: Strange noise from rear of car



carguy16
03-25-05, 07:43 PM
For some reason, when the engine is running, there is a strange low pitched noise that can be heard from the rear of the car, inside or outside.

With the A/C, lights and radio off, and foot off the brake, I can hear it on. When the 4 ways were on one day, and I was outside, it was in sync with the 4 ways, when the 4 ways would activate, it would get louder, when they went off it would quiet down.

Today, I could hear it inside the car. I shut the engine off, and turn the ignition to run(engine was off), the noise stopped. Anyone know what this is? Im really curious.

cad_90
03-25-05, 08:03 PM
Sounds like it might be your fuel pump.

As soon as you turn the key to start the engine, it is active and circulating fuel from the tank to the fuel rail and back.

When I was restoring the interior of my 1990 Deville, I would hear the same thing you are describing, but only on the inside. This was because the carpet, padding, seats, etc... were all removed. Now that the car is back together I do not hear it.

In your case, the fuel pump motor, (which is inside the fuel tank directly under the rear seats), may be malfunctioning and making more noise than it should.

carguy16
03-25-05, 08:25 PM
Something I should check into, I will see what fuses go where. I know my tank is also approaching empty right now, but I really havnt thought much about it before.




Sounds like it might be your fuel pump.

As soon as you turn the key to start the engine, it is active and circulating fuel from the tank to the fuel rail and back.

When I was restoring the interior of my 1990 Deville, I would hear the same thing you are describing, but only on the inside. This was because the carpet, padding, seats, etc... were all removed. Now that the car is back together I do not hear it.

In your case, the fuel pump motor, (which is inside the fuel tank directly under the rear seats), may be malfunctioning and making more noise than it should.

ocjmakaveli
03-25-05, 08:26 PM
don't jump to conlusions but if you hear a Whining noise near your gas tank then it is your fuel pump i had this problem on my 2000 suburban with only 50,000 miles.

If you let the gas tank run low frequently the pump tends to overheat and wear out quick.

juiceE
03-28-05, 11:55 AM
I've Noticed In The Fwb That When Im Driving On Really Low Tank (nlinking Light) With Radio Off An Really Quiet, Ill Hear A High Pitched Whine, An It Only Happens When Im Really Low On Gas, I Just Never Leve It Low Any More :yup:

N0DIH
03-28-05, 01:32 PM
For some reason, when the engine is running, there is a strange low pitched noise that can be heard from the rear of the car, inside or outside.

With the A/C, lights and radio off, and foot off the brake, I can hear it on. When the 4 ways were on one day, and I was outside, it was in sync with the 4 ways, when the 4 ways would activate, it would get louder, when they went off it would quiet down.

Today, I could hear it inside the car. I shut the engine off, and turn the ignition to run(engine was off), the noise stopped. Anyone know what this is? Im really curious.

If you turn the ignition on, but not start, does it go on for a sec or 2 then stop? And if you cycle the ignition, does it do the same again?

That is the fuel pump for sure. Turn radio off to ensure it isn't the power antenna motor going up and down.

drc3x
08-25-05, 07:09 PM
My 95 Eldo with 108,000 has a hum also coming from the fuel pump. This started after I had the recalled fuel rail replaced. Would I get a code if it was about to fail? Could a clogged fuel filter do this as in some other models?
:horse: .

ocjmakaveli
08-26-05, 12:30 PM
My 95 Eldo with 108,000 has a hum also coming from the fuel pump. This started after I had the recalled fuel rail replaced. Would I get a code if it was about to fail? Could a clogged fuel filter do this as in some other models?
:horse: .

no code and no the fuel filter wont cause the pump to fail but it can be a cause of insufficient fuel getting to the injectors and the injectors can clog up in case the filter is plugged up letting dirt get to the injectors

N0DIH
08-26-05, 12:41 PM
The injectors have thier own screen, which can get plugged up. But honestly I have never seen one get plugged.

When my 91 Bonneville fuel pump got weak (30 psi and then started to drop ovr time) it would run ok, but a little difficult to start, it would die easy when cold, then it started getting worse and worse trying to take off (buck), then it got to a point it was very difficult to accelerate (would buck and backfire if you pressed too hard)

A fuel pressure gauge is one of my favorite tools next to a hand held vacuum pump. I highly recommend it. It eliminates a lot of expensive guess work.