Revs pausing when foot to the floor (with video)

[Chris128]

I mentioned this in this thread http://www.audi-sport.net/vb/showthread.php?t=78089 but apparently it doesnt look like my problem is related so just thought I would get some opinions on my particular problem.

A picture paints a thousand words so here's a video (worth a million words?) of my problem. I have my foot to the floor for the duration of both of the short clips in this video, but as you can see the revs seem to just pause at some points. It feels like I have just put my foot on the clutch for a couple of seconds when it happens (and no I do not have my foot right near the clutch!). It only does it if I floor it though, if I just gently accelerate it doesnt matter what rev range I am at it will just get there nice and smoothly. Both of these clips were taken in 5th or 6th gear, cant remember which.

http://www.youtube.com/watch?v=vmhCKZQeFQY

The second clip is the best example of what it does, when it stops just before 3K rpm in that clip. Its not normally as erratic as it was when I took that first clip.

Any ideas what could be causing this?

Thanks
Chris

 

[smudge_don]

Does the car accelerate smoothly whilst that happens?

 

[Chris128]

It seems to, I mean its certainly not noticeably jerky but I assume I must be loosing a bit of power when it does that? It sounds and feels exactly the same as if I had put my foot on the clutch, so I suppose its not really accelerating as it should be but then its not jerky or slowing down either if that makes sense

 

[smudge_don]

Hmmm, could be clutch slip, optimum torque is around 2700rpm so that would be near perfect according to that video

 

[Chris128]

It doesnt always happen at the same RPM though, so does that rule that out? In that first clip in the video (the very short one) you can see it is bouncing all over the place at around 2K RPM

 

[smudge_don]

Would be best to get someone with VAGCOM to check it out 1st to see if any error codes appear, or failing that, take it to Audi

 

[Chris128]

Yeah I will do if the dealer I bought it from cant fix it this weekend. Mentioned it to two guys at work and they both instantly said it sounds like the clutch slipping... it seems to be getting worse as well

 

[R-tech_Nick]

Hello,

It looks like it happens at the peak of the boost, the boost is cut back too much when its trying to come down to the requested level, a weak actuator, weak boost solinoid can make the cut back worse which give the pause in the rpm range, it could even be a boost pipe leaking which is stopping the linear pull.

Is your car remapped? If not see if there is a dealer software update for your ecu,
If you have the latest software on the ecu then you need to do a VCDS logging sessions on the spec & actual MAP and the boost control duty cylce, and MAF to see whats being asked for from the ecu and what the car is doing.

Nick

 

[Chris128]

Its not remapped no, but I'm pretty sure its the clutch because it slips a bit when I change gear as well now

 

[R-tech_Nick]

Its not remapped no, but I'm pretty sure its the clutch because it slips a bit when I change gear as well now

Can you get a video of the rpm vs speed? I dont think its a clutch fault as the rpm would creep up during the slip, it if i can see the speed i could give you a better answer.

Can you get your hands on vagcom to do a log?

Nick

 

[PregnantNproud]

something similiar happened to me.

I accelerated to 3k and the power stopped. I could not accelerate. even when i changed down and floored it.

Parked up for 10 mins and it was fine. SOMETHING IS WRONG lol

 

[R-tech_Nick]

something similiar happened to me.

I accelerated to 3k and the power stopped. I could not accelerate. even when i changed down and floored it.

Parked up for 10 mins and it was fine. SOMETHING IS WRONG lol

How many times has this happened?

Nick

 

[Chris128]

Well I took my car back to the dealers at the weekend... took it there for 10 AM on saturday morning, got the car back on Sunday afternoon and all they had done is break the radio... (they were supposed to be fitting a CD player at the same time, but iT looks like they just fitted it and didnt test it - when I got in the car it didnt work at all so now I dont even have a radio!). Their service manager is supposed to be ringing me today to sort something out.

Anyway, I showed them the video and they said it looks like the "air flow meter" whatever that means - does that sound likely? They said if it was the clutch slipping then it would do it all the time not just some of the time.