General System Description

Fuel System Functions
The fuel system has two main functions, fuel supply and fuel metering.

Fuel Supply System
The function of the fuel supply system is to supply the right amount of fuel at the correct pressure to the fuel injectors.

Fuel Delivery
The fuel supply is stored in the fuel tank. An electric fuel pump, attached to the fuel sender assembly, pumps fuel through an in-line fuel filter to the fuel rail and injectors. The pump is designed to provide fuel at a pressure above the regulated pressure needed by the fuel injectors. A pressure regulator keeps fuel available to the injectors at the proper pressure. Unused fuel is returned to the tank by a separate hose and pipe.

Fuel Metering
The function of the fuel metering system is to control the amount of fuel to the engine under all operating conditions. Fuel is delivered by four injectors in the intake manifold near the cylinder intake ports.

Feedback Control
The amount of fuel being injected into each cylinder is closely monitored and modified by the ECM/PCM. The ECM/PCM modifies the air/fuel mixture by changing the injector pulse width signal sent to the injectors. By constantly measuring the exhaust gas oxygen content and adjusting the injector pulse width, the air/fuel ratio is kept very close to the optimal 14.7:1. This is the range at which the catalytic converter operates most effectively.