General System Description

PURPOSE
The computer control system used on this engine consists of sensors which detect various engine conditions and an Engine Control Module (ECM) which controls fuel injection timing, self diagnostic function, ignition timing control, idle speed control, and various other functions.

OPERATION
The computer control system controls these operations in the following manner;

Multiport Fuel Injection
The ECM receives signals from various sensors indicating changing engine operating conditions such as; intake air volume, engine speed, intake air temperature, acceleration/deceleration, engine coolant temperature, exhaust oxygen content etc.. These signals are utilized by the ECM to determine the injection duration necessary for an optimum air-fuel ratio.

Electronic Spark Advance
The ECM is programmed with data for optimum ignition timing under all operating conditions. Again, using data provided by sensors which monitor various changing engine conditions the ECM triggers the spark at precisely the right instant.

Diagnosis Function
When the ECM detects a malfunction or abnormalities in the sensor network, it lights the Malfunction Indicator Lamp in the Combination Meter. At the same time, the trouble is identified and a Diagnostic Trouble Code is recorded by the ECM. The Diagnostic Trouble Code can be read during troubleshooting to help determine the faulty component and/or system.

Emissions Control
The ECM, also by processing input from various sensors, controls the functions of the Evaporative Emissions System and the Exhaust Gas Recirculation System to maximize both emission control as well as driveability.