Pulsair Valve: Description and Operation

Fig. 35 - PAIR System Hose Routing:

The PAIR system--Fig 35, used on some vehicles consists of four pulse air-check valves connected to the exhaust ports.

As the engine fires positive and negative pressure pulses are created in the exhaust system.
- Negative pressure pulses pull fresh air through the check valves into the exhaust system.
- Positive pressure pulses close the check valves, preventing exhaust gas from entering the fresh air supply lines.

Fig. 6 - Deceleration Valve:

Deceration Valve
The deceleration valve--Fig 6--used on some 1981-82 vehicles--prevents backfiring in the exhaust system during deceleration by supplying the additional oxygen needed to burn the fuel supplied.
- When the throttle valve closes on deceleration manifold vacuum increases abruptly, the pressure differential on the diaphragm overcomes spring tension, opening the valve and bleeding air into the intake manifold.
- Air trapped in the chamber above the vacuum diaphragm will be bled at a calibrated rate through the delay valve portion of the integral check and delay valve, reducing vacuum on the diaphragm.
- When vacuum on the diaphragm and spring tension become equal, the valve closes and cuts off air supply to the intake manifold.
- The check valve portion of the check and delay valve provides a rapid balancing of chamber pressure when there is a sudden decrease in vacuum during acceleration.