2005 Pontiac Grand Prix

Should my air injection pump run all the time when the engine is running and if not, what controls its operation? Will it burn out if it runs all the time?

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  1. Secondary air injection (commonly known as air injection, or colloquially smog pump) is a vehicle emissions control strategy introduced in 1966, wherein fresh air is injected into the exhaust stream to allow for a fuller combustion of exhaust gases. An implementation of the system has been trademarked by the name Air Injection Reactor (A.I.R.).

    Pumped air injection systems use a vane pump turned by the engine via a belt. The pump’s air intake is centrifugally filtered by a rotating screen to exclude dirt particles large enough to damage the system. Air is delivered under pressure to the injection point(s). A check valve prevents exhaust forcing its way back through the air injection system, which would damage the pump and other components.

    Carbureted engines’ exhaust raw fuel content tends to spike when the driver suddenly releases the throttle. To prevent the startling and potentially damaging effects of the explosive combustion of this raw fuel, a diverter valve is used. This valve senses the sharp increase in intake manifold vacuum resulting from the sudden closure of the throttle, and diverts the air pump’s outlet to atmosphere. Usually this diverted air is routed to the engine air cleaner or to a separate silencer to muffle objectionable pump noise.

    Source: Wikipedia

    It is doing its job if it runs all the time.

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