Dying fuel pump whine - with new pump.

[crappycoco]

1988 325is

There is this "dying fuel pump whine" that's present all the time when the car is running. The pitch goes up and down together with rpm. The thing is, I've just replaced the fuel pump with a brand spanking new one, new fuel filter and checked the fuel pressure which was 43psi. Vacuum tube at FPR is dry as a bone. If anyone has an idea what could be causing this, please let me know.

I've shot a video to help with diagnosing =)

[dnguyen1963]

Did you re-use the fuel line connector? If yes, I would remove it and just use two pieces of injector fuel line and hose clamps to reconnect the pump.

[crappycoco]

Forgive my ignorance, but what fuel line connector? There was just a hose which came from the fuel line to the pump.

Very much like this:

[dnguyen1963]

The part in the picture of this link connecting the pump to the fuel line.

http://www.ebay.com/itm/like/320539086243?lpid=82

The original BMW pump is shown below. The white connecting part is the one that can make noise as it gets old and loose.

http://www.ebay.com/itm/BMW-OEM-Fuel-Pump-In-Tank-Suction-Device-E30-16-14-1-179-992-16141179992-/261656239061?pt=Motors_Car_Truck_Parts_Accessories&hash=item3cebed5bd5&vxp=mtr

[crappycoco]

Hm, I've changed the whole assembly so it should be new. The whole assembly came new with everything. I just took the old one out and swapped in the new one. I should probably mention its not a oem pump, its aftermarket, but i dont know if its supposed to make so much noise?

[dnguyen1963]

Which pump did you buy? AirTex pump can be a crap-shoot.

[crappycoco]

Aw crap. That's exactly what I bought. I'll have to ask If I can return it or something. Which makes are better quality? Or do I go and just buy oem?

[crappycoco]

@dnguyen1963 could it be the auxiliary pump making the noise? Because the noise is only there when the car is running, not when its "priming".

[dnguyen1963]

The noise is coming from your tank so it is the transfer pump. Look up Tre pump. They are relative inexpensive and as good as OEM.

[crappycoco]

thanks! i guess I'll have to change the pump too now =)

[crappycoco]

Changed the pump for OEM. Works like a charm + I have even better fuel pressure now. Airtex pump was the culprit as it seems.