I have an Audi a3 2.0 tdi 2004 automatic which is rough at idle when warm, almost like a misfire. What I checked until now is: Timing torsion value is at 0.5 , fuel consumption starts at 0.6l/h the drops down to 0 to 0.2l/h, injections values are are around 0 with injector number four being a bit worse than the rest but still around +-1. I took out the camshaft cover and bent the connectors to make sure I have a good connection to the injectors. Another thing I found by luck is that if restrict the airflow to the engine the engine idles fine. Another thing I checked is the fuel filter which I replaced and no, I didn't have any oil in the filter housing and I don't have any signs of diesel in the oil. no lose of cooling liquid. Yet another thing is that I think for some reason the turbo kicks in at idle as at soon as the rough idle starts I can hear a sound which is similar to the sound of the cooling fan working but that one is off. Everything I have at this point is saying that for some reason the ECU thinks the engine needs less fuel and less power, is like he thinks am decelerating.
And final no error codes except glow plugs error.
Please help!! :))
If it would be possible to cancel the question as it's not needed any more.
Not long after I posted the question the seals on injector number 1 gave up and I had to replace them so I replaced all of them on all 4 injectors and checked all the pipe connections and now it seems to be fine.
I have 3 theories to what the fault might have been, 1st leaky injector seals, 2nd vacuum leak and 3rd possibly some blockage in the common rail which cleared when the seals on the 1st injector failed.
Who knows I'm glad that it works, don't really know why but it works