The BMW 320D is a sedan which was designed to generate goodwill towards diesel automobiles by eliminating the typical noise and noxious exhaust of diesel engines. The 320D uses the Bosch VP 44 fuel injector pump. However, there have been some issues with the VP 44.
One main cause of failure in the fuel pump is the electronic diesel control unit (EDU). This component is mounted on the top of the pump. The EDU can develop bad connections because of exposure to heat. The results are drivability problems, such as hard starting and white exhaust smoke.
Fuel Pressure Weakness
The second problem with the VP44 is low fuel pressure, which is caused by insufficient fuel flow from the transfer pump. This occurs after several hours of operation with low fuel pressure. The VP44 is lubricated by fuel. If there is insufficient fuel flow or lubrication, the injector pump life is shortened.
Seizing of the rotor in the distributor is another problem with the fuel pump. This is caused by fuel pressure which is higher than the manufacturing variances allow. The rotor interferes with the distributor which results in binding of the rotor and distributor. The result is the vehicle cannot start.