Feedback Carburetor System: Operation: Notes

During engine start-up, warm-up operation, high load operation and deceleration, the air/fuel ratio is open loop controlled by values established previously for engine speed, throttle valve angle and coolant temperature. After engine warm-up, air/fuel ratio control is made by closed loop control, based on oxygen sensor signal. The ECU controls air/fuel mixture by controlling the Feedback Solenoid Valve (FBSV) and the Slow-Cut Solenoid Valve (SCSV) mounted on the carburetor.