Strange noise when engine started

**Varanus762x39** · 05-08-2009, 04:12 PM

I have a 1999 Trans Am (non WS6). I purchased this vehicle used several years ago. There is a strange whiring noise noise from the somewhere in the front of the vehicle when it is first started. After the car idles for a few minutes the noise usually goes makes a high pitched whine and goes away. Nobody I've taken the car too seems to know what it is. I've driven other 4th gen f-bodys (a Z28 camaro and formula firebird) and none of them made this noise. Anyone have any idea what it could be?

**pajeff02** · 05-08-2009, 05:57 PM

If your year is equipped with an air pump, that is probably what it is. The air pump is located in front of the driver side tire. It activates on start up and blows filtered air into the exhaust in order to get the cats up sooner. After running for a bit, it shuts down. Access is through the splash shield under the front.

**Varanus762x39** · 05-08-2009, 06:16 PM

Maybe that is what it is. Does it normally make that much noise? One of the other f-body's was a 1999 (the formula) and the other was a 1998 (Z28 camaro). Neither of them made the noise. Is the air pump standard on the trans am and not the camaro or formula?

**dklowrider** · 05-08-2009, 06:25 PM

Originally Posted by Chief762x39

Maybe that is what it is. Does it normally make that much noise? One of the other f-body's was a 1999 (the formula) and the other was a 1998 (Z28 camaro). Neither of them made the noise. Is the air pump standard on the trans am and not the camaro or formula?

emissions stuff should only vary by year not by model.

**jmatt07** · 05-08-2009, 07:31 PM

i have a 98 ss and it was making the same noise. It turned out it was the air pump. just get under there and disconnect it.

**99RTA** · 05-09-2009, 04:26 AM

Try timing the noise...if its the air pump it will run for exactly 2 mins.

**Cutlass** · 05-09-2009, 05:42 AM

Originally Posted by Chief762x39

Maybe that is what it is. Does it normally make that much noise? One of the other f-body's was a 1999 (the formula) and the other was a 1998 (Z28 camaro). Neither of them made the noise. Is the air pump standard on the trans am and not the camaro or formula?

No its not supposed to be really noisey. Its probablly on its way out.