Combination Valve

The combination valve is located toward the front of the engine above the exhaust manifold. The combination valve consists of two valves. The uppermost valve, a spring loaded diaphragm, is opened by vacuum which is regulated by the air pump solenoid. The lowermost valve, a reed valve, is opened by air pressure from the air pump. The reed valve helps prevent exhaust gas from recirculating back toward the pump. Air from the air pump flows through the diaphragm and reed valve to the exhaust manifold.