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Emission Control warning Light, erratic idle speed = my car doesn't like motorways!

mancdan Oct 16, 2012

  1. mancdan

    mancdan Active Member

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    I keep getting a problem whenever my car has been on a Motorway/dual carriageway run.

    I recently went from Manchester to Glasgow for the weekend and upon returning back to Manchester the Emission Control Warning light came on when I exited the Motorway after approx 4 hours driving.
    The light stayed on for 2 days and then went off. This was 2 weeks ago.

    The light has now come back on and been on for approx 48 hours and I haven't done any long driving runs.

    The other problem I have is erratic idle speed again every time I go on a motorway run, even if its just for a couple of miles.
    When I exit the motorway and come to a stop, the idle speed varies between 1000 and as much as 1400 rpm sometimes, it sounds like my car is revving its tits off!
    The only way I can bring it down is to gently let the clutch out a bit, but as soon as I depress the clutch again the idle speed begins to creep up. Its so annoying that I now hate it every time I use a Motorway or similar type of road.

    I have had the Coil pack recall done plus recent Cambelt & water pump change, but the erratic idle speed was present before these were done anyway.
    Anyone have any ideas what the problems could be? Could they be linked?

    Thanks, Dan.
     
  2. mancdan

    mancdan Active Member

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    Emission Control Light now gone off again!

    Could the ECU be temperamental/faulty and does anyone know approx cost to replace the ECU?
     
  3. solaris

    solaris Member

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    Could be the PCV valve, a scan would confirm this..more info here
     
  4. mancdan

    mancdan Active Member

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    Thanks Solaris, this sounds just like my problem as I have noticed MPG has gone worse too.
    Can you remember the price of the PCV Valve and is that the Audi Part Number (part number 06F129101N)?

    Cheers, Dan.
     
  5. olethalb

    olethalb Active Member

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    mine does the same ocasionally, just fitted BSH PCV fix plate but still does it. seems to be an issue with a split pipe to my carbon cannister.

    As Solaris says though PCV is first port of call
     
  6. mancdan

    mancdan Active Member

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    Any idea on approx cost of PCV Valve and Gasket?
     
  7. olethalb

    olethalb Active Member

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    i bought a plate that gets rid of the PCV part completely, turns out my PCV was fine anyway (recently replaced) by precvious owner.

    sorry can't say how much a new PCV is
     
  8. mancdan

    mancdan Active Member

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    How much was the plate you bought then olethalb?
     
  9. olethalb

    olethalb Active Member

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  10. mancdan

    mancdan Active Member

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    OK, PCV and gasket successfully changed last Friday. Took me about 15 mins once I got the correct tools!
    Part Numbers & prices were as follows: PCV at £37 = 06F 129 101N and Gasket at £18.40 = 06F 103 483E

    BUT, still got the erratic idle issues and the Emission Control Warning light has come on again :wtf:

    Is it time to get someone with VCDS to plug it in??
     
  11. hades-

    hades- Well-Known Member VCDS Map User

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    i cant belive ppl still change parts when hey havent had a scan for codes
    its a waste of time and money
    it could be a split pipe or even the MAF
    unplug the maf see how it runs.
     
  12. mancdan

    mancdan Active Member

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    I did think that bez but read somewhere that changing the PCV valve after 50k miles was a good idea anyway, but lesson learned!
    Where abouts is the MAF?
    (By the way, was it you I came to in Sheffield to clear my airbag light when I changed the wiring under the seat?)
     
  13. hades-

    hades- Well-Known Member VCDS Map User

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    iv done a few infact loads
    so yeah could have been
    across from the pub an carwash ?
     
  14. mancdan

    mancdan Active Member

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    I think so, on the main road with tram lines?
    Rough idea as to where the MAF is so I can unplug??
     
  15. hades-

    hades- Well-Known Member VCDS Map User

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    yeah thats me
    the maf is on the left as your looking under the bonnet on the pipe going to the airbox
    put a pic up ill point it out.
     
  16. mancdan

    mancdan Active Member

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    Here you go Bez, hope picture is close enough.

    A4 Engine bay.jpg
     
  17. hades-

    hades- Well-Known Member VCDS Map User

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    remove the big airpipe
    and you will se eit under there
     
  18. mancdan

    mancdan Active Member

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    Should the MAF just unclip and pull out or do I need to remove those security torx screws?
     
  19. mancdan

    mancdan Active Member

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    Unplugged what I thought was the MAF (part no. 06F 906 461A) and ESP light has come on!
    Have I unplugged wrong part?
     
  20. hades-

    hades- Well-Known Member VCDS Map User

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    the MAF may send a light on
    there is 2 security screws holding it to the tube
    when u get a new maf its already in that tube
    to clean it u need to remove them i have a use 1 with around 1k miles on it
    take a pic with thebig air pipe off ill point it out
     
  21. mancdan

    mancdan Active Member

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    I didn't need to remove air pipe to unplug the MAF so will need to remove it and then take a pic for you.
    Let me know how much you want for your used one too.
    Cheers.
     
  22. hades-

    hades- Well-Known Member VCDS Map User

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    (it was the MAF you unplugged)
    how did it drive when you unplugged it
     
    Highlander1969 likes this.
  23. mancdan

    mancdan Active Member

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    Haven't drove it yet but am about to leave work so will know in the next few mins and report back later!
     
  24. ANDYTQ

    ANDYTQ Well-Known Member

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    Mine idles too fast when cold so changed pcv anyway its done 88,000 so probably past its best,i would like to give the valves a clean next and change fuel pump follower at the same time.
     
  25. mancdan

    mancdan Active Member

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    Well, unplugging MAF didn't alter the erratic idle as it appeared again this morning whilst in traffic and I had only driven on A/B roads, max speed 35mph and done approx 6 miles. Also the Emission Control warning light came on again.
    I have now plugged the MAF back in again and ESP light has gone out but ECW light has stayed on.

    This is a video of the erratic idle whilst at some traffic lights this morning. You can see that I revved it a little at 8 seconds to see if it would go back to normal and it didn't.
    I also let the clutch out a bit at 22 & 46 seconds to get the idle down, but as soon as I depress the clutch back in, the idle speed goes back up again.

    Its driving me fckin mad now and I'm thinking it really needs to go on VCDS.

     
    Last edited: Oct 26, 2012
  26. hades-

    hades- Well-Known Member VCDS Map User

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    if your around my way again ill scan it you
    see if the problem is stored
     
  27. mancdan

    mancdan Active Member

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    Cheers Bez, I'm never usually around Sheffield but would make a special trip there just to get it scanned as its really bugging me!
    When is a good time/day for you?
     
  28. hades-

    hades- Well-Known Member VCDS Map User

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    sunday after 5pm
    or day next week after 7pm
     
  29. mancdan

    mancdan Active Member

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    Cheers mate, I will let you know.
     
  30. mancdan

    mancdan Active Member

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    This issue has now been fixed by Rick & Spencer at Unicorn Motor Developments in Stockport.

    It turned out to be the N80 Valve and so far the idle speed is perfect and car runs a lot better too.
    Cost of new part approx £25 plus an hours labour to fit.

    I would like to give a big shout out to both these guys as they are very thorough and have a great wealth of knowledge.
    I would have no hesitation in recommending their services.

    Now to save some pennies for one of Rick's customer remaps!
     
    mister.c. likes this.

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