Computers and Control Systems: Description and Operation

This system is used on 1983 4-151, 1983-85 4-150, some 1986 4-150 and 1983-87 6-258 engines. It controls the air/fuel ratio and air injection systems through the use of various sensors which are controlled by the Micro Computer Unit (MCU). The 1983-87 CEC system, used on the 6-258 models, also use a stepper motor which is an integral part of the model BBD carburetor. The 1983-86 4-150 and 6-258 engine CEC system, differs in that the distributor signal is first received by the MCU, then routed to the ignition system Electronic Control Unit (ECU). Also, this system uses the Carter YFA carburetor which incorporates a Mixture Control (MC) solenoid to control the air/fuel ratio by metering airflow to the carburetor.