Howling at startup?

**MarkuzLS1** · 05-30-2006, 12:23 PM

My car's got an intermittant problem. Sometimes, right when you start it up, it will make this loud howling noise. It doesn't always make it, but if it does, it's right when you start it up. When the engine revs up some it'll quit but usually comes back when it returns to idle. It'll carry on like this for a minute or two and then just stop. I've tried to tell where the noise is coming from with the hood popped, but can't isolate it. Anybody got any suggestions on figuring this out? Possibilities? Things to try? Any help appreciated.

**~redlinels1~** · 05-30-2006, 04:41 PM

Probably your A.I.R (air injection reaction) pump.

**2001NBMZ28** · 05-30-2006, 05:03 PM

Could be the pump - try pulling the AIR PUMP fuse under the hood to temporarily disable it - see if it stops making noise. It'll throw an SES light for P0412, but go off by itself after replacing the fuse and 3 cold starts. Pump is on the drivers side front, below the headlight area.

**MarkuzLS1** · 06-19-2006, 09:51 AM

I have determined that yes, it is the AIR pump. Where is this bastard? Is it not belt driven like it was in the old third-gens? Is it possible to just remove the pump? If I decide to replace it, how much is a new one? Somebody help me out.

**2001NBMZ28** · 06-19-2006, 01:25 PM

It's not belt driven, electrical. Posted some options in your other post. Lots of people do !AIR, maybe you can find a used one for cheap.

**~redlinels1~** · 06-19-2006, 10:19 PM

Its possible to take it off but it will throw an SES light (no power loss though). Just make sure to get a block off plate for the exhaust manifold. The pump is on the drivers side near the headlight area. You should be able to get to it from a little access panel in front of the tire.

**Frosty** · 06-24-2006, 07:35 AM

I kept it hooked up after I did my header swap.

I like the noise, I get a WTF look from people at times.

<---dork

**SeVeReDiStOrTiOn** · 06-24-2006, 06:21 PM

I get the howl now and then....anyone know if that's just from a worn pump or do they howl like that new also?

**Street Lethal** · 06-24-2006, 08:01 PM

Originally Posted by MarkuzLS1

I have determined that yes, it is the AIR pump. Where is this bastard?

You've determined that it is in fact the air pump w/out even knowing where to locate it?

It can honestly be many things. There are some instances when "spun" cam bearings will howl during cold start, that is, until it's primed with adequate oil to conceal it.

I would simply remove the serpentine belt, and try another cold start. If the sound is no longer prevalent, this will help pinpoint the area in which to look...

Originally Posted by SeVeReDiStOrTiOn

I get the howl now and then....anyone know if that's just from a worn pump or do they howl like that new also?

I thought they howled only when in heat.

**MarkuzLS1** · 06-26-2006, 05:01 AM

Originally Posted by Street Lethal

You've determined that it is in fact the air pump w/out even knowing where to locate it?

Yeah. I started the car and it was howling. I pulled the AIR Pump fuse and it quit. Put the fuse back in and it started back. Sounds like the AIR Pump to me.

**Street Lethal** · 06-26-2006, 05:13 AM

Originally Posted by MarkuzLS1

I pulled the AIR Pump fuse and it quit. Put the fuse back in and it started back.

You neglected to mention that...

Pepe LePew · 06-30-2006, 08:45 AM

My AIR pump did the same thing until I replaced the two check valves. They cost me about $10 each at Advanceautoparts.com and took about 20 minutes to install. I don't think I've heard the thing kick on since then...I know it's working, it's just a WHOLE lot quieter!