Buzzing Fuel Pump ????

[HAL BAUGUSS]

Is a loud pronounced "buzz" from the fuel pump a sign of impending death? This is on a 91 560 SEL with 175000 miles. I have heard pumps before but you had to be down under the car to hear the buzz. You can hear this one from 15-20 feet away from the car! Any comments or experience with this. Thanks to all.

[Snibble]

I too get this sometimes from my car.. but it has not done anything. It has a new fuel filter and that took care of the stalling problem i once had a while back.*knock on wood*

[drbrandini]

I have always had a notable note coming from the fuel pump on all my late model MB's, I think your Ok...(Notable not loud) ...

[ymsin]

I was told that the louder the buzz (BUZZZ), it would be a matter of time before the pump KOs.

[ymsin]

Being a staunch believer that MB builts the best cars and parts, I do hope that pumps (no matter the Buzz) will go on for years and years ...

Being a perfectionist and a tad fussy when it comes to my stable of cars, the Buzzy pump had to be replaced for fear that it would one day stop buzzing altogether. The new pump has less Buzz that is almost unnoticeable.

I have to add that prior to the replacement, the buzz was softer on start, and louder when driven long distance ....

[anthonyb]

If I remember correctly, one way to diagnose a dying pump is to check current flow at the fuel pump relay socket: remove relay, bridge the pins for the pump, and read amps. I believe max allowable is somewhere around 6-8 amps, but it varies by model and year. Too much current draw will kill the relay, so more important is if the relay is busted (non-start or stalling), check current draw before installing new one.

fyi - all of our cars have the original fuel pumps in them (knock on wood).

-anthony