Air Injection System: XJS
The air pump supplies air under pressure through a diverter valve, check valve, and air rails to the exhaust ports just above exhaust valves. The air combines with exhaust gases to further the burning of hydrocarbons and carbon monoxide. Check valve prevents exhaust flow into air rails when exhaust pressure exceeds air supply pressure.
Diverter valve operates in response to abrupt increase in manifold vacuum and diverts secondary air to atmosphere for 2-3 seconds. The valve senses sudden increases in intake manifold vacuum and diverts air away from exhaust system. This prevents combining of unburned fuel mixture with secondary air and becoming combustible in the exhaust, creating a backfire.