2.2L Turbo Tests W/Codes: Description: Notes

NOTE: Information on this system is also covered in the FUEL SYSTEMS section. Additional diagnostic information that relates strictly to the fuel portion of this system can be found in the FUEL INJECTION SYSTEM - MULTI-POINT article in this section.

The computerized engine control systems used on 2.2L and 2.5L fuel injected engines control the fuel system, ignition system and emission control system for proper engine operation. Multi-Point Fuel Injection (MPFI) is used.

In order to control these systems, the computer monitors several engine and vehicle operating conditions. The engine conditions monitored include: manifold absolute pressure, throttle position, coolant temperature, charge temperature, manifold air temperature, exhaust gas oxygen content and vehicle speed/distance sensor.

Vehicle conditions monitored include vehicle speed and the status (off or on) of several vehicle systems that affect engine load. These include the transmission neutral safety, brake light and A/C clutch switches.

The Single Module Engine Controller (SMEC) controls the entire ignition system. The SMEC has a built in microprocessor that continually receives input from the engine monitoring sensors. The computer electronically advances and retards timing and adjusts the air/fuel mixture to provide even driveability and the most efficient fuel burn possible during operation.

Fig 1: Single Module Engine Controller (SMEC)

Fig 2: MPFI Turbo I & II Computer, Input Sensors & Output Devices