Circuit/System Description

The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within 2 seconds unless the control module detects crankshaft reference pulses. The control module continues to enable the fuel pump relay as long as crankshaft reference pulses are detected. The control module disables the fuel pump relay within 2 seconds if crankshaft reference pulses cease to be detected and the ignition remains ON.

The fuel tank stores the fuel supply. An electric fuel pump attaches to the fuel pump module inside the fuel tank. Fuel flows to the fuel filter/heater element housing, which combines a water separator, fuel heater element, and a filter element. The fuel is then delivered to the high-pressure pump. The mechanical fuel injection pump is located at the front of the engine. The mechanical fuel injection pump is engine-driven by the timing belt. From the high-pressure pump, the pressurized fuel flows to the fuel rail. The fuel rail is equipped with a fuel rail pressure sensor and a fuel pressure regulator.

The Fuel Return System returns un-used fuel to the fuel tank. Fuel is used to cool and lubricate the fuel injectors and fuel injection pump. If the high side fuel pressure becomes excessive, the fuel pressure regulator releases the fuel into the fuel return system. The return fuel travels through the fuel lines and then to the fuel tank.