Fuel Injection Pump
All models use the same type of injection pump, though 5-cylinder models have one more pump element. Turbo models have a connection from the turbocharger to the altitude compensator which allows the unit to enrich the mixture during boost operation.
Fuel pump must deliver under certain pressure and without air bubbles. Insufficient pressure can cause engine problems. The pressure is kept constant by a by-pass valve which is installed in main fuel filter and opens at pressures between 14.7-22.0 psi (1.03-1.50 kg/cm2 ).
The vacuum shut-off stops fuel delivery when the ignition switch is turned to the "OFF" position. If it fails, a manual "STOP" lever is provided on the side of the pump. A mechanical fuel pump draws fuel from the tank and supplies it to the high pressure section of the injector pump. The pump is lubricated by engine oil.