4.2L Feedback Carburetor Testing: Description
The Computerized Emission Control (CEC) system is used on all 6-cylinder engines. It is an electronically controlled system that manages the air/fuel ratio and controls ignition timing, idle speed, and the pulse air injection system.
The primary objective of the CEC system is to maintain an ideal air/fuel ratio of 14.7:1 under all operating conditions. When the ideal air/fuel ratio is maintained, the catalytic converter can effectively control CO, HC and NOx emissions.