there was a humming noise come from the back seat area... so suspected the fuel pump and put in a nea one... But the noise did not go away. I then changed the fuel sending unit on the left side because the noise seemed to be coming from there. But the noise did not go away... Before doing anything else I want to know what else should I check... or what else could it be that is causing that noise
Rear wheel bearing?
Diff - is the noise worse in reverse or sharp corners? This can often be ignored - I had one whirr in reverse for 11 years until I sold the car.
It's the fuel pump.
Just because you can hear the pump does not mean anything.
it makes the noise while standing still and the transmission in park. I dont think it the bearing.
the noise it just there all the time. 10 seconds after starting the car the noise starts up.... It is coming from the gas tank area. And is muffled a little when the sound deadening pad is replace onto the fuel pump access cover plate. but its there even in park
I replaced the old fuel pump with a new one already and the new is still there. The pump that is in there now is only 3 days old
If the noise starts when you turn the key on, it's the pump. If the noise does not start until you are driving, then it could be the diff.
Does it make the sound with the gas cap off? You can sometimes get funny noises from the tank venting system.
If it is the fuel pump, it will usually be much louder when the tank is low than when the tank is full.
Some fuel pumps are just noisy. Life is like that.
--scott
Fuel pump then - look for a leak and bleed the line.
Is there any sort of a pressure switch which should switch it off once satisfactory pressure is achieved?
PS my third 735i used to whirr for a few seconds after switch on while it pressurised the fuel line - it was best to wait for this to end before trying to start the engine.
CD player back there gone bad?
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.