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TDI 170 running rough, anything to be concerned about?

Discussion in 'A3/S3/Sportback (8P Chassis)' started by audigex, Feb 3, 2013.

  1. audigex

    audigex Active Member

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    Hey guys

    Just done a 50 minutes/30 mile trip home, half in the city (ie stop-start) and then half on fairly twisty A-roads. Didn't notice anything wrong, although I wasn't paying particular attention. Stopped for a subway 5 miles from home, and noticed afterward that the car was sounding a little agricultural. She seems to pull fine, but the sound is just a little more dieselly than I've been used to.

    Temps were fine, but when I stopped and went to the boot I smelled a very faint burning smell - this could be unrelated, as a lot of people near me have coal/wood burning fires. The fan was also running, which seemed strange as it's about 1.5 degrees here and the journey, while not cruising, was hardly strenuous. I doubt I hit 4k rpm all the way home, and the last 5 miles involved two 0-40s and mostly 6th gear at 1200rpm.

    She's 10 months/13k miles old, so it may just be that she's lost that new car perfection... am I being paranoid, or is it worth getting her checked out?

    Cheers
     
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  3. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat
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    Relax, test again tomorrow, if it proves to be a problem then get it looked at, could be dpf.
     
  4. The Governor

    The Governor Active Member

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    Definitely wasn't an active regen? My car gets smelly and runs slightly rougher when doing those...
     
  5. chinnyhill10

    chinnyhill10 Member

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    Running rough and a burning smell usually just means the DPF has just been on a regen cycle. Nothing to worry about.
     
  6. audigex

    audigex Active Member

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    I thought the DPF regen only happened when at motorway cruising speeds? So wouldn't it have been far more likely to occur a week ago when I did 130 miles at 70mph? Thanks though guys, I'll keep an eye on it.
     
  7. chinnyhill10

    chinnyhill10 Member

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    No, not at all. This seems to be a myth. Mine seems to pick hills to do it when the engine is at 2500rpm or more. Speed has nothing to do with it, what seems to be more important is load. Which makes sense as the engine will be hotter.

    I can do a couple of hundred mile run but the next day the car will still pick the hill out of town at 40mph to do the regen. Did it on Friday in fact.
     
  8. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat
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    Its more than likely based on the percentage the dpf is currently at, which denotes the time to regen, cant imagine its based on load, could be wrong, but that logic seems little weird if so.
     
  9. chinnyhill10

    chinnyhill10 Member

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    I'm not saying it happens up that hill every time. I assume the ECU looks at the soot loading, and when the engine conditions are right decides to go for it. Going up a steep hill will make the engine run hotter thus providing ideal conditions for the ECU to trigger a regen.
     
  10. The Governor

    The Governor Active Member

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    I do mostly long runs, but you can guarantee that mine does a regen when I do the short school run. It's a really unsophisticated system...
     
  11. davesimmo

    davesimmo Member

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    Sorry to hijack, how do you know when the car does a regen and how long does it take? Not noticed mine doing it before :wacko:
     
  12. The Governor

    The Governor Active Member

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    I notice that the revs are unusually high, the engine seems to be a bit laboured and ususally the radiator fan is running. Plus you get a chemically/burning smell when you step outside.

    It's a bit rubbish tbh, I wish it could give you an option when to run it, like I say mine always goes when I'm doing a short run so I often interrupt it.
     
  13. chinnyhill10

    chinnyhill10 Member

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    If you are on the power when it initiates a regen you will actually feel the car cough. The car will also start running slightly rough + if you step outside while the exhaust is still cooling down you will get a burning smell + hear the occasional creak from what I assume is the heat shielding cooling down.

    If you want to be sure, put your hand near the exhaust. If its red hot you have either just interrupted a regen or it has just finished.

    However as one person put it, "drive more, worry less". I've interrupted regens and no problems as yet. People assume the process is intelligent, it really isn't. It just looks at the parameters and goes for it when they are met.

    The thing is you'll only ever notice it if you were on the beans when it started or you interrupt a cycle. Most of the time it runs seamlessly.

    A good example of that was I was caught up in traffic on the M3 after a smooth run. Sitting in the traffic I suddenly detected a slight smell of burning. The car had obviously been in a regen mode when it had come to a halt. Would have had no idea if I hadn't had to stop! At motorway cruising speed its pretty undetectable.
     
  14. davesimmo

    davesimmo Member

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    OH I see. From a couple of pointers I had read in your posts, I have felt the regen after all. Yeah I am not worried about it. keep driving as normal. If it breaks then its time to worry lol. :ermm:
     
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  15. audigex

    audigex Active Member

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    The DPF theory seems to work, as she was as smooth as ever today to/from work. It wasn't actually particularly noticeable, I just happened to turn the radio down while maneuvering (a bit of a habit, it really pisses my missus off) and hadn't turned it back up when I noticed the car sounded a little rough. Power etc still seemed fine although I wasn't driving spiritedly.

    It does seem strange timing, but I was under the impression it was more intelligent than it is so that makes more sense now. How often would a regen normally occur? I've probably missed some because I'm normally on the motorway with my music quite up, on cruise control... so I won't notice it over the drum&bass. My car is also fairly new-ish, so I suppose it probably didn't happen for a few miles from new?

    Anyway, cheers chaps - as always, you make me panic a little less about my wallet. Dave, unfortunately I rely on my car too much to be able to worry about it only when it breaks. Time is money etc. I'll relax a little when the girlfriend gets a car... but as she's eyeing up a Citroen, I'd still rather leave my reliability in the hands of a well maintained A3 rather than any sort of Francemobile.
     
  16. The Governor

    The Governor Active Member

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    Habits that wind our women up while driving #17 :eyebrows:

    Hard to tell how often, as I understand it it's based on how blocked the filter is, so it hits a percentage then does it, I keep a note of any regns I notice against mileage, I'm not sure why, another thing I do that winds my missus up :w00t: I would prefer it to warn youas the percentage gets near so you can make a decision to go on a long run or not, as I said above mine neartly always triggers when I have to interrupt it.

    Nothing like having a second car as a de-stress tool, my wifes Fusion is my "knockabout" car.
     
  17. davesimmo

    davesimmo Member

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    Yeah I would worry too, but I am ok because I would just use the missus VW Polo, so still got reliability, used to be be a FROG machine fan until she met me, now she is converted to GERMAN machines! :friends:
    I have another that winds the missus up, I keep all my fuel receipts, when asked why and I tell her its so I can work out the running cost at the end of the year, I just get..... WHY??
    Now that is a question I can't answer, think its just a bloke thing. They don't understand! lol
     
  18. The Governor

    The Governor Active Member

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    I've got a few, I think there's a new thread in there somewhere :D
     
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  19. The Governor

    The Governor Active Member

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    Case in point re active regen.

    I did my usual 33 mile commute today, I've not used the car for short journeys in about 6 weeks, so each time it's been started it's done at least 30 miles.

    I had to nip out at lunchtime to a shop about a mile away, and of course the regen starts as I park. So, not wanting to interrupt it I had to go for a ten minute drive.

    The system seems geared towards interruption, if there was a message on the DIS prompting that a regen was due or something like "DPF 60%, run regen now?" I could have kicked it off during my commute.

    As it stands it just waits til the DPF is at a certain figure and runs regardless of the situation.

    It's a very agricultural system and wastes fuel, if you interrupt it then the burned fuel has been totally wasted. Rubbish system if you ask me.

    How much for a DPF delete again? :tocktock:
     
  20. davesimmo

    davesimmo Member

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    A DPF delete seems to be the way forward. I am going to have it done this year. However, I heard that with new MOT regs coming in to force soon. This would result in an instant failure. How true is this? Is it true that it will only effect cars registered from 2009 onwards. :-(
     

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