Fuel Delivery and Air Induction: Description and Operation

Fig. 1 Fuel injection nozzle:

Fig. 2 Fuel injection pump circuit. V8 engine:

Fig. 3 Fuel injection pump circuit. V6 engine:

The fuel injection pump is mounted on top of the engine and is gear driven by the camshaft and rotates at camshaft speed. This high pressure rotary pump injects a metered amount of fuel to each cylinder at the proper time. Six or eight high pressure fuel delivery pipes from the injection pump to the injection nozzles, Fig. 1, are the same length to prevent any difference in timing from cylinder to cylinder. The fuel injection pump provides the required timing advance under all operating conditions. Engine speed is controlled by a rotary fuel metering valve, Figs. 2 and 3. When the accelerator is depressed, the throttle cable opens the metering valve and allows more fuel to be delivered to the engine. The injection pump also incorporates a low pressure transfer pump to deliver fuel to the fuel line to the high pressure pump, Figs. 2 and 3.

The fuel filter is located between the mechanical fuel pump and the injection pump on 8 cylinder engines, or between the electric fuel pump and the injection pump on 6 cylinder engines. The diaphragm type mechanical fuel pump used on 8 cylinder engines is mounted on the righthand side of the engine and is driven by a cam on the crankshaft. The electric fuel pump used on 6 cylinder engines is mounted on the engine. The fuel tank at the rear of the vehicle is connected by fuel pipes to the mechanical fuel pump.