I have an 01 chevy blazer which I just replaced the air pump and was wondering if the air pump is suppose to run all the time with the engine on or if it is suppose to run only at certian engine temps?

 

im not sure how gm rigid this but the air pump is only suppost to run at certain times (mainly during the warm up period) and also when your cat is cold. if yours is running only at certains times and its not throwing a code then its just fine and u have nothing to worry about.

 

If your air pump goes again, like mine has (been replaced twice) make sure there is the plastic splash guard underneath and look into the air pump retrofit kit. The kit changes the tubes to different locations I was told, and prevents the pump from sucking up water, which it the number one killer of these pumps.