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Thread: MOT failure questions

  1. #11
    Join Date
    Mar 2016
    Location
    Stogursey, Bridgwater
    Posts
    17
    According to the MOT tester he 'revved' the car excessively to try and get the readings to stay within the limits - unsuccessfully.

    Maybe putting in the cleaner and running the car for the 1 hour drive (25 miles) to the centre will help for the next test.
    Last edited by pewe; 24-01-2018 at 07:44 PM.

  2. #12
    Join Date
    Apr 2009
    Location
    Ecosse
    Posts
    3,512
    I had my 450 fail a few years back. When the CO was OK the Lambda was high, and when the Lambda was OK the CO was high. Tester reckoned the cat was fuct (it pretty much disintegrated during the test!) and a new one saw it sail through the retest. But, that retest was with a different (second one, downstream from cat) Lambda sensor but as it merely monitors the cat's efficacy, unlikely to have been the cause.

  3. #13
    Join Date
    Dec 2004
    Location
    Wells
    Posts
    1,541
    Twin exit exhaust? need to block the 'spare' exit off.

  4. #14
    Join Date
    Mar 2016
    Location
    Stogursey, Bridgwater
    Posts
    17
    Quote Originally Posted by lil.smartie View Post
    Twin exit exhaust? need to block the 'spare' exit off.
    Now you mention it there are 2 tailpipes.
    The car is a rare Highstyle (only 33 made apparently) and the previous owner was a young lad who was killed in a motorcyle accident, and his dad sold the car without any real knowledge about it, So I'm not sure if the twin exhaust was a 'custom' fit or if it is a genuine mod for the car.

    If this is the cause, I wonder why it passed last years MOT (done just after we bought it), and which is the 'spare exit' - not to mention if the MOT tester will allow a 'temporary' alteration for testing.

  5. #15
    Join Date
    Jan 2011
    Location
    uk
    Posts
    789
    Quote Originally Posted by pewe View Post
    Now you mention it there are 2 tailpipes.
    The car is a rare Highstyle (only 33 made apparently) and the previous owner was a young lad who was killed in a motorcyle accident, and his dad sold the car without any real knowledge about it, So I'm not sure if the twin exhaust was a 'custom' fit or if it is a genuine mod for the car.

    If this is the cause, I wonder why it passed last years MOT (done just after we bought it), and which is the 'spare exit' - not to mention if the MOT tester will allow a 'temporary' alteration for testing.
    Either I guess , probably down to their close proximity into the same chamber.
    You're so money supermarket and you don't even know it!

  6. #16
    Join Date
    Apr 2009
    Location
    Ecosse
    Posts
    3,512
    Quote Originally Posted by pewe View Post
    Now you mention it there are 2 tailpipes.
    The car is a rare Highstyle (only 33 made apparently) and the previous owner was a young lad who was killed in a motorcyle accident, and his dad sold the car without any real knowledge about it, So I'm not sure if the twin exhaust was a 'custom' fit or if it is a genuine mod for the car.
    451s had problems reading from Lambda sensors when aftermarket exhausts were fitted. There used to be a 'spacer' mod for the sensor.

    Quote Originally Posted by pewe View Post
    If this is the cause, I wonder why it passed last years MOT (done just after we bought it), and which is the 'spare exit' - not to mention if the MOT tester will allow a 'temporary' alteration for testing.
    MOT tester should know how to deal with twin outlets - the MOT tester's manual is available online if you want to check the procedure.

  7. #17
    Join Date
    Mar 2016
    Location
    Stogursey, Bridgwater
    Posts
    17
    Well - after running catclean through the system for 40 miles they still failed the car on an mot second test saying a new cat was needed.

    They quoted me £1000 to do the job!!!!!!
    I see the panels are simple enough to remove so I'll start there.

    With regard to the cat, would one of these be an acceptable replacement?
    What are the chances the Lambda sensor will need replacing?

    Where do I find the engine code?

  8. #18
    Join Date
    Apr 2009
    Location
    Ecosse
    Posts
    3,512
    Quote Originally Posted by pinger View Post
    Don't know the cost for a 451 but a complete (with cat) exhaust for a 450 can be had for £100 and will last at least a couple of years.
    Re Lambda sensor. Probably it is alright, but removing them can be a proper sod. But, you can cut it out of the old exhaust if necessary.

  9. #19
    Join Date
    Sep 2013
    Location
    West Midlands,England
    Posts
    56
    Quote Originally Posted by pewe View Post
    With regard to the cat, would one of these be an acceptable replacement?
    What are the chances the Lambda sensor will need replacing?
    If like my 2010 MHD you will find there are 2 lambda sensors in the standard exhaust system, one upstream in the short pipe from the manifold to the silencer and a downstream one in the big bit.

    I recently needed a new upstream sensor and after struggling, ended up removing the exhaust completely, which sounds like what you are contemplating. Removing the exhaust is not difficult but quite long winded.

    My last message on thread may be useful.
    http://www.smartz.co.uk/showthread.p...ght-EMCL/page3



    As this was the first time I had done this I followed the various forum guides........it starts with removing the side trims......honest.

    HTH

  10. #20
    Join Date
    Mar 2016
    Location
    Stogursey, Bridgwater
    Posts
    17
    Thanks guys.

    I just noticed I forgot to put the link in my last post.

    These are the cat/exhausts I was querying about suitability.

    https://www.onlineautomotive.co.uk/S...%20System.aspx

    Not sure why there are so many - different engines? where's the engine code/

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