Sequential Multi-Port Fuel Injection (SFI)

WARNING: This page is about a different car, the 2007 Lincoln MKX and 2007 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Do not smoke or 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. Failure to follow these instructions may result in personal injury.

The fuel charging and controls system consists of the:

throttle body (TB).
fuel injectors.
fuel rail.

The fuel charging and controls system is:

a sequential multi-port fuel injection (SFI) system.
pulse width modulated (PWM).
mass air flow (MAF) controlled.

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 powertrain control module (PCM) by the MAF sensor, which 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.