Fuel Pump: Description and Operation

The fuel pump is an electric pump that is controlled by the Powertrain Control Module (PCM) through the circuit opening relay. When the PCM commands the fuel pump to operate, an impeller is driven by an electric motor in the pump assembly, causing the fuel in the tank to be drawn into the fuel pump inlet port. The fuel is then pumped under pressure through the fuel filter and the fuel pressure regulator, out to the fuel feed pipe and hoses to the fuel rail and the fuel injectors. The fuel pressure is maintained when the fuel pump is not running by a pressure control valve located within the pump. Any excess fuel is returned to the fuel tank by the fuel return pipe and hoses.