Feedback Carburetor System

The system operates the engine on leanest possible fuel mixture. During normal engine operation air/fuel mixture is controlled through fuel metering. Fuel metering is accomplished by the use of 3 solenoid operated on/off valves. The 3 valves (jet mixture, enrichment and deceleration) add or reduce the amount of fuel supply to the engine. Activation of on/off valve is controlled by length of time electrical current is supplied to solenoid. See Figure .

Each solenoid operates at a fixed frequency. By varying the amount of time the solenoid is energized during the duty cycle, the air/fuel mixture to the engine can be precisely controlled. The duty cycle for each solenoid is controlled by the Electronic Unit (ECU) in response to signals from the vacuum switch, exhaust oxygen sensor, throttle position sensor, coolant temperature sensor, engine speed sensor and intake air temperature sensor.