krewbrew

I bought my A6 in October with 67K, and since then I've installed APR 93, a Samco TBB, 710Ns, a low temp thermoswitch and Borla mufflers. Found lots of tips and help on audiworld so far. I'm really enjoying my new ride, but, yesterday and today on cold start I heard the whining noise in the link below. It continues after engine shutdown.

The noise goes away entirely when the car warms up.

Any thoughts? I'm fearing the T word.



2003 A6 2.7T 6 Speed Black/Black
Sport Suspension
APR 93<ul><li><a href="http://www.youtube.com/watch?v=V2YOTmRXrhc">http://www.youtube.com/watch?v=V2YOTmRXrhc</a</li></ul>

GBW

but the youtube really sounds more like something rubbing. How long does is continue after engine shutdown...just a few seconds (seemed that way in the video)...maybe this link will help?

Maybe the air pump is just starting to fail...I'm going with this guess <ul><li><a href="https://forums.audiworld.com/a6/msgs/818357.phtml">..</a></li></ul>

Grapeking

sounds like(at least to my ears) a classic case of secondary air injection pump failure. Is it only when the temps are cold, and the car is cold? Does it stop after 60 seconds of engine warm-up?

If the answer to both these questions is yes, then check the SAI pump. It is located in the vicinity of the brake booster on the 2.7T. So, when the engine is cold, pop the hood, start the engine, and immediately stick your head in the engine compartment near the brake booster and try to localize the sound.

Audifan1

though. Weird.

Grapeking

reduce emissions levels while the cats are warming up (which is why we typically see these issues a lot more when weather turns cold).

krewbrew

Symptoms fit. Thanks, I'll scope that out and look to repair or replace.

A6Gary

It also operates on warm/hot start-up for less time to ensure that it is working.