Gasoline engines
Note: On diesel engines, the fuel pressure is measured in the fuel line between the filter and the high pressure fuel pump, which can only be carried out at a workshop.
The test condition is a normally charged battery.
Models 3161, 318i before August 1993: 4 - fuel return hose.
Models 316i, 318i since September 1993: The fuel hose is located in the appropriate location under the intake pipe. 2 = fuel return hose.
Models 320i, 325i, 328i: 6 = fuel return hose.
Disconnect the fuel return hose from the distribution pipe and lower the hose into a measuring vessel with a capacity of approx. 2 liters).
Pull out the fuel pump relay. The fuel pump relay is located in the relay box at the left rear of the engine compartment.
Bridge terminals 30 and 87b (on diesel engine terminal 87) on the relay site with a short jumper with a diameter of 1.5 mm and start the fuel pump for about 30 seconds.
In 30 seconds, the amount of fuel supplied should be about 1 liter. In this case, the consumption of the fuel pump is 5.5 amperes.
If less fuel is supplied, replace the fuel filter and check pump performance again. If performance continues to be poor, replace the fuel pump.