2009 A4 TSI

[John Larson]

On 6/2/2014 11:51 AM, Nick Lawrence wrote:
> Hello,
> I moved up about 2 decades in Audi technology and am getting a 2009 A4 
> Avant TSI.   I would like to know If there are knock sensors (most 
> likely), and how they function.
> Meaning if there is knock does the computer make changes and if it 
> continues to knock create a stored code?
> Is there ever any driver visible indicator that there is engine knock?
> Any insight will be appreciated.
> Nick   central Ohio
>
>
While I didn't work at a dealership in recent years, and I'm in a 
relatively small city and had only a few FSI cars pass through my shop, 
I wouldn't own one of them on a bet.  I'm guessing the TSI engines are 
essentially the same, although updated, design.  While (when I was in 
the business) I could offer only anecdotal commentary on this engine, I 
have found over the past few years that I wasn't the Lone Ranger on my 
negative opinion of the technology as applied by VAG.  Reading the help 
requests on iATN and following the trade magazines has revealed that 
decarbonizing of the valve stems, usually by media blasting, is pretty 
much required every 40-50K miles.  This means you have to remove the 
intake manifold (not an easy or quick job on the 4 cylinder turbos), 
blast the stems of the closed valves (and turn the engine to close the 
valves on successive cylinders).  You're looking at 5-10 hours labor + 
any gaskets, broken plastic hoses or connectors, whatever.  When 
independent shops are buying the equipment to do this job, you KNOW it's 
a profit center because it has to be done.

John