Fuel Delivery System

PURPOSE
The basic function of the fuel system is to control fuel delivery to the engine under all operating conditions.

FUEL SYSTEM COMPONENTS
The Multiport Fuel Injection (MFI) system consists of the following parts:

- Fuel supply system (fuel tank, pump, pipes).
- Fuel pump electrical circuit.
- Intake manifold assembly, consisting of:

- Lower manifold assembly, including:

- MFI fuel injectors.
- Fuel pressure regulator assembly.

- Upper manifold assembly, including:

- Throttle valve.
- Idle Air Control (IAC) valve.
- Throttle Position (TP) sensor.

Intake Manifold Assembly:

BASIC SYSTEM OPERATION
The fuel supply is stored in the fuel tank. An electric fuel pump, located in the fuel tank with the gage sending unit, pumps fuel through an in-line fuel filter to the lower manifold assembly fuel passage. The pump provides fuel at a pressure greater than is needed by the injectors. The pressure regulator, attached to the end of the lower manifold assembly, keeps fuel available to the injectors at a regulated pressure. Fuel, in excess of injector needs, is returned to the fuel tank by a separate return line.