4.0L MPI System: Description

The 4.0L engine control system controls engine operation to lower exhaust emissions while maintaining good fuel economy and driveability. The system is designed to maintain a 14.7:1 air/fuel ratio under all engine operating conditions. When the ideal air/fuel ratio is maintained, the catalytic converter can control oxides of nitrogen (NOx), hydrocarbon(HC), and carbon monoxide (CO) emissions.

The system consists of the following sub-systems: Fuel Control, Data Sensors and Switches, Electronic Control Unit (ECU), Diagnostics, Electronic Spark Advance, Idle Speed Control, Exhaust Gas Recirculation, and Transmission Shift Light.