System Description
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When ignition is turned on, the PCM will turn on the in-tank fuel pump. The in-tank fuel pump will remain on as long as engine is cranking or running and PCM is receiving ignition reference pulses. If there are no ignition reference pulses, PCM will turn the in-tank fuel pump off 2 seconds after the ignition is turned on or 2 seconds after engine stops running.
The in-tank fuel pump is an electric pump attached to the fuel sender assembly. The fuel pump is designed to provide fuel at a pressure above the pressure needed by the fuel injectors. A fuel pressure regulator, attached to the fuel rail, keeps the fuel available to the fuel injectors at a regulated pressure. Unused fuel is returned to the fuel tank by a separate fuel return pipe.