BMW E38 fuel pump not delivering
Why does the E38 not start even though there is petrol in the tank?
The tank has two halves, and the pump can suck air if its side is empty. Check the number of halves from the instrument cluster. Refuelling or tilting the car toward the pump side moves the fuel across. The cause can also be a cracked tank breather hose, which prevents the transfer.
How do I check why the pump is not running?
Check the pump relay and the fuses. The 730d's transfer pump relay is in the boot above the battery, and its fuses are F17 (10 A) and F57 (15 A). If the fuse gets no power, the cause can be the relay, the ignition switch base or the crankshaft position sensor.
Why does the fuel pump whine from the direction of the tank?
The pump is strained if the tank vent is blocked and vacuum builds up in the tank. A clogged fuel filter or a faulty pressure regulator also strains the pump. Check these before replacing the pump.
Can the transfer pump be installed wrongly?
Yes. If the pump is installed the wrong way round, it pumps fuel toward the tank instead of the engine. Check the installation direction if the engine gets no fuel after a pump replacement or tank work.