GM Service Manual Online
For 1990-2009 cars only

The following are the main components of the vehicle's sequential fuel injection (SFI) system:

    • The throttle body assembly
    • The fuel injectors
    • The fuel pressure regulator
    • The fuel rail assembly
    • The fuel pump
    • The fuel tank
    • The fuel filter
    • The fuel feed pipes and hoses
    • The fuel return pipes and hoses

The supply of fuel is stored in the fuel tank. An electric fuel pump pressurizes the fuel through an in-line fuel filter to a fuel rail assembly that supports the fuel injectors. The electric fuel pump is located in the fuel tank. The fuel pump is designed to provide fuel at pressures and volumes greater than that needed by the fuel injector. A fuel pressure regulator located on the fuel rail keeps the fuel supplied to the fuel injectors at the regulated pressure. The regulated pressure is always kept higher than the pressure in the intake manifold. Unused fuel is returned to the fuel tank by a separate return pipe and hose.

The fuel injectors opens according to injection pulse signals from the powertrain control module. The fuel is injected into the intake ports in a cone shaped (conic) dispersion pattern.

The engine is designed to use only unleaded fuel. Unleaded fuel must be used for proper emission control system operation. Using unleaded fuel will also decrease spark plug fouling and extend engine oil life. Leaded fuel can damage the emission control system. The use of leaded fuel can result in the loss of emission warranty coverage.

This vehicle's fuel system is equipped with an evaporative emission control system that minimizes the release of fuel vapors to the atmosphere. For more information on this system, refer to EVAP Control System Operation Description .