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MOT Failure - Emissions

Discussion in 'A3/S3/Sportback (8P Chassis)' started by Fast,not furious, Jan 18, 2011.

  1. Fast,not furious
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    Fast,not furious Dealing with an OCD

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    :sos:

    My S3 failed the MOT yesterday on the emissions test at slow and fast idle: the CO (carbon monoxide0) is reading 0.20%

    It's been serviced recently too.

    Audi say they tried everything,but couldn't get the figure down.

    The car's Custom Code mapped,with sport CAT and C.A.I

    Any ideas??
    Last edited: Jan 18, 2011
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  2. Cyrix
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    Cyrix Member

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    If it's passed an MOT before I would probably be looking at the exhaust, either the CAT itself or an exhaust leak post CAT.
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  3. Fast,not furious
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    Fast,not furious Dealing with an OCD

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    It passed no prob last year,hoping it's not the CAT!
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  4. jungleman
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    jungleman Well-Known Member

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    iffy set of plugs maybe?
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  5. Fast,not furious
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    Fast,not furious Dealing with an OCD

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    Maybe,worth a try!
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  6. jungleman
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    jungleman Well-Known Member

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    be the cheapest thing to try, they been in the car long?
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  7. Fast,not furious
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    Fast,not furious Dealing with an OCD

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    About 25000 miles i guess?
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  8. jungleman
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    jungleman Well-Known Member

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    thats loads!!!!
    they must be knackered by now!!
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  9. Fast,not furious
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    Fast,not furious Dealing with an OCD

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    Is it? I thought they were good for 40k?...might be worth a shot then?
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  10. jungleman
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    jungleman Well-Known Member

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    maybe on a stock car, but yours is pretty heavily modified!! bet thats where your problem is!
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  11. Fast,not furious
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    Fast,not furious Dealing with an OCD

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    Just having a look at the readout:

    Fast idle test
    Speed Not checked
    CO 0.51%vol
    HC 146ppm
    Lambda 1.01

    2nd fast idle test
    Speed Not checked
    CO 0.47%vol
    HC 167ppm

    Natural Idle test
    CO 0.39%vol

    Summary results

    Oil temp 60
    Fast idle test Fail
    CO(0.20) fail
    HC (200) pass
    Lamb(0.97 - 1.03) pass

    2nd fast idle test
    CO(0.20) fail
    HC(200) pass
    Lamb(0.97 - 1.03) pass

    Idle speed Fail
    CO (0.30) Fail


    Oil temp looks low to me,surely a better result would be obtained wit a hot engine?
    __________
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  12. Khufu
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    Khufu Active Member

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    TBH, we find that high lambda reading needs new lambda/oxygen sensor & high CO2 needs cat (or two in your case!!). The issue could then be the sport cat and how the map is written for it :-(

    The oil temp isnt as crucial to that side of the test, more for the hydrocarbons. Its more important that the lambda sensor & cat are warmed up though usually a warm engine will mean a warm lambda & Cat.
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  13. Fast,not furious
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    Fast,not furious Dealing with an OCD

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    The exhaust's only about 2 years old :-(
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  14. Fast,not furious
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    Fast,not furious Dealing with an OCD

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    Sorted!!

    I ran some Wynns Gold fuel cleaner through her,gave it the beans so she was nice and hot and had it MOT'd at my local Citroen dealership,very helpful! One set of new plugs on standby,just in case though.
    Ok,so i couldn't take advantage of the free MOT at audi,but at least it passed!
    #14
  15. paddy
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    paddy Audi=No fault code, no idea

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    How much better were the readings ?

    My car failed the MOT 2 years ago at Audi's because of worn disc's....took it somewhere else and its been fine ever since. this year i asked them to check the disc's just in case and they said about 70% worn but fine for another year.
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  16. FranA3
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    FranA3 events moderator Regional Rep

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    i would be tempted to put a new set of plugs in there anyway as they have done alot of miles and are prob nackered by now
    #16

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