Computers and Control Systems: Description and Operation

The Computerized Engine Control system is built around a Feedback Carburetor Control Unit (FBC). The FBC constantly monitors return signals from various sensor inputs, then responds by opening or grounding a circuit within the control unit for an output device. As operating conditions change, the FBC unit makes adjustments to maintain optimum performance and fuel economy.
This vehicle uses an oxygen sensor to provide the FBC Unit with feedback control information concerning air/fuel mixture. The O2 sensor is threaded into the exhaust manifold above the Secondary Air Supply union. The Oxygen sensor detects the level of oxygen within the exhaust gases, compares it to the oxygen level of the atmosphere then, relays the input signal to the FBC unit. The FBC unit will either richen or lean the air/fuel mixture based on this signal input.


FBC INPUTS
^ Power Supply (Ignition Switch Coupled)
^ Power Supply (Battery Backup)
^ Engine Coolant Temperature Sensor
^ Throttle Position Sensor
^ Engine-speed Sensor
^ Oxygen Sensor
^ Secondary Air Control Vacuum Switch


FBC OUTPUTS
^ Feedback Solenoid Valve
^ Slow-cut Solenoid Valve
^ Throttle Opener Control Solenoid Valve (for A/C load)
^ Electric Choke Relay
^ Secondary Air Control Solenoid Valve