Passed MOT with decat

Discussion in 'Engine, Gearbox, Exhaust and Air Intake' started by henderson, Apr 13, 2012.

  1. for all those running a decat i just thought i'd let you know my car passed its second MOT today with no problems on the emissions test,handy little tip though,use the passenger side exhaust,checked my emissions before the test using the passenger side exhaust,then during the test we used the drivers side tailpipe and the results where higher but still ok,thought it was good to know as if yr emissions are out this could be the difference between a pass and a fail

  2. Mattie


    Track 197 Daily 225 Lux
    Is that with a full decat or still have the mani cat?
  3. still have the manifold cat,just the secondary cat removed,for now anyway:smile:
  4. Foxspeed

    Foxspeed "the new red baron" Moderator


    didnt think it could pass an emissions test with it not there.....especially given the "new" rules that have come in to force :foxspeed:
  5. i thought that 2 hence the reason im still running standard zaust
  6. we checked the emissions first as soon as i arrived to make sure it was ok,no point starting the test if it was going to fail because as soon as the tester has log on he has to go through with the test and obviously charge me,using the drivers side tailpipe he did the emissions again in test time and they had risen slightly so he revved the car for a couple of minutes then did the test again at tick over using the passenger side tailpipe as we originally did and bobs yr uncle
  7. thats alright that is think im gonna look into a zaust now with the decat
  8. Foxspeed

    Foxspeed "the new red baron" Moderator

    did the test at "tick-over"........
  9. yeah,shouldn't he have? thats how all my cars have been done in the past,left ticking over with a probe up the exhaust
  10. Foxspeed

    Foxspeed "the new red baron" Moderator

    nope as there is a fast idel test and cat test - look up the emissions test for how it should be done....

    having said that he passed it so if anything happens its on thier doorstep as such...

    the emissions test isnt linked to the computerisation system so are both independent - so you could pass a faulty car - the emissions test paperwork has to be kept for 3month iirc

  11. Idle is how every car is tested here in N.Ireland. Over here the test centres are owned by the govt and thats what they are, test centres, they aren't garages that have test facilities. The only purpose they serve is for testing vechiles and there arent many of? Probably about 10 or so in the province. So if they all test at idle, then I would assume that must be the way to do it? Revving the engine can help to clear gases from the exhaust to lower emissions. The technician told me to do that when my skyline was running to high on emissions but it still failed! But if your car only fails on the emission test they will do the rest of the MOT test and if all is well, you only have to come back to do the emissions test not the full MOT. That's what they do over here anyway!
  12. Foxspeed

    Foxspeed "the new red baron" Moderator

    i must admit i am a bit rusty on mot regs having been out of work for awhile but the emissions test also depends on age/date of car reg and whether it has a cat which after i think aug 1992 it must have

    iirc you cannot measure cat emissions at idle speed...
  13. N0ddie

    N0ddie Platinum Member

    Mini JCW
    I thought regardless of emissions tests now, if your car had no cat it was a straight fail?
  14. Whenever my cars have been MOT'd, they usually perform a idle test then jam the peddle to a fast idle speed for a second test.
  15. could be me confusing matters here slightly sorry,the probe was left up the exhaust whilst he let it rev for several minutes so he may have been doing the fast ideal test at this point,wasn't paying to much attention tbh,i was just crossing my fingers and waiting for the thumbs up from him
  16. Foxspeed

    Foxspeed "the new red baron" Moderator

    ah that sounds more like it!

    still surprised it passed but if the machine said pass then fair enough not one to argue over the result - a pass is a pass :thumbup1:
  17. Yup mine also passed about a month or 2 ago with the de cat, also I've got the projector's with corning lights fitted with aftermarket HIDS which also passed, no self lever's or wiper jets.
  18. dozydinosaur

    dozydinosaur Gold Member

    Albi Blue Clio 197
    Reviving and oldy here I know... But im dubious about this...

    Has anyone else passed an MOT with just the pre-cat?

    I'm toying with buying a sports cat as I bought my 197 with a decat and I don't want the hassle of having to keep switching it over come MOT time.
  19. Beany

    Beany Platinum Member

    RB 200 cup
    Mine passed with just the precat

    @Benno presume yours is the same

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