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Emissions Component

Condensation and Water Flow Back to Air Injection Pump

The smog pump on my GMC is bad. While attempting to replace it I found water (apparently due to condensation) inside the pump and suspect this is what caused it to fail. Water literally poured out of the pump when I removed it from the vehicle. I'm going to replace it but I don't want the same thing to happen again. What can I do?


The secondary air injection system pumps air into the engine's exhaust system when the engine is cold. This speeds up the process of heating up the catalytic converter; which is used to reduce emissions. The pump operates via switching valves which allow the air pump to pump air into the exhaust stream or atmosphere, as needed.

Condensation usually gets into the air injection pump due to a faulty air injection pump check valve. This is a large valve located in-between the air pump and exhaust manifold. Check the valve for damage. The valve is subjected to very high heat and in time will break, causing exhaust condensation to enter the smog pump. Once the condensation liquefies it will freeze up the pump. It is always recommended to replace the smog pump check valve whenever replacing the air injection pump, unless of course the check valve was recently replaced.


posted by SmogTips Support

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