sabedra211

Hey my Lt1 camaro is making this wierd buzzing/whirring noise when you turn it on.. it goes away after 10 minutes. Is this normal??

Its a 94 z28 A4 I never noticed this noise before? it started doing this after i changed the opti.

Thanks

n2ceptor

Smog pump?????? Maybe

mrmint69

My sons V6 Camaro does this and it only does it cold. It has done this since we got the car and there are no issues from it that i am aware of. Its like the air going into the throttle body is making almost a sucking sound for the first 5 minutes or so. Maybe the emissions like stated ^ cause it.

Injuneer

Sounds like it could be the AIR pump, but it wouldn't typically run for 10 minutes at startup, only for 2 or 3 minutes. To check if it is the pump, simply pull the harness connector off the AIR pump (do not pull the fuse, that will set a code) and see if the noise goes aways.

sabedra211

Alright if i pull the connecter can i just leaveit off without anything bad happening???

Injuneer

You can unplug the AIR pump on the OBD-I cars (93-95) and as long as there is still a good fuse in the circuit, it will not set a code/SES light. It will not hurt the engine... the AIR pump runs for a couple minutes at startup to help the cat heat up faster.

sabedra211

Alright i unplugged my airpump and yes it is it. Y does it make this noise? Also i drove it to work and smoke came out of the hood and when i came home smoke also came out. This never happened before and my temps read normal? Does the air pump keep the cant converter cooler? I am running rich so should i have the airpump hooked up?
Thanks!

Injuneer

The AIR pump only runs for about 2 or 3 minutes at startup. It puts air in the exhaust, the oxygen combines with (burns) the rich cold-start mixture's unburned hydrocarbons, and the heat from that combustion helps the cats heat up. They have to reach ~600*F before they will work. Then the AIR pump shuts off and isn't used again.

The AIR pumps start to squeal because the exhaust gas starts to leak past the check valves at the manifolds, and the water in the exhaust condenses out in the cold pump, and the pump rusts up, causing it to be noisy when it does run.

You need to find out what was smoking under the hood. Did you look when you saw it coming out?

The AIR pump does not help keep the catalytic converter cool, and it will not affect how rich the engine runs, because the PCM stays in open loop (no feedback from the O2 sensors) until the AIR pump shuts off.

If you want to replace the pump, there should be a lot of people who can sell you one, since many remove the AIR system completely to clean up the plumbing under the hood.