Fuel Injection

The injection pump is engine-driven by the same toothed belt that drives the camshaft. It handles virtually all engine fuel functions including pumping fuel from the tank, and controlling the timing and the quantity of fuel injected. A timing advance mechanism changes injection timing in response to engine speed and during cold-start conditions. Beginning in 1989, pumps have additional features that compensate for altitude changes and for different engine loads. The pump meters fuel to the injectors at an operating pressure in excess of 120 bar (1706 psi) and incorporates check valves to prevent backflow of fuel from the injectors. All the internal moving parts are lubricated by the diesel fuel, so routine maintenance is not required.