Closed Loop Mode

During this mode, EFC is operational and continuously corrects the air/fuel mixture toward 14.7:1 (best emission control ratio).

When the combustion computer receives signals from the oxygen sensor, and the throttle switch indicates the engine is not at idle, the computer sends a signal to the carburetor solenoid or vacuum regulator solenoid, causing the air/fuel ratio to be changed. This cycle repeats continuously to ensure proper mixture control at all times.

In addition, during the Closed Loop Mode, this system offers the built-in ability to maintain a constant air/fuel mixture regardless of altitude, because of its oxygen-sensing operation.