2007 Yukon drilling noise

[bmauter]

My 2007 Yukon 5.3L with AFM made a new noise yesterday. I have about 170k miles.

It originated from what seemed like the driver-side rear and sounded like a dentist’s drill. I got it once at low speed, once in a parking space and once at highway speed. On the highway i popped it into neutral and pressed the accelerator. The noise changed with engine speed. It can’t be something with the wheel.

I’m leaning towards a fuel pump going out.

Thoughts?

Thanks,
-Brian

 

[Doubeleive]

sometimes a noise can sound like it's coming from the back but is really coming from somewhere else, but there is also the air pump in the same location if you have air ride.

 

[bmauter]

Thanks, I've been trying to reproduce the sound with others in the car to better find the location. I don't have the air ride.

 

[swathdiver]

Not under the hood at idle? Fuel pumps are pretty quiet while submerged in fuel. Get a long extension and use it as a stethescope, stick one end to your ear and touch the other to your accessories, like power steering pump, alternator, etc.

 

[NGAneer]

I'd look at ABS actuator. My 99 had a similar noise coming from under the driver floor when I was in college. I forget what happened but it made the same type of noise, like a small electric motor running.

I also had a bit of a "whirring" noise coming from the PS pump that I just changed, but I think that would be pretty obvious in terms of location.

 

[bmauter]

I went ahead and replaced the fuel pump. I already had one.

[backstory on why I already had a new fuel pump]
A couple years ago I ran the truck out of gas. I thought I ruined the fuel pump as the engine sputtered and coughed even though the tank was full. It was air in the fuel line but I didn't know I needed to bleed that out from the fuel rail. A couple days later, I tried it again and it has been perfect ever since. I bought a fuel pump, fuel pressure gauge with bleed valve and a Lisle quick connect tool set just in case. Thanks RockAuto!
[/backstory on why I already had a new fuel pump]

Anyway, I replaced that fuel pump, bled the fuel line and it's been fine. Actually, it's been better than fine. I had been noticing some strange things that seem to have gone away now. For example, for a couple years, the truck has been pretty anemic going uphill at low speed with a bunch of people in the car. It would either crawl up the hill at about 1800 RPMs or if I pressed the pedal to the floor, it would roar up the hill. There was no in-between. Also I noticed that in the mornings or late in the evening when leaving for work that the engine would idle kind of rough. It wasn't terrible and it never threw a code, but it was enough that the dome lights would pulse with the vibration from the engine. Once everything warmed up, the vibration stopped and my lights stopped flickering. Post fuel pump change, I have a peppy drive up that hill, the rough idle is long gone and the lights never flicker anymore.