BMW e38 740iL Fuel Pump Noise/Whine

[Auto Parts Guy]

I have this very loud whining noise coming from the fuel pump on my 2001 740iL. I have already replaced PN 16141182193, the white valve inside the passenger side of the tank. It didn't make a difference unfortunately. There is no change in pressure when i remove the fuel cap with the car running, no change at all. There are no codes in INPA. So my only thought is the fuel pump? But i see some people replace the pump and that doesn't fix it either. Any suggestions? She drives great with plenty of power, no other symptoms other than this annoying and embarrassing fuel pump whine.

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[Mayorchuck]

If it were mine, I would remove the cap under the seat, trip the fuel pump relay to kick on the pump and listen. It should be obvious is the sound is right there. You could even pull up the pump while using the relay to kick it on to be sure. Tim shows how to do it in the link below. I've done this many times, even without a key, to drain the gas on a parts car.

https://www.bimmerforums.com/forum/s...9#post25248449

[Auto Parts Guy]

I am 99.999% sure that the fuel pump is making the noise, just not sure why. Guess it's time to throw a new pump in and see what happens. Just weird that everything runs great. Almost seems like an isolator is missing or something, like it's vibrating throughout the tank and car..

[tomloans]

What Mayorchuck said. Also pop the back seat up and if it is whining as much as you say, you should easily hear it with the seat off dont you think.

[Auto Parts Guy]

Yes, of course I have already done this. Did it before I replaced that white check valve. The question isnt is the noise coming from my fuel pump. It's why. And will a new pump fix it? Or is there another remedy? I've never had a pump make such loud noise before going out. Ive Put more than 200 miles on the e38 with this loud whine and I can't stand it any longer. Not a fan of chunking parts at a problem, but not sure what else could be making the pump whine like this.

[tomloans]

Yes, of course I have already done this. Did it before I replaced that white check valve. The question isnt is the noise coming from my fuel pump. It's why. And will a new pump fix it? Or is there another remedy? I've never had a pump make such loud noise before going out. Ive Put more than 200 miles on the e38 with this loud whine and I can't stand it any longer. Not a fan of chunking parts at a problem, but not sure what else could be making the pump whine like this.

There is also the possibility of the mechanical jet pump that is spoken of in these forums. Apparently this pumps fuel from one side of the tank to the other. I couldn't find this part on REalOEM.com so take this comment with a grain of salt. Well if the fuel pump has never been changed, why not.

My M5 pump suddenly died on a very busy freeway in 110 degree weather. That was a day I will not forget. At least this one is giving you a warning.

[Auto Parts Guy]

Yeah i thought about that. I'll stick my stethascope on each side to be sure. But it's way louder on the passenger side. I'm just going to pick up a pump and try it out i guess.

[Mayorchuck]

There is nothing mechanical in the E38 tank other than the pump.

[Auto Parts Guy]

Just a quick update:
The new pump fixed the noise issue. I looked over the old pump but didn't see anything obviously wrong with it. The rubber isolators were still intact. I guess it was just going out. Either way, the new one fixed the whining noise! Replacement is pretty straight-forward.

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[Auto Parts Guy]

I took another look at the old pump today and I think the filter was just super clogged causing the pump to work extra hard. So for anyone else in this situation, maybe try a new pump filter first.


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