Pulsair Valve: Description and Operation

PAIR Valve:

OPERATION
The PAIR valve sends secondary air to the exhaust manifold, using a vacuum created by exhaust pulsation in the exhaust manifold. When the exhaust pressure is below atmospheric pressure (negative pressure), secondary air is sent to the exhaust manifold. When the exhaust pressure is above atmospheric pressure, the reed valves prevent secondary air from being sent back to the air cleaner.
The PAIR valve is controlled by the ECM (ECCS control module), corresponding to the engine coolant temperature. When the engine is cold, the PAIR valve control system operates to reduce HO and CO.
In extremely cold conditions, PAIR valve control system does not operate to reduce after-burning. This system also operates during deceleration for the purpose of blowing off water around the PAIR valve.