Hello to all
I have a 2007 A6/C6 Avant with a 2.0TDI BRE Engine.
It has had a replacement EGR valve and throttle body (both VDO units) about 24 months ago. I've swapped out the MAF, and it has just been serviced. I was aware that the clutch was pretty worn, so was hoping that this being replaced would cure the issues, and a gen 3 piece clutch kit and LUK DMF have just been fitted. It made no difference....
In the past, I've had a "sticky turbo" where the veins have become clogged up with crud, but the local specialists have cleaned it out with Mr Muscle, and it's been a perfect treatment. I'm very aware of how the car is affected when the turbo is completely coked up, and when it's happened in the past, she couldn't even claw her way up a short (less than 1km), steep hill! (Ended up stranded and having to reverse back down and tow her home). It's worth adding, that the specialist cleaned out the turbo a month or two ago, but it made no difference this time sadly.... I'm confident that the veins are not presently clogged up, and I'm aware that she has a VNT turbo.
The symptoms I am getting are that it seems to have the majority of it's grunt and pull from 1750RPM to about 3000RPM. I still think it's a little short on the grunt, but she seems to pulls ok'ish.
However, she simply stops pulling after 3000RPM. She will go higher than 3000RPM, but will gather speed only very, very slowly indeed. To achieve actual acceleration, you need to change up a gear and get back down lower in the rev-range and she will start to pull again, back upto approx. 3000RPM, and then stop pulling.
I'm booked into a local specialist, but I'd like to do as much diagnosis as possible in advance. I had a bit of a chat with the guys that are going to look at it, and he's mostly thinking that there's most likely to be a problem with either the turbo itself, or possible the turbo pressure sensor. It's worth noting that there are no error codes whatsoever being shown on VCDS to help point me in the right direction!
Strangely (to me) he indicated that it was probably more likely to be the turbo as this didn't come online until about 2500RPM and beyond. Is this right? Whilst I'm no expert, I can hear (what I always thought) was the turbo whistling right down from 1500RPM on occasion, particularly if there is a load demand - for example a hill start on a steep hill, where a little more grunt is required than on the flat. I can still hear now, what I think/thought, is the turbo whistling away during acceleration.
Therefore, I'm unsure where to look. I would be extremely grateful if someone could help me, by showing me what sort of testing, or data logging/extraction I can gather with VCDS to help demonstrate what part of the system might be causing the issue?
Many thanks in advance for any replies.
I have a 2007 A6/C6 Avant with a 2.0TDI BRE Engine.
It has had a replacement EGR valve and throttle body (both VDO units) about 24 months ago. I've swapped out the MAF, and it has just been serviced. I was aware that the clutch was pretty worn, so was hoping that this being replaced would cure the issues, and a gen 3 piece clutch kit and LUK DMF have just been fitted. It made no difference....
The symptoms I am getting are that it seems to have the majority of it's grunt and pull from 1750RPM to about 3000RPM. I still think it's a little short on the grunt, but she seems to pulls ok'ish.
However, she simply stops pulling after 3000RPM. She will go higher than 3000RPM, but will gather speed only very, very slowly indeed. To achieve actual acceleration, you need to change up a gear and get back down lower in the rev-range and she will start to pull again, back upto approx. 3000RPM, and then stop pulling.
I'm booked into a local specialist, but I'd like to do as much diagnosis as possible in advance. I had a bit of a chat with the guys that are going to look at it, and he's mostly thinking that there's most likely to be a problem with either the turbo itself, or possible the turbo pressure sensor. It's worth noting that there are no error codes whatsoever being shown on VCDS to help point me in the right direction!
Therefore, I'm unsure where to look. I would be extremely grateful if someone could help me, by showing me what sort of testing, or data logging/extraction I can gather with VCDS to help demonstrate what part of the system might be causing the issue?
Many thanks in advance for any replies.
