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TDI 170 Quattro performance problem - lags

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by lionyo, Aug 2, 2011.

  1. lionyo
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    lionyo Member

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    Hi,

    My TDI 170bhp Quattro laggs really bad before 3000rpm and even with my foot welded to the floor nothing happens until after 3000rpm when the turbo kicks in?

    Any ideas what could be causing the problem?

    Looking forward to your reply!
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  2. lionyo
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    lionyo Member

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    Anyone?
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  3. dubdemand
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    dubdemand VAG Addict

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    Don't know the cause but can confirm ours does this intermittently also, I think I read somewhere it can be caused by the EGR valve which costs in the region of 280 (non VAG part). It could also be the vanes in the turbo which I think can be cleaned up but can't confirm. If it isn't either of these then it could be new turbo time!?!

    It deffo isnt right though as when running right our has a nice and progressive power delivery...

    Have you had it on diagnostics to see if it's throwing and codes? Would be very pleased if you can post your findings as this is something I'm going to have to deal with sooner or later!
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  4. lionyo
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    lionyo Member

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    Thanks for your response mate!

    I did have the car checked on the computer and it throwed a fault code on the engine speed sensor and I cleared the fault code, after two days when I went back to the garage to find out exactly which sensor it was but when we plugged it back in to the computer the fault code didn't show. Maybe I should get the sensor changed anyway??

    I did think that the EGR valve could do with cleaning or replacing!

    Will look into the turbo vanes.
    Last edited: Aug 2, 2011
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  5. dubdemand
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    dubdemand VAG Addict

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    As I say I'm not too sure but have read people looking at this as a possible cause to the problem...

    I read about it here although you do have to register first to view the thread.

    Hope it sheds a bit more light on things for you?
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  6. lionyo
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    lionyo Member

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    Thanks for the heads up mate. It seems that the EGR could be the culprit and the best thing to do is to replace it with a new but I will try the cheaper option of cleaning and see if that cures the problem.

    Will report back with my findings. :icon_thumright:
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  7. dubdemand
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    dubdemand VAG Addict

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    Any news? I'm currently in Newquay and the car went into limp mode on the way in... not had the chance to get it back out on the road since we arrived yesterday but worried about thereturn trip now!
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  8. Mini-mad-matt
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    Mini-mad-matt Member

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    I have exactly the same problem as I have stated in other threads. Sometimes my car just feels gutless, and it keeps going into limp mode in very inconvenient places. Last time it happened was Friday as we were driving back from the Highlands to Manchester. As it happens, my sister was following us in her MINI which was also having problems, so I was driving that for a while whilst my wife drove the Audi. It was whilst I was following my wife that it happened, just as she was overtaking a truck on the motorway. It was lovely to see her try and cut back infront of the truck to get to the hard shoulder with our two very small children in the back!! (coincidentally, I was at that very moment telling my sister all about the problem.)
    It is going in on Tuesday to be looked at. It has been in before, and the EGR valve was very coked up. That was cleaned and then the car didn't do it for a while, and felt much quicker. The problem returned however. It always seems to be in similar conditions that it does it. Usually under very light acceleration on a slight incline. I've found that I have adapted my driving style a bit to compensate, by dropping down 2 gears into 4th for inclines on motorways, just to keep the revs higher and stop the car struggling.
    When my car was in Audi for its 4 new injectors the other week :), they read the logged fault code (which I already knew) and did an hours diagnostics on it, then came up with some stuff about the turbo was stiff. It wouldn't spin freely. They then quoted me £2500 to replace it. When I stopped laughing, I left the dealership.
    I'm still convinced it could be the EGR, and hopefully my very trusted independent garage will confirm this on Tuesday.
    Another thing I have noticed, is that the DPF seems to be regenning a lot more than normal. I put this down to the possibility ofmore **** going through the exhaust if the EGR valve is stuck open, or opening at the wrong time, therefore clogging the DPF up quicker, and bringing on the regen. I suppose this could also be the case with a failing turbo.
    Hope this helps.

    MMM
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  9. dubdemand
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    dubdemand VAG Addict

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    Thanks Matt, sorry about all the cross posting and the need for your multiple answers - I'm just trying to get as much coverage as possible and not wanting to miss any additional info!

    For reference my post for the 'other' forum:

    Fantastic info and much appreciated matey! We've just been for a blat up to watergate bay and it didn't miss a beat after an initial lack of power when we first set out. Have been discussing with the mrs and think that once we get back I'm going to look at replacing the EGR valve (assuming it gets us home).

    Seems to be a very common fault with these cars, almost as common as failed injectors... wonder if Audi will accept liability for this as well?

    Let us know how you get on in the next week fella and best of luck for your trip to Ireland :)
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