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Acceleration juddery and rough idle

Discussion in 'A3/S3/Sportback (8P Chassis)' started by absolutelymike, Sep 8, 2013.

  1. absolutelymike
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    absolutelymike New Member

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    Hi all,

    Hope you had a great weekend.

    I recently bought an A3 2.0 TDI 140 BKD (2005) and it is mostly great fun to drive, however, I am having teething problems with it. It has 125k on the clock and had a new cam belt about 4 years ago (80k). I have read lots of threads/discussions on here already so I know that this is widely talked about.



    The problem: It seems to idle very rough and judders (like the odd misfire) around the 2500 - 3000 rpm if accelerating moderately, which means that it's jerky. If I accelerate through it and change gear above it, I don't feel it so often. It seems happen more on up hill driving, but I have discounted the clutch because of the rough idle and the fact that it does it going down hill too.


    I have taken it to my local garage and they ran the VAG diagnostics and can't find any faults to do with this - although injector 3 is running slightly less than the others, I have been told that this is within tolarance:


    [FONT=verdana, sans-serif]12:34:43 Group 013: Idle Stabilization (Injection Quantity Deviation)
    [FONT=verdana, sans-serif] 0.05 mg/str Injection Quantity Deviation Cyl. 1[/FONT]
    [FONT=verdana, sans-serif] 0.05 mg/str Injection Quantity Deviation Cyl. 2[/FONT]
    [FONT=verdana, sans-serif] -0.54 mg/str Injection Quantity Deviation Cyl. 3[/FONT]
    [FONT=verdana, sans-serif] 0.42 mg/str Injection Quantity Deviation Cyl. 4[/FONT]
    [FONT=verdana, sans-serif]
    [/FONT]
    [/FONT]
    I have been advised to drive a little more sportily because these engines don't appreciate pottering around - I used to drive a VW Transporter before so I wasn't used to high revs!!!


    Anyway, I have changed my driving style but it still doesn't seem right to me. I have read all sorts of articles on line to do with:

    • injectors
    • injector seating
    • injector wiring loom
    • cam timing - torsion settings
    • EGR throttle body
    • air leak
    • fuel filter
    • fuel pump
    • DPF blockage
    • etc

    and really don't have an answer. I tried some injector cleaner from Halfords which didn't make any difference.I intend to try a better one just to see what happens.

    I have had the IMF changed as that was faulty - jammed open - but nothing has changed regarding the juddering.


    I'm hoping this something that somebody's going to say 'Ah, I know what that is...' or 'I've seen this before and its the...'


    I would be grateful of any help advice.
    #1
  2. smurfworth
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    smurfworth Well-Known Member

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    i have and had both these issues, cured the judder on acceleration by changing the fuel filter which helped the judder on idle.

    still have the judder on idle though which is royally annoying, turning the car off sorts that out though
    #2
  3. AudiMafia
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    AudiMafia Member

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    Have you changed fuel filter and oil filter recently? and also cyl nr 3 is throwing minus that can make the car judder at certain speed is doing at mine atm
    #3
  4. J8TT X
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    J8TT X Member

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    My rough idle was sorted with a new flywheel and engine mount (it was cracked)
    #4
  5. absolutelymike
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    absolutelymike New Member

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    thanks for the replies guys, much appreciated. I'm gonna start with the cheapest option first by changing the fuel filter. I'll report back if it makes a difference.
    #5
  6. Dan_Mol
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    Dan_Mol Member

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    When idling, remove the oil cap check if suction behind it?!
    #6
  7. absolutelymike
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    absolutelymike New Member

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    thanks Dan_Mol, but what does that indicate?
    #7
  8. Dan_Mol
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    Dan_Mol Member

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    Faulty PCV

    Replaced mine last Friday, gasket and valve £52 from TPS.

    If you check oil cap and pressure behind I'll send part numbers over, took about 20-30mins to change.
    #8
  9. Dan_Mol
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    Dan_Mol Member

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    Possibly ignore that didn't the important part of being a diesel.
    #9
  10. sportbacksport
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    sportbacksport Member

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    Try replacing the temperature sensor! I had a similar problem on my mk5 golf and fixed it.
    #10
  11. tdi-man
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    tdi-man Well-Known Member

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    the - reading is not a problem unless in reaches -3 or +3

    judder on idle on mine was fixed by turning the idle down to 800 - 810


    #11
  12. absolutelymike
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    absolutelymike New Member

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    Reporting back that the fuel filter change was quick and easy. Unfortunately it did not cure the acceleration judders!
    Oil filter was changed at the last service and the idle is at 800 btw chaps.

    May have to book this in with a tuning expert for a second opinion.
    #12
  13. tdi-man
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    tdi-man Well-Known Member

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    have u looked at idle speed in vag com
    #13
  14. absolutelymike
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    absolutelymike New Member

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    yes tdi_man, it reads 819.
    #14
  15. tdi-man
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    tdi-man Well-Known Member

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    820 - 830 I get a shake

    800 - 810 I don't


    #15
  16. smurfworth
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    smurfworth Well-Known Member

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    how'd you change it?
    #16
  17. absolutelymike
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    absolutelymike New Member

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    Oh, and I've also noticed that it only does it when the engine is hot. If I use the rev range 2500 - 3000 when it's cold I don't get the judders. Weird, you'd expect it to be the other way round.
    #17
  18. absolutelymike
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    absolutelymike New Member

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    I'm thinking it could be a temp sensor. Could this cause it to start missing when hot?
    #18
  19. Matt_Storm
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    Matt_Storm Member

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    Might be worth checking the fuel pipes from the filter havent been swapped a garage put mine on the wrong way round once and my car did the same as you described.
    #19
  20. absolutelymike
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    absolutelymike New Member

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    thanks Matt_Storm, I'll mention that when it gets checked over on Thursday as I wouldn't know if it looked wrong or not!

    The temp light came on today because the coolant was way to low. I've done 1000 miles since I last checked it and I was surprised to see the light come on. It may well not have had enough antifreeze/G12 in it or could it be another sign that something's not right?
    #20
  21. AudiMafia
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    AudiMafia Member

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    i changed that and it made no difference
    #21
  22. absolutelymike
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    absolutelymike New Member

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    It turns out that it could be injector 1. So the garage are getting an injector so that they can swap them about ... I will keep this thread updated as I have read a lot of stories similar to mine.

    Oh and the radiator leaks, that explains the coolant loss.
    #22
  23. tdi-man
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    tdi-man Well-Known Member

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    0.05 mg/str Injection Quantity Deviation Cyl. 1
    0.05 mg/str Injection Quantity Deviation Cyl. 2
    -0.54 mg/str Injection Quantity Deviation Cyl. 3
    0.42 mg/str Injection Quantity Deviation Cyl. 4

    shows is very good for injectors
    #23
  24. chris.vincent3
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    chris.vincent3 Member

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    I had this sort of problem on mine once I fitted an ITG Maxogen air filter, removed it and put original back on and seems fine. Have you got an aftermarket air filter on it?
    #24
  25. absolutelymike
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    absolutelymike New Member

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    Those injector readings were taken when cold, they read differently when hot. It's still at the garage so I can't check the air filter although I will mention it to them. Thanks for the input guys.
    #25
  26. absolutelymike
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    absolutelymike New Member

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    So, just for anyone that was reading this and wanted to know the outcome. It is now two days after injector 1 was replaced and the car is driving without judders! On idle it is mostly better and I can live it, far better than it was.
    #26
  27. tdi-man
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    tdi-man Well-Known Member

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    did u keep the old 1



    #27
  28. absolutelymike
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    absolutelymike New Member

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    nope, didn't think to ask :/
    #28
  29. Miked6405
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    Miked6405 New Member

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    I had the same problem and I took the injectors out and give them a clean with wire wool fitted them and the problem disappeared this was over a year ago, I tried all sorts of injector cleaner and none of them worked
    #29

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