Sequential Multiport Fuel Injection (SFI) and PCM

The 1.8L DOHC engine relies on a sequential multi port fuel injection (SFI) system to supply the engine with the correct air/fuel mixture. The air induction system and fuel injection system work in conjunction with an electronic engine control system which consists of various sensors, switches, and a Powertrain Control Module (PCM). All sensors and switches are connected to the PCM, which interprets the data it receives and computes the timing and the duration of the electrically operated injectors.

The basic fuel requirement of the engine is determined from the data supplied to the PCM by the mass air flow (MAF) sensor, which measures the amount of air being drawn into the engine.

Other sensors and switches are used to measure:
a. Air temperature
b. Barometric pressure
c. Coolant temperature
d. Engine speed
e. Exhaust oxygen content

The various sensors and switches 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 injectors and maintain optimum exhaust emission control and engine performance for all operating conditions.