Air Injection System: Operation: Notes

The firing of the engine creates a pulsing flow of exhaust gases. Negative exhaust pressure (vacuum) causes the check valve to open and fresh air is drawn in and mixed with the exhaust gases.

Positive exhaust gas pressure forces the check valve closed. This valve action prevents exhaust gas from entering the fresh air supply lines.

Air supply to the check valves is controlled by vacuum operated air control valves. The vacuum supply to the valves is controlled by the air switching solenoids. These solenoids are controlled by the ECU.