Hi all. Yesterday my 2005 A4 Quattro 1.8T started making a very loud whining noise from the engine compartment. It sounds like a tea kettle on a stove. My fuel pump filter has been clogged before and it sounds very similar to that, except that the fuel pump is in the rear of the vehicle. The noice only occurs when I am coasting, idling, or at a full stop. Never when I am accelerating. I can't quite pinpoint the sound but it's near the drive belt. Any ideas?? Could it be the drive belt?

Seemingly unrelated but at the same time...my check engine light came on the very next day. When I open the hood (underneath the tea kettle noise) I can hear and feel air coming somewhere as well. I have read throughout these forums that Autozone will either read the engine codes or rent an engine code reader. Is this a regional thing? Every Autozone I have called out here in Northern California doesn't do either.

 

You just show up and ask them to read your codes, they do it for free, I used to do it all the time just because it was free.

You might have a vacuum or air leak, I don't know much about the turbo engine. Also if you have a "humming" noise, I wouldn't discard a bearing as being the issue.

 

Sounds like a secondary air injection (SAI) pump hose has come loose. Take a look on your passengers side - take the belly pan off - and you will see a black pump with some corrugated hoses attached to it. Many times the hose will come off the pump or break somewhere down the line. Do a search for SAI and you will probably pull up an image so you know what it looks like.

 

I went to Autozone. They told me that they don't read codes but they'd gladly sell me a $200 piece of hardware to do it myself. They also said they don't rent anything. I don't get it. Maybe they are just jerking me around or something.

Anyways, I ended up taking the car to a local Audi specialist (2Bennett.com). They pulled these codes:

16684
16687
17763
17769
17772
17519
17544
16555
16891

They told me that all of these codes are associated with air leaks. They state that they have confirmed a major leak at the breather system baffle at the back of the head.

They recommend that I replace the breather hose system with associated restrictors and valves between block and valve cover as a set. They provided me with an estimate of $500 for parts and labor.

Does this seem reasonable? It didn't seem like a lot to me, but I'm no expert. Is there a website that I can pull up the code definitions?

 

2Bennett is your local specialist? They're good, I was going to take my car there but I ended up going to Santa Clara instead. I don't know about the price but seems reasonable to me too, I'm sure someone here is going to tell you that you can do it yourself for much less...

 

Prolly only $150 or so less.. those hoses, restrictors and valves aren't that cheap to begin with.

 

Any places online that I can cross-reference those codes??

 

http://www.bentleypublishers.com/tec....dtc.table.htm


16555 P0171 Fuel Trim,Bank1 System too Lean

16684 P0300 Random/Multiple Cylinder Misfire Detected

16687 P0303 Cyl.3 Misfire Detected

16891 P0507 Idle Control System Higher than Expected

17519 P1111 O2 Control (Bank 1) System too lean

17544 P1136 Long Term Fuel Trim Add.Fuel,Bank1 System too Lean

17763 P1355 Cyl. 1, ignition circuit Open Circuit

17769 P1361 Cyl. 3, ignition circuit Open Circuit

17772 P1364 Cyl. 4 ignition circuit Open Circuit



Sounds like more than just a vacuum leak.

 

That's what I'm worried about. Why would they tell me that all of these codes are associated with air leaks when clearly they are not??

 

I googled each one of them, it could be all related, but you already changed your coilpacks and spark plugs haven't you?