i was searching for a similar problem with my b6. i might have found the cause for it through the forum but i wanted to make sure or possibly confirm the problem. no lies , on cold start ups the engine sounds like a vaccum cleaner turning on , seriously. no turbo spool , no whistling , sounds like someone shoved a vaccum cleaner into my engine. Seems to originating from the air box/intake area. 2nd Air Pump?

btw im the guy who bought my a4 the first day and some dick rammed into it while i was shopping[:@] , damaged areas were the passenger side under carriage and passenger side fender , im guessing maybe some of the hosing might be damaged from the fender bender.

btw i figured out why my steering wheel wouldn't turn back from a certain position. the fender was pushed in and was rubbing againist the wheel , tearing up the treads in the process .

all the body work is complete , picking it up on monday. hopefully ill start posting something worthwhile after i get this behind me..lame

thanks

 

Yeah its either a bad SAP pump or a major line from the SAP pump is leaking. Check the lines to the SAP pump (under the air box) and if they are all hooked up correctly replace the pump.

 

thanks auditech , apperciate the help. will fix asap.

quick recap , will the SAP pump affect anything in my car? and is it okay to run it like it is.. probably going to fix sometime maybe next week or 2.

 

I wouldnt replace it unless youre going to sell the car and want it problem free. The pump isnt cheap, and only operates during the first couple mins on a cold start. It helps with cleaner emissions on a cold start. Its just an air pump that pumps fresh 02 into thecyl head. Most peoples pumps are noisy, but it doesnt mean its bad/dead, especially if you dont have any fault codes/CEL.
Mine is noisy like yours, but I dont have any fault codes,and I can think of better things to spend $300+ on. There is a DIY article on how to crack open your sap and replace the bearing inside/rebuild it. I have no idea where that link is.