Fuel flow direction and fuel filter orientation

[bissellh]

I installed a used repacement fuel pump and a new fuel filter in my 1992 BMW 525i E34 M50. The pump is making some strange noises like it is strained and having to do too much work. Does anyone know the direction of fuel flow through the fuel lines back by the fuel filter? I want to check that I have the fuel filter oriented correctly. Also, does anyone know the direction of fuel flow through the fuel rail? Knowing that would help me trace the direction of fuel flow back to the fuel filter and would also help me relieve fuel pressure anytime I have to take off te fuel rail.

[colo525i]

Filter is easy, there should be a big black arrow showing the flow direction. it should be like this. (line from tank --- fuel filter (arrow------>)---rubber hose to hard line on body of car.

[bissellh]

Filter is easy, there should be a big black arrow showing the flow direction. it should be like this. (line from tank --- fuel filter (arrow------>)---rubber hose to hard line on body of car.

So the line coming down from the passenger rear of the car is coming from the gas tank and fuel pump. The filter is connected on the outbound fuel line not the return line from the fuel rail. The arrow on the fuel filter should point toward the fuel rail. Thank you! I knew about the arrow on the fuel filter. I guess I was uncertain if the fuel filter was on the out line or return line to/from the gas tank.

[colo525i]

Yes, the return line shouldn't have been disconnected (unless you had the pump out) there'd be an excess of rubber hose. For what its worth, i replaced my dented/vacuumed in tank with a good one, keeping the original pump and sender unit. The pump was incredibly loud, but the car ran fine. This eventually stopped, no idea why!

[bissellh]

I had to ask because my fuel pump is making humming noises for no apparent reason. I wanted to make sure that the fuel filter was oriented correctly. I replaced the fuel filter and oriented it the way it was recommended by your forum responses which is also the way the old one was oriented. The new fuel filter did not resolve the humming fuel pump though.

Thanks for the responses!

[colo525i]

Low sulphur gas may be making the pump a bit noisy. There are some upper cylinder lubes and other things you can add to the gas (nothing that'll hurt he engine) that will help the pump run more quietly. Hopefully someone will know the product names.