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  1. Siondc

    Siondc Learner!! Ming Blue S3 AMK

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    So my car failed it’s MOT on the emissions. I serviced it 2 days before and ragged it to the garage. It’s an AMK on 145,000. The results were:
    Fast Idle
    Engine speed:
    Limit 2500-3000 Actual 2820
    CO:
    Limit <0.3 Actual 5.1
    HC:
    Limit <200 Actual 188
    Lambda:
    Limit <0.97-1.03 Actual 0.87

    Second Fast Idle
    Engine speed:
    Limit 2500-3000 Actual 2540
    CO:
    Limit <0.3 Actual 4.3
    HC:
    Limit <200 Actual 257
    Lambda:
    Limit <0.97-1.03 Actual 0.89

    Natural Idle
    Engine speed 760
    CO:
    Limit <0.5 Actual 1.5

    I cleaned the pre cat lambda 2 days prior as this caused it to fail on the same things last year. Could it be that the lambda sensor needs replacing and if so what’s causing this problem to reoccur? Are there any other problems that could cause such high readings? Any help is greatly appreciated.
     
  2. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow... Staff Member Moderator Audi S3

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    Fault codes?

    <tuffty/>
     
    asad shabir likes this.
  3. Siondc

    Siondc Learner!! Ming Blue S3 AMK

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    Haven’t had it scanned yet, waiting to hear from a mobile guy to come and scan it.
     
  4. Stuart B

    Stuart B Well-Known Member

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    You own an audi s3 without the ability to scan for faults? Jesus.
     
    hydro s3 and S3AMJ like this.
  5. Siondc

    Siondc Learner!! Ming Blue S3 AMK

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    Hahahaha yea stu, I don’t know how I’ve survived for so long. What’s the best way to scan then? I know of vcds lite but that’s limited isn’t it? And I don’t want to pay £200 or whatever ridiculous amount it is for the the full thing.
     
  6. Stuart B

    Stuart B Well-Known Member

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    Vcdslite shows faults for free though. So for £5 you can save yourself time a money. I cleared about 20 faults from my TT yesterday. No EML no particular misbehaving.
     
  7. Siondc

    Siondc Learner!! Ming Blue S3 AMK

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    So I buy a cable off eBay, what site can I download it off then?
     
  8. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow... Staff Member Moderator Audi S3

    22,319
    4,447
    113
  9. Siondc

    Siondc Learner!! Ming Blue S3 AMK

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    9
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  10. Tj 0785

    Tj 0785 Well-Known Member VCDS Map User Bronze Supporter Audi S3

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    How much do you pay for your scans? £30-£40 roughly? Get car scanned 4/5 times(with an s3 could be anywhere from 1 or 5 years)
    Which is money you won’t get back but a cable and you will always be able to sell it for Close to £180
    Not so ridiculous when you think about it!
     
    Last edited: May 18, 2018 at 7:18 PM
    hydro s3 likes this.
  11. Retroman

    Retroman Audi A3 2010 Sportback 2.0 TDI 170 (CBBB engine)

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    For the MOT tests:-
    High CO is either a very rich mixture or ineffective cat. Your readings are way over the limits and so I would guess a Cat which isn't working at all.
    High HC is often an "incomplete combustion burn" so a poor spark is often the culprit e.g. old spark plugs or problem coil/lead
    Lambda problems in an MOT emissions test context does not relate to the lambda sensors but oxygen in the exhaust gases outside of permitted limits. Usually an exhaust system leak - exhausts gas pulses suck in air (from leaks) causing erroneous tailpipe emission readings.

    Faulty sensors normally trigger a warning light and error code e.g. they get old and react outside tolerance or go completely dead and cause an "implausible" signal.
     

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