Diesel Injection Pump

High pressure diesel injection pump is mounted to top of engine below air crossover. Pump is cam driven at camshaft speed and can precisely govern time and amount of fuel injection.

Fuel entering the injection pump flows to the transfer pump and pressure regulator suction side. Fuel under transfer pressure now flows in 2 directions: to pressure side of pressure regulator, and to the head passage. The head passage will in turn divert fuel to the metering valve, pressure tap hole plug, advance mechanism, and the vent wire assembly.

The vent wire assembly allows air and a controlled amount of fuel to escape to the housing where it will flow back to the fuel tank via return oil circuit. Vent wire assembly consists of a screw with a hole through it into which a wire is positioned. Wire is free to vibrate and resist plugging by debris. Fuel from vent wire assembly circulates in the housing to cool and lubricate the internal pump components.

The metering valve controls fuel flow to pumping plungers. As pump shaft rotates, fuel is fired, under high pressure, through each delivery pipe to an injector. Pump is not serviceable and must be exchanged in case of a malfunction.