Circuit Description

When ignition switch is turned on, PCM will turn in-tank fuel pump on. In-tank fuel pump will remain running as long as engine is cranking or running and PCM is receiving 58X crankshaft position pulses. If there are no 58X crankshaft position pulses, PCM will turn in-tank fuel pump off 2 seconds after ignition switch is turned on, or 2 seconds after engine stops running. In-tank fuel pump is an electric pump within an integral reservoir. In-tank fuel pump supplies fuel through an in-line fuel filter to fuel rail assembly. Fuel pump is designed to provide fuel at pressure above pressure needed by fuel injectors. Fuel pressure regulator, attached to fuel rail, keeps fuel available to fuel injectors at a regulated pressure. Unused fuel is returned to fuel tank by a separate fuel return line.