Air Injection Pump: Description and Operation

The air injection pump injects air into the exhaust ports, where it combines with exhaust gases to continue the burning process, thereby lowering the levels of carbon monoxide and hydrocarbons entering the atmosphere.

The air bypass valve permits air from the injection pump to be routed to the exhaust ports during normal engine operation and to atmosphere during sustained high speed driving.

The vacuum differential valve prevents backfire during deceleration when triggered by a sharp increase in manifold vacuum by directing the air bypass valve to divert air to atmosphere.

The differential vacuum delay and separator valve delays the air bypass function during acceleration allowing air injection during initial acceleration and bypassing during sustained high speed operation--when high exhaust system temperatures can damage the catalytic converter.