Fuel System

WARNING: DO NOT SMOKE, CARRY LIGHTED TOBACCO OR OPEN FLAME OF ANY TYPE WHEN WORKING ON OR NEAR ANY FUEL-RELATED COMPONENT. HIGHLY FLAMMABLE MIXTURES ARE ALWAYS PRESENT AND MAY BE IGNITED, RESULTING IN POSSIBLE PERSONAL INJURY.

Components

The fuel delivery subsystem consists of:

^ a high-pressure, in-tank mounted, electric fuel pump.

^ a fuel filter/reservoir delivering fuel from the fuel tank.

^ a 20-micron fuel filter.

^ fuel supply and return tubes.

Operation

^ the fuel injection supply manifold which incorporates an electrically-actuated fuel injectors directly above each of the engine's intake ports.

^ the fuel injectors which, when energized, sprays a metered quantity of fuel into the intake air system.

A constant fuel pressure drop is maintained across the fuel injectors by a fuel pressure regulator. The fuel pressure regulator is:

^ connected in series with the fuel injector.

^ positioned downstream from fuel injectors.

Excess fuel supplied by the fuel pump, but not required by the engine, passes through the fuel pressure regulator and returns to the fuel tank through a fuel return line.

Fuel injection timing is accomplished through the following:

^ each fuel injector is energized once every other crankshaft revolution in sequence with firing order.

^ the period of time that the fuel injectors are energized (fuel injector on time or pulse width) is controlled by the vehicle's powertrain control module (PCM).

^ air entering the engine is monitored by flow and temperature sensors.

^ the outgoing signals of the electronic engine control sensors are processed by the powertrain control module.

^ the powertrain control module determines the needed fuel injector pulse width and sends a command to the fuel injectors to meter the exact quantity of fuel.