Sequential Multi-Port Fuel Injection (SFI)

Fuel Charging and Controls

Sequential Multi-Port Fuel Injection (SFI)

System Overview

WARNING: Do not smoke, carry lighted tobacco or have an open flame of any type when working on or near any fuel-related component. Highly flammable mixtures are always present and may be ignited. Failure to follow these instructions may result in serious personal injury.

The fuel charging and controls system is:

- a Sequential Multi-Port Fuel Injection (SFI) system.

- Pulse Width Modulated (PWM).

- Mass Air Flow (MAF) sensor controlled.

Component List

The fuel charging and controls system consists of the:

- Throttle Body (TB)

- fuel injectors

- fuel rail

- Fuel Pump Control Module (FPCM)

System Components

Throttle Body (TB)

The TB (Throttle Body) :

- controls air supply to the intake manifold by electronically positioning the throttle plate.

- is not adjustable.

- cannot be cleaned.

Fuel Injectors

The fuel injectors:

NOTICE: Handle the fuel injectors and fuel rail with extreme care to prevent damage to sealing areas and sensitive fuel-metering orifices.

- are electronically operated by the PCM.

- atomize the fuel as it is delivered.

- each have an internal solenoid that opens a needle valve, injecting fuel into the intake port in the cylinder head.

- are deposit resistant.

Fuel Rail

The fuel rail receives fuel from the fuel supply tube and delivers fuel to the fuel injectors.

NOTICE: Handle the fuel injectors and fuel rail with extreme care to prevent damage to sealing areas and sensitive fuel-metering orifices.

Fuel Pump Control Module (FPCM)

The FPCM (Fuel Pump Control Module) is electronically operated by the PCM and controls voltage to the Fuel Pump (FP) depending on engine load.

System Operation

Fuel is metered into each intake port in a sequential firing order. Fuel injectors pulse to follow engine firing order, in accordance with engine demand on a tuned intake manifold.

The basic fuel requirement of the engine is determined from the data supplied to the PCM by the MAF (Mass Air Flow) sensor. The MAF (Mass Air Flow) sensor measures the amount of air being drawn into the engine.

The various sensors detect any changes in the operating conditions and send signals to the PCM. This permits the PCM to control the opening duration (pulse width) of the fuel injectors and maintain optimum exhaust emission control and engine performance for all operating conditions.