HI All - just reading this old thread after a search for cam timing (torsion) adjustment after cam belt replacement due to poor fuel economy.
For info I had the injector recall (170 tdi 2.0, BRD, Audi A4) and after had running issues and oil in the fuel. Reading many similar threads, including where a technician posts, his statement was on this engine, oil and fuel mixing was always leaking injector seals/poorly seated injectors. One case was the holes in the head had become ovaled. The only other possible cause of this is the tandem pump, but the tech said this engine (later tandem pump) has never had TP issues. Its always bad sealing/seating after the injector recall.
Main dealer did not really want to know, checked diagnostics and said no leaks and to speak to Audi UK if I still had an issue. So I did. Audi UK initially said 'poor workmanship' I would have to go back to the dealer, not AUK issue - and they have not had any other issues reported after the injector recall, which a quick Google will reveal is complete BS - clearly LOTS of people have this exact issue. So I lost it a bit (politely!) and they assigned someone from customer complaints to it. They got the dealer to (very reluctantly) replace the injector seals (not injectors, just the 2 'o' rings on each. It is crucial they are fitted correct way round.
Unfortunately there is NO way to identify poor sealing/seating so you have to remove the injectors and re do it - and take extreme care and make sure the holes/seals are spotlessly clean. The slightest contamination can cause the seal to leak a little.
Anyway, seems immediately better after it was done. Early days, but believe it has cured the issue, keeping everything crossed but so far so good.
Key info is the ONLY way oil and fuel mix in this engine type is by passing the injector seals (due to damage, contamination or poor seating) or the tandem pump - and its apparently never this! - but a cheap easy to replace part, so you could try replacing this to eliminate it).
So now, I just need to sort why after the cam-belt replacement the fuel economy dropped 20% - and it cant be the belt off by a tooth as I would have a wrecked engine by now, so the consensus is the 3 degrees +/- adjustment on the Torsion value, which also effects starting and idle (but NOT fuel/oil mixing!). Mine starts lovely, even in the cold it starts instantly, half a turn! But fuel econ on a long motorway trip is down from 50-52mpg avg to 43-46 mpg. Not sure whether I need to retard or advance to get this back to where it was pre cam belt change. As the 'Independent' VW group specialist in Chandlers ford Southampton did not even put the bumper back right, then I wont have them touch it again.
