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  1. #1
    Join Date
    Dec 2004
    Location
    Horley surrey
    Posts
    86

    Failed MOT on emissions

    Hi all can anyone recommend a garage near Gatwick that can sort out the emissions on my pilgrim sumo it has a 1980 rover 3.5 sd1 engine with a high lift cam and a edelbrock 1404 carb. It failed on the emissions on high HC. The co's were fine. It does struggle to pass every year, just scrapped through last year.

    Thanks
    Keith

  2. #2
    Join Date
    Mar 2006
    Location
    Oxfordshire
    Age
    69
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    1,742
    Keith,

    High HC levels are caused by unburnt fuel in the exhaust. In my experience this is usually due to an ignition fault/misfire, so check the usual things - low tension side wiring, coil, HT leads, plugs, etc.

    Good luck.
    Alan

    Ex CRC Thames Valley Regional Rep - please contact me if you're interested in taking on the role!
    UK Rep for European Cobra Club (eurocobra.boards.net)

    Dax 427 DeDion - now sold
    2003 E85 Z4 3.0i - the new toy!

  3. #3
    Join Date
    Apr 2014
    Location
    Stourport on Severn
    Age
    63
    Posts
    305
    What idle speed are you set to?
    There’s a big difference between HC readings on mine between 850 and 1000 rpm.
    Cheers
    Steve

    My missus asked me to build her a Cobra! – How good is that!

    AK Gen2 chassis arrived 12/2/15 IVA Passed 2/7/18 on road 29/7/18
    http://stevesakcobrabuild.blogspot.com

  4. #4
    Join Date
    Dec 2004
    Location
    Horley surrey
    Posts
    86
    Quote Originally Posted by conrod View Post
    Keith,

    High HC levels are caused by unburnt fuel in the exhaust. In my experience this is usually due to an ignition fault/misfire, so check the usual things - low tension side wiring, coil, HT leads, plugs, etc.

    Good luck.
    Hi Alan, thanks for the reply, I will check leads plugs etc, but when I drove it to the MOT today it seemed to run fine no missing or anything and I took the long way round to the garage to try and clear the cobwebs, maybe were it has had lack of use this year!

    Keith

  5. #5
    Join Date
    Dec 2004
    Location
    Horley surrey
    Posts
    86
    Quote Originally Posted by Peaches94 View Post
    What idle speed are you set to?
    There’s a big difference between HC readings on mine between 850 and 1000 rpm.
    Hi Steve,
    Idle speed is around 1000rpm

    Keith

  6. #6
    Join Date
    Apr 2014
    Location
    Stourport on Severn
    Age
    63
    Posts
    305
    On the idle speed, if the CO is ok, I believe they can run engine up to 2000 for the HC reading to achieve a pass.
    Cheers
    Steve

    My missus asked me to build her a Cobra! – How good is that!

    AK Gen2 chassis arrived 12/2/15 IVA Passed 2/7/18 on road 29/7/18
    http://stevesakcobrabuild.blogspot.com

  7. #7
    Join Date
    Dec 2004
    Location
    Horley surrey
    Posts
    86
    Quote Originally Posted by Peaches94 View Post
    On the idle speed, if the CO is ok, I believe they can run engine up to 2000 for the HC reading to achieve a pass.
    Cheers Steve, yes CO is fine don't know what rpm they checked it on.

    Keith

  8. #8
    Join Date
    May 2005
    Location
    Sheffield
    Posts
    1,049
    I thought ‘kit cars’ were visible smoke only. Is it more complicated than that?

    Nuf Said

  9. #9
    Join Date
    Feb 2011
    Location
    Northampton
    Age
    43
    Posts
    4,943
    Quote Originally Posted by nuf_said View Post
    I thought ‘kit cars’ were visible smoke only. Is it more complicated than that?
    The emissions test is as per the test in force at the time the engine was originally manufactured, so in other words - it's only 'visual smoke' if the engine fitted was made before 1975 (or 1987 if, for some reason, you fitted a rotary engine). 1975-1986 gets 4.5% CO & 1200ppm HC, 1986-1992 gets 3.5% CO & 1200ppm and after that it gets a bit more complicated with some years requiring a CAT test - there's a set of flowcharts in the IVA manual about it.
    My DeDion build diary..
    Hon Sec of the Digidash branch of the Unpopular Kit Car Design club

  10. #10
    Join Date
    May 2005
    Location
    Sheffield
    Posts
    1,049
    Thanks. Good stuff to know. I just recall my old MOT tester saying visual smoke only for all kit cars. When I said the same to the current tester he said yes, visual smoke only, but I noticed he still shoved the probe in the exhaust.
    nuf said

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