Pontiac Repair: compressor

Question
when i shut off engine on 97 bonnevill, something under air filter will not shut off. looks like a compressor of some kind

Answer
Hi rich:

depending on how this is equipped with emissions more then likely that is an AIR pump it should only run when the key car first starts up cold after sitting for a long enough period of time for the engine to cool down. if it keeps running then either the control for the compressor relay is stuck on either from a pinched harness or bad engine computer or the relay for the AIR pump is stuck on. it should not run when the engine is off. good luck :-)