3.0L CEC System: Description
The computerized engine control system used on 3.0L engine controls ignition timing, air/fuel ratio, emission control devices, cooling fan, charging system, idle speed, and cruise control for proper engine operation.
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, exhaust gas oxygen content, and vehicle speed.
Vehicle conditions monitored include the status of several vehicle systems that affect engine load. These include: transaxle neutral/safety, brake light, speed control, and A/C clutch switches.
The Single Module Engine Controller (SMEC) is the "brain" of the system. It is a digital programmed computer with an integral microprocessor. The SMEC processes all sensor inputs and assigns control signals to all output devices to control injector pulse width ("on" time), spark advance, idle speed, and other engine functions.