Fuel Injection Pump
The 300 Series have a connection from the turbocharger to the altitude compensator which allows that unit to enrich the mixture during boost operation.
The vacuum shut-off unit stops fuel delivery when the key is turned off. 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 injection pump. The pump is lubricated by engine oil.