MOT fail on emissions

1. swaterman1408 L-plater Joined: Apr 2010 Posts: 49 Saxo vts

   #1 6th December 2010, 22:18

   as above, any ideas on what sensor it could be. It passed on everything except the co levels.
2. Matt-T Established Member Joined: Oct 2010 Rednal Posts: 1943 Vauxhall Vectra VW Golf Mk4 Honda Prelude

   #2 6th December 2010, 22:22

   Lambda sensor, take it out give it a clean with some carb cleaner, if that dont work replace it ( i would replace it anyway lol)
   
   If problem still arises, maybe need a new cat
3. swaterman1408 L-plater Joined: Apr 2010 Posts: 49 Saxo vts

   #3 6th December 2010, 22:27

   Lambda sensor reading was fine, I was thinking more o2 sensor or somthing.
4. Alexywhite Infrequent Poster Joined: Jul 2009 Oxford Posts: 222 Citroen Saxo VTR MK2 DC2 Integra Type R EP3 Civi

   #4 6th December 2010, 22:30

   Quote:

   Originally Posted by swaterman1408 Lambda sensor reading was fine, I was thinking more o2 sensor or somthing.

   A 'Lambda' sensor is an O2 sensor!
5. RustySkull Saxperience Post Whore Joined: Oct 2009 Basildon And Corringham, Essex Posts: 5179 MK1 Focus RS, Discovery TD5, Renault Trafic 2.0

   #5 6th December 2010, 22:35

   Quote:

   Originally Posted by Alexywhite A 'Lambda' sensor is an O2 sensor!

   Yup!
6. Tontsy Saxperience Addict Joined: Oct 2008 Plymouth, Fiddling - under a two poster ramp Posts: 14064 Audi

   #6 6th December 2010, 22:41

   o2/ lambda same thing mate.
   
   was it during fast idle or idle it failed?
   what were the readings? as "failing the emissions" doesnt really narrow it down!
   
   if he was a shit tester, the engine / cat may not have been hot enough to work.
   have you had it on a good run recently?
   replace the sensors. generally rear sensor is enough, depending on what he readings were.
   
   also... not taking the piss, but you sure your not de-catted?
7. swaterman1408 L-plater Joined: Apr 2010 Posts: 49 Saxo vts

   #7 6th December 2010, 22:52

   The readings were:
   Fast idle
   co max 0.300%= 0.614% fail
   Hc max200 ppm= 51 pass
   Lambd max 0.970-1.030= 1.026 pass
   Natural idle test
   co max 0.500%= ).405% pass
   And it still has the cat.
8. user_15516 Saxperience Post Whore Joined: Apr 2007 Posts: 6640 Integra DC5R & VTS

   #8 6th December 2010, 23:04

   Exhaust totally air tight?
   
   How old is the CAT? If it's a cheap one from a motor factors, they only really last an MOT or two.
9. user_31412 Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653

   #9 7th December 2010, 03:44

   Get some of this splashed in : Cataclean Catalytic Converter Cleaner - ive always wondered if it works or not
10. burgerfeet Infrequent Poster Joined: Oct 2010 Bridgend Posts: 231 VTS 2002 - well the Mrs does

    #10 7th December 2010, 07:01

    Quote:

    Originally Posted by swaterman1408 The readings were: Fast idle co max 0.300%= 0.614% fail Hc max200 ppm= 51 pass Lambd max 0.970-1.030= 1.026 pass Natural idle test co max 0.500%= ).405% pass And it still has the cat.

    ='s inefficient cat, not lambda as the result for this is 1.026 which is good and shows it is working.
11. LVC Frequent Poster Joined: Aug 2010 Le Mans, France Posts: 976 VTS, Hawkeye WRX, Def90 & Freelander HSE (ex-VTR)

    #11 30th December 2010, 16:31

    Just had the same problem with the new VTS at the French MOT.
    
    Lambda 1.027 - pass
    CO on decleration : 0.76% -fail (has to be below 0.30%)
    CO on acceleration : 0.74% - fail (has to be below 0.30%)
    
    It has a CAT fitted but the box after the CAT looks like it's been split and re-welded. I presume the CAT is the first box going from the engine towards the rear?
    
    Any ideas please - new CAT, clean CAT (if so how), etc. etc. ????
12. ashleyoneill Frequent Poster Joined: Oct 2005 Chippenham, Wiltshire Posts: 796 Mk2 Wicked Red VTS

    #12 30th December 2010, 16:46

    I had my car MOT'd recently and it failed on CO.
    
    It failed the first time with my CAT and then failed again with my friends CAT. Took it to a guy that's good at diagnosing problems and he said it was 100% the CAT at fault.
    
    Had the CAT changed for a brand new one and it went through the MOT at 0.097% CO
13. LVC Frequent Poster Joined: Aug 2010 Le Mans, France Posts: 976 VTS, Hawkeye WRX, Def90 & Freelander HSE (ex-VTR)

    #13 30th December 2010, 20:59

    Where's a good place to get a new cheap CAT for the VTS ?
14. ashleyoneill Frequent Poster Joined: Oct 2005 Chippenham, Wiltshire Posts: 796 Mk2 Wicked Red VTS

    #14 30th December 2010, 21:05

    Your local independent tyre and exhaust supplier.
    
    Personally i would take it to a top mechanic that diagnoses emissions faults all the time and spend £50 to find out what the problem is.
    
    No point changing the CAT just cos i said so as it may not be that. The CAT may be fine and just masking another fault that's causing the high emissions.
    
    Better to do that than spend money left right and centre without being sure.
15. ashleyoneill Frequent Poster Joined: Oct 2005 Chippenham, Wiltshire Posts: 796 Mk2 Wicked Red VTS

    #15 30th December 2010, 21:05

    Quote:

    Originally Posted by LVC Where's a good place to get a new cheap CAT for the VTS ?

    I paid £109 at a local independent exhaust specialist.
16. user_15516 Saxperience Post Whore Joined: Apr 2007 Posts: 6640 Integra DC5R & VTS

    #16 30th December 2010, 21:08

    Most motor factors will be able to get you a new CAT for £60 or so, but don't expect it last more than an MOT or two.
    
    A genuine PSA/ good quality CAT will last a lot longer.
17. LVC Frequent Poster Joined: Aug 2010 Le Mans, France Posts: 976 VTS, Hawkeye WRX, Def90 & Freelander HSE (ex-VTR)

    #17 30th December 2010, 21:16

    The previous owner tells me that "he bought a new one 4 years ago when he bought the car as the emission were high" - I think that was about 40k miles ago so it looks like it could be the culprit.
    
    I've got a de-Cat pipe to put on once the MOT has been passed so don't really want to spend much at all as it'll only be on it for the MOT run and back every two years (MOT's are every 2 years in France).
    
    Annoying thing is that it has a UK MOT valid for one year from the end of August - maybe the tester was more lenient.
18. LVC Frequent Poster Joined: Aug 2010 Le Mans, France Posts: 976 VTS, Hawkeye WRX, Def90 & Freelander HSE (ex-VTR)

    #18 31st December 2010, 20:52

    Since the MOT failure yesterday I've taken more notice of the exhaust fumes and have noted 2 things: 1. They smell "heavy" and 2. the exhaust "smokes" quite a bit even when the car is hot and has been running for a good few miles.
    
    I'm wondering whether the problem is more of a "tuning" set up rather than just the CAT - I think it might be worth taking to a tuning specialist with a rolling road to get a more in depth diagnostic before shelling out on a new CAT.
    
    The car pulls really well - much more oomph than the VTR - there's no dodgy/bad noises and no obvious oil leaks etc. so I think it might be worth investing in a decent tune up/diagnostic.
    
    Any thoughts/advice please ???
19. user_15516 Saxperience Post Whore Joined: Apr 2007 Posts: 6640 Integra DC5R & VTS

    #19 1st January 2011, 21:13

    How is the car on fuel?
    
    If the economy isn't too great, it's possibly overfueling - I'd be checking out the coolant temperature sensor, pre-CAT lambda sensor etc.