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Thread: Astra 1.6 8v failed mot on emissions - catrastophically

  
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    Astra 1.6 8v failed mot on emissions - catrastophically

    Hi Guys,

    My car has just failed it's MOT with very high emissions figures.
    Does anyone have any idea what might be wrong, or where to best start?

    Results were:
    Fast idle test 1 - 3000 rpm
    CO = 4.08% (0.3 max allowed)
    HC = 432ppm (200 max allowed)
    Lambda = 0.904 (0.97-1.030 required)

    Fast idle test 2 - 3000rpm
    CO = 4.09% (0.3 max allowed!)
    HC = 486ppm (200 max allowed)
    Lambda = 0.895 (0.97-1.030 required)

    Natural Idle
    CO = 3.17 (0.50 max allowed)

    Any help appreciated,
    thanks guys..

    chugaboom

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    Hole in the exhaust?

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    guess.....cat knackered?

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    Quote Originally Posted by nry View Post
    Hole in the exhaust?
    would that not show while the tester is checking the exhaust tho?

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    Quote Originally Posted by munkie View Post
    would that not show while the tester is checking the exhaust tho?
    Yeah, probably, I'll go hide in the corner!

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    are you any good with tools? im guessing not? (dont mean to sound cheeky)

    take out the lambda sensors on the exhaust, one before the cat one after and clean them up with a wire brush or replace them. ask the mot man to just put it on the machine to see if it will pass, if not id go source another cat and manifold.
    1.6 8 valve, 5 door, soon to be a 5 studded let with crusty arches

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    Egr valve, put some redex in and take it for a good run!
    ARDEN BLUE GSI

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    Hi guys,

    It's been suggested to me that it's not the CAT... the MOT testing guy said the car is running very rich for some reason, and the exhaust was white and smelt rather oily.

    The EGR valve is almost certainly OK as it was replaced just over a month ago with a brand new DELPHI one, (and this did cure a fault where the ECU light was coming on, especially at higher revs.)

    Having said that, the ECU light came on during the MOT test today, for the first time since the EGR was changed...

    I think there must be a secondary fault..??

    Also the MOT tester said that only one lambda sensor was installed and that one appeared to be missing!

    HELP!!!

    chugaboom

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    Looking at those results it would suggest that your car is overfuelling or burning oil.

    Is it modified? I.e different air intake, or performance exhaust?

    1.6 8v.. would have thought that you would only have 1 lambda sensor as well.

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    the h/c level suggests that you have masses of unburnt fuel in the system and the lambda reading shows that you have one hell of a lazy lambda sensor that is barely switching. what you need to do to resolve this is to put a new lambda in and make sure it is a quality bosch one and you may also need to renew the crank sensor as these often contribute to small missfire issues that dump unburnt fuel in the system

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