So here's the deal- I've looked through a few blogs to try and find the answer to this issue, but no one seems to know what this is.

There's a strange noise coming from underneath my air box of my 99 A4 2.8. I took out the box and found what looks to be some kind of fan or motor with hoses that run into the motor and to the top of the air box.

The fan/motor/ whatever this thing is started running continuously until it ran the battery dead.
My question is what is the noise and how do I stop it?

Please HELP!!

Below are pics of what I think the noise is coming from (almost 100% possitive)

http://i20.photobucket.com/albums/b2...zo/Audi008.jpg

http://i20.photobucket.com/albums/b2.../Audi010-1.jpg

http://i20.photobucket.com/albums/b2...zo/Audi006.jpg

[IMG]local://upfiles/18524/7E26BC0ECCBA4290A313B6C767D69535.jpg[/IMG]

[IMG]local://upfiles/18524/A1CE085F90124A65ADEED0A2997F62A3.jpg[/IMG]

[IMG]local://upfiles/18524/9002F0B798AD4BAEBEA5752FF09CC2C5.jpg[/IMG]

 

That is the secondary air pump. It should only run during cold start. Check the relay in the ecm box. It probably has stuck closed casuing it to run all the time. Otherwise the ecm is causing it to run constantly.

 

OK- Well, I pulled the pump out today...real fun!
Where is the ECM box? Is it the the main fuse box on the driver's side of the dash (inside)?

 

pics of the pump...

http://i20.photobucket.com/albums/b2...zo/Audi014.jpg

http://i20.photobucket.com/albums/b2...zo/Audi013.jpg

http://i20.photobucket.com/albums/b2...zo/Audi011.jpg

 

fault codes, if the secondary fan was on all the time the CEL would come on

 

OK- the fan/pump was constantly running for about a day before it killed my battery-
It won't stop running now which means the car will die within minutes of turning it off.
I never got a check engine light, so not sure what's going on.
The relay sounds like the most logical at this point...
Thoughts??

 

Can I just unplug the fan/pump?
Will the car still run?

OK- more helpful info... still researching-

Re: air pump cycles after car is turned off[/align]So far I found out that the above mentioned relay is inside the ECU weather resistant protective housing. If looking from the front of the car it should be on the left from the ECU metal casing.. [/align]

 

The car will still run without a functioning secondary air system. Just pull the relays out with the key on untill the pump stops running and you found the secondary air relay.

 

The fuse I pulled was in the weather proof box under the hood (in the battery copartment). There was a big orange 40 amp fuse and a grey relay right next to it. I pulled that relay. It reads: 373 on top in big numbers and PA66-GF25 on the side.
So I put everything back together (left the fuse out) and the car fires up and then dies instantly.

I can keep it running with my foot on the accelerator, but once I let it off, it dies out...
When the vehicle is running, it sputters and backfires....

 

Okay, so here's the latest.
I put everything back together and tried to drive the vehicle (just to see what it did)
I fired up the car and kept it running with my foot on the gas. I drove down the street and the vehicle would only go about 5 MPH- It was sputtering and dying out. It never stalled, but felt like it was going to. I could not accelerate over about 5mph.
When I pulled it back in the garage the vehicle had a strong, almost sulfur like smell...I mean STRONG! I also noticed whit smoke coming from the exhaust…