Fuel Injection Pump
The Bosch VP-20 fuel injection pump used on BMW 2.4L diesel engine is controlled by an electronic control assembly mounted in the luggage compartment. The control assembly processes information from the engine coolant temperature sensor, the position sensor and the lift sensor located in the No. 4 injector. Control assembly varies the injection timing according to this information. To change the injection timing, the control assembly controls the cycling of the fuel control solenoid in the injection pump. The solenoid varies the fuel pressure available to the advance piston by providing an additional pressure bleed and pressure at the advance piston. It therefore controls injection timing. The amount of fuel injected into the cylinders is not affected by the solenoid. The system has a built-in diagnostic capability which will light the "CHECK TURBO" warning indicator when there is a problem in the system.