MOT failure on emissions - S3

JD09

JD09

I'm not modding, I'm improving
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Hi guys,

My car failed it's MOT this morning. First one in its 12 years on this planet :(

Emissions are at 3+ when apparently they should be 0.3 or below.

I have noticed a drop in performance especially when cold and a drop in fuel efficiency recently... Last time it was a faulty MAF... So presume that'd be my first port of call with a few logs?

I have an s2000 filter and b5 tip but both have been through previous emissions tests without failing.
 
JD09 said:
I don't think so no. I've seen a few posts from searching about ragging the car first. Does it really do the trick then?



Sadly I don't have any MOT friends!
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Cats need to be hot working properly, the idea is to rag the car on the way to clear things out before the MOT.
 
Broken Byzan said:
hydrocarbons or c02?
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CO - and I got the figures wrong; limit is 0.3 and mine ran 1.34.

9ea616ebadaa405b51bacd967a331a63.jpg


jojo said:
Cats need to be hot working properly, the idea is to rag the car on the way to clear things out before the MOT.
Click to expand...

Ah ok. So, if my car has been doing short journeys pretty much all year that could be the issue? Is there any way to test it myself at home? Last thing I want to do is spend another £45 for it to fail again...
 
So both then. I'd look at faulty pcv system and or lambda more likely. Also add an oil change to help drop hc. Any codes? Or logs since economy went south?
 
Broken Byzan said:
So both then. I'd look at faulty pcv system and or lambda more likely. Also add an oil change to help drop hc. Any codes? Or logs since economy went south?
Click to expand...

No codes with dash command. Going out later to do some logs with the laptop and vcds.

Oil changed not that long ago. Did have a rattling cat shield which kwik fit removed rather forcefully... Worried that's done damage to the lambda...!
 
Sorry to hear your MOT woes JD, I thought I'd look up my emission sheet as mine is due early Nov.
Mine from last year seems slightly different layout to yours.
Fast Idle Limits are 0.20% and mine read 0.04%
Natural Idle Limits are 0.30% and mine read 0.02%
No 2nd idle test on my sheet, suppose they all very slightly depending on equipment used. I also have a rattly cat heat shield which I hope won't cause issues with MOT as I plan to get 3"inch downpipe & sports cat fitted after MOT this year (interesting to see how figures change next year)
 
Just out of interest I checked my previous years (2012) emission test which was from a different tester using SUN equipment & although passed comfortably was a slightly higher reading on CO & Lambda. Last years (2013) was using Boston Garage equipment & all reading slightly lower. Hmmmm can these test equipments vary then & should I go back to the one that had the lower reading just in case :idea:
 
jojo said:
It's free retest up here, at least it is for me anyways! ;)
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Yeah I've misread it. It says either no fee if left there or minimal fee if removed from the tester. I should have asked but it'll be going back on Saturday anyway.
 
jojo said:
It's free retest up here, at least it is for me anyways! ;)
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Just an update - sailed through this morning with no issues. Blasted it about over the last five days in the evening, 30 min blast before the MOT, all good.

Thanks to all in the thread. I've still only been able to use dash command and iOBD11 iPhone apps for scanning fault codes as I live with a "hidy-er" as a mate put it (she doesn't tidy, she hides things!) so can't find my vcds lead...
 
JD09 said:
Just an update - sailed through this morning with no issues. Blasted it about over the last five days in the evening, 30 min blast before the MOT, all good.

Thanks to all in the thread. I've still only been able to use dash command and iOBD11 iPhone apps for scanning fault codes as I live with a "hidy-er" as a mate put it (she doesn't tidy, she hides things!) so can't find my vcds lead...
Click to expand...

Interestingly, my cousin called me the other day to tell me his 57 plate Golf GT failed the MOT on emmisions, I asked him if his car was hot when they tested it? He said no, it was a mile down the road, and the first test of the day, so I told him to take it for a blast down a dual carriageway in 3rd gear at 5k+ revs for at least a mile. He took it back in the afternoon for a free retest on just the emmissions, and it passed easily!
 
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