Engine Control Module: Description and Operation

PURPOSE
The MCU monitors the oxygen sensor voltage and, based upon the mode of operation, generates a control signal for the carburetor stepper motor.

OPERATION
When the system is in the closed loop mode, the air/fuel mixture will vary according to the oxygen content in the exhaust gas and the engine operating conditions. When the system is in the open loop mode, the air/fuel mixture will be based on a predetermined ratio that is dependent on several engine operating conditions.