell without getting her up on racks.
I would like to have an idea of what it could be though before I take her somewhere because mechanics can take advantage of us girls, even though I know a little bit about some of these sort of things, this girl is knew to me.
Any help would be greatly appreciated.
PrecioustoHim

 

Electric fuel pump is inside the tank, probably what you're hearing. With the engine off, have an assistant turn the ignition to the run position, (don't start the engine). The fuel pump should turn on for ~ 2 seconds and then shut off. See if that's the same noise you're hearing.

 

Noisy fuel pumps are usually first sign of a pending failure. Of course no noise at all from the fuel pump is not good either!

 

Yep, I know what the fuel pump sounds like. This is a constant whirring almost buzzing sound like the sound of a hummingbirds wings and it is coming from right behind the rear drivers wheel when the car is running. After driving a ways, say 30 or 40 miles and getting out at a gas station I listen for it and it may be gone, then I may drive another 50 miles or so and it is back again. But is always there at first start up. It is not very loud, you have to lean over and listen for it by the wheel.

 

The only thing back by the left rear wheel is the fuel vapor canister and I do not remember there being a solenoid valve or any moving part there....but perhaps there is.

If when you hear this sound again, put a hand on the vapor canister to see if you can feel a vibration. I am going to check my '02 and see if it does anything like this.

 

Where is the vapor cannister located....sorry this girl and all of her parts are all new to me. I am used to my old 1960 Chevy PU. My goodness, wasn't he an easy fix!

 

Vapor canister is just rearward of the left rear tire. Black plastic box, about 3" X 6" X10" and looks like this: BWD Fuel Vapor Canister CP535: Buy best Vapor Canister at Advance Auto Parts

No moving parts, the only other thing back there is the vent valve, and all it does is click when it's activated.

 

Guy at the Chevy dealer says it is the fuel pump and it is normal.

 

That 1960 pickup looks great...except it has no bed....how did you haul anything?

Good to hear it is just the fuel pump.

 

Must be the way the picture looks. It had a long 8' bed on it. It was a really great truck. Bought him for $3000 in Mio Michigan at a flea market in the late 80's.