California Models

Fig. 60 Air Suction System Schematic:

The air suction (AS) system is used to direct air into the exhaust ports to extend the combustion of unburned hydrocarbons (HC) and carbon monoxide (CO) in the exhaust system. This air is also used as the oxygen source for the catalytic converter. Air flow is controlled by a valve assembly that includes a vacuum operated shut-off valve and a reed valve. During normal operation, the shut-off valve is held open by manifold vacuum. Vacuum created by exhaust pulses opens the reed valve and air is drawn into the exhaust stream. Manual transmission cars have a vacuum transmitter valve in the vacuum control line to slow application of the shut-off valve.