buzzing noise form rear at idle

[Russell]

I just noticed a buzzing noise from the rear at idle when I am standing at the car. No vibration from floor of trunk or when I put my hand on the bottom of the gas tank.

Unless there are other sources, I am assuming the fuel pump is dying?? Wonder how much longer they last like this. From the archives on this board and other boards, some say they all do it while others say fix now! Are there any new thoughts on this? TIA

[shogun]

First you have to find out if it is eally the fuel pump.
Easiest way is to pull the fuel pump relay while engine is running.
It will still run a short time till it will starve due to low fuel pressure.
If the noise then stops, it will be the fuel pump.

But that does not mean at all that the fuel pump is at the end of it's life.
Maybe it just slipped out of it's bracket or something else broke in the fuel tank.
And some pumps whirr all their life.
Could also be some other vibration at the rear.
Start with the relay pulling first to eliminate one cause.
And to have a spare pump is always useful, otherwise you have to buy an expensive one from the dealer in emergency one day.

[Russell]

think I will try it this weekend. Looks like a spare pump will cost about $250 US.

[shogun]

$ 68,99 for a new pump
http://www.bimmerboard.com/forums/posts/358083

But I do not know if it fits perfectly and how the quality is. But the seller has a good positive result.
Maybe you contact them if that is a direct swop.