Huge shout out to the OP for the information ( and the rest of the Audi-sport community )
My newly acquired Allroad BiTdi started to develop 2 subtle issues;
1) as the the engine was warming up, at the point of approaching’ normal ‘ running 90°C temp, a misfire or uneven rpm experienced at low throttle demand ( eg maintaining 30mph ) also resulting in the gearbox swopping between gears unnecessarily.
2) lack of refinement as mentioned in the other posts , sounding like an old clattery diesel on light acceleration- this went away on higher throttle demands.
As off on holiday today, thought I’d take a quick look after finding this thread yesterday. Image is before cleaning obviously
Considering the relatively low mileage of the car (34K) I was surprised by the dramatic amount of deposits in the swirl flap/inlet runner housing, the short inlet pipe with the EGR return and into the inlet manifold. Due to restricted time available, it was a clean of the swirl flap assembly ( leaving in the butterfly) , accessible bit of the inlet manifold and the delivery inlet.
Outcome: all issues gone, large increase in refinement, low down lag improved. Probably the most rewarding hour I’ve spent on a car in a long while !
Finally for those who’ve found a challenge to get to some of the more awkward position screws, this little set from tool company Bahco has help me on some many occasions:
Bahco 2058/S26 1/4" Drive Ratchet and Socket Set 26 Pcs The Bahco 2058/S26 is a compact, pocket sized socket bit set with 26 pieces. Contains 18 different types of bits and 5 small sockets ranging from 6 - 13mm. The set is supplied in a plastic carry case with sponged lining that is labelled...
www.powertoolworld.co.uk
Others styles of this set are available, Bosch do a similar iirc , but can only comment on how robust the Bahco set is for such a small tool. Obviously it’s not gonna undo a seized M10 bolt, but those awkward to get to jobs, it’s been great.
will update if I decide to take the inlet manifold off for a proper clean and see how much crap there is around the inlet valves etc……