General System Description

FUEL SUPPLY COMPONENTS
The fuel tank stores the fuel supply. An electric fuel pump, located in the fuel tank with the fuel level sensor assembly, pumps fuel through an in-line fuel filter to the fuel rail assembly. The pump provides fuel at a pressure greater than is needed by the injectors. The fuel pressure regulator, part of the fuel rail assembly, keeps fuel available to the injectors at a regulated pressure. A separate pipe returns unused fuel to the fuel tank.


FUEL METERING SYSTEM COMPONENTS
The fuel metering system consists of the following parts:

^ The fuel supply components (fuel tank, pump, pipes).
^ The fuel pump electrical circuit.
^ The fuel rail.
^ The fuel injectors.
^ The fuel pressure regulator.
^ The throttle body.
^ The Idle Air Control (IAC) valve.
^ The Throttle Position (TP) sensor.

FUEL PUMP ELECTRICAL CIRCUIT
When the ignition switch is in the ON position (before engaging the starter), the PCM energizes the fuel pump relay for two seconds, causing the fuel pump to pressurize the fuel system. If the PCM does not receive ignition reference pulses (engine cranking or running) within two seconds, it shuts OFF the fuel pump relay, causing the fuel pump to stop.