I have a 2000 Silverado pickup 5.3 engine. There is a whine/hiss/hum noise coming from the secondary air injection area and it almost seems to be the air pump itself. The noise only happens when I first start the vehicle and goes away after 30 seconds to a minute. Does anyone have any suggestion on how to remedy the problem or troubleshoot it.
Thanks in advance.

 

The pump will normallyrun on start up for up to a max around 3 minutes.Length depends on a variety of different things.Ifyou do not haveaccess to ascan tool you will need to isolate noise quickly! The pump shouldwhine when running. Check for obvious itemsbefore taking it in- Loose hoses/broken plastic clamps, missing retaining hardware, plugged inlet, etc.