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MOT Failure On High CO
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Old 19 Nov 2009, 01:35 AM   #1 (permalink)
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MOT Failure On High CO

Hiya all,

My 55 plate (Hawkeye) 2.5l STI Type Uk just failed its mot on emmissions, the CO averages between 0.9% and 1.1% when max allowed is 0.3%, it has the standard exhaust with cats in place, I have an elmscan 5 compact with the scanxl std software and there are no faults standing at all, could it be that either o2 sensors are starting to fail or possibly 1 of the cats failing? I have checked all over for leaks in intake system and cant find anything, I also tried a petrol additive but that didnt work. Checking diagnostics it seems the sensors are working ok although not sure what correct readings are meant to be. below is the mot test results :-

Fast Idle Test:-

Engine Speed 2458 rpm
CO Level 1.06%
HC Level 47ppm
Lambda 0.99


Second Fast Idle Test:-

Engine Speed 2531 rpm
CO Level 0.99%
HC Level 27ppm
Lambda 0.99

Idle Test :-

Engine Speed 781 rpm
CO Level 0.82%

Thanks for any advice given
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Old 19 Nov 2009, 07:52 PM   #2 (permalink)
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Re: MOT Failure On High CO

How many miles has the car done?
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Old 19 Nov 2009, 08:03 PM   #3 (permalink)
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Re: MOT Failure On High CO

It has done 40,235miles , its booked to go into a performance garage for a diagnostics a week on monday if i dont locate problem before then
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Old 28 Dec 2009, 12:04 AM   #4 (permalink)
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Re: MOT Failure On High CO

HELP! I also have an mot emmisions failure but on a 94 classic wrx. I knew it would fail due to lack of cats, but my question to everyone is with it being an import there are no rear fog lights as standard nor any dipped headlights as standard. The rear fog light is no problem i can sort this, but the dipped headlights bit is there anyway around this? The rear fog light may be aviodable also, previous mots seem ok, and cant see where there may have been an external one applied previously. Anyone recommend an mot garage local to Worcester where these may not fail? cheers Gareth
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Old 28 Dec 2009, 12:34 AM   #5 (permalink)
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Re: MOT Failure On High CO

[QUOTE=GarethDalley;356357]nor any dipped headlights as standard. The rear fog light is no problem i can sort this, but the dipped headlights bit is there anyway around this? /QUOTE]

what do you mean by "dipped headlights".

All cars in Japan come with the same headlight config as UK cars; side lights, dip and main beam. They have to have dipped lights to pass the Japanese MOT.

You have pulled the headlight stalk back to switch off the main beam I take it? f they are not turning off you likely have a wiring issue.
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Old 28 Dec 2009, 08:29 AM   #6 (permalink)
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Re: MOT Failure On High CO

Have a look see if the fog light has been turned round, Ive seen a few that mount them upside down(so inside the bumper) between mot`s,
As said unless you have had the headlights replaced they came with dipped/main beam on all cars made since about 1969, a few countries have daylight running lights but I dont know of any that dont have dipped/main beam,
What failed on the mot ?
Sometimes you can whip the panel filter out to help emissions or has it failed having no cat in ?
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Old 28 Dec 2009, 04:30 PM   #7 (permalink)
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Re: MOT Failure On High CO

you dont have to have external fog light you can switch the drivers side reversing light into a fog ,you need a red bulb and obviously a switch mounted on the dash the switch must illuminate on turning on this is requirement but it is perfect legal way round .without having a rear fog hanging down .My mate used an led third brake light on his skyline and positioned it on the bottom of the bumper it looks very cool and passed mot fine.the dipped beam question is a problem because yuor car should definately have this import or not no manufacturer would produce a car without, sounds stupid but check your bulbs have not been changed for off road spec ones i have seen cars fitted with these cheap bulbs looks good to you but not oncoming traffic .
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Old 29 Dec 2009, 07:35 AM   #8 (permalink)
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Re: MOT Failure On High CO

thanks for advice guys, the mot literally said no front side lights? i advised the test centre that there wasnt a cat on the car at all i knew it wouldnt pass emissions test due to this. I will check the side "dipped" lights im sure that they are there. thanks again Gareth
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Old 29 Dec 2009, 09:11 AM   #9 (permalink)
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Re: MOT Failure On High CO

I should check with the garage re sidelights fella I seem to remember someone else post on here that their car had failed for no sidelights and it was cause the numpty mot station didn't know where the switch was
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Old 29 Dec 2009, 12:23 PM   #10 (permalink)
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Re: MOT Failure On High CO

yes dan they didnt know where it was on my classic lol
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Old 29 Dec 2009, 06:00 PM   #11 (permalink)
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Re: MOT Failure On High CO

I couldn't remember who had posted about the side lights and couldn't find the thread. after submitting my post I suddenly had that " I think I might just have made that up"feeling
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Old 29 Dec 2009, 10:52 PM   #12 (permalink)
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Re: MOT Failure On High CO

Change the oil and filter that will help your emissions
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Old 30 Dec 2009, 11:46 PM   #13 (permalink)
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Re: MOT Failure On High CO

oil and filter changed about 200 miles ago, having checked it out i think either the two front bulbs are duff or their not wired in on side lights, the backs both work. nice easy one hopfully, not sure why they didnt state "no bulbs on dipped fronts"? thanks for help.
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Old 31 Dec 2009, 07:04 AM   #14 (permalink)
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Re: MOT Failure On High CO

Quote:
Originally Posted by Skullstah View Post
Hiya all,

My 55 plate (Hawkeye) 2.5l STI Type Uk just failed its mot on emmissions, the CO averages between 0.9% and 1.1% when max allowed is 0.3%, it has the standard exhaust with cats in place, I have an elmscan 5 compact with the scanxl std software and there are no faults standing at all, could it be that either o2 sensors are starting to fail or possibly 1 of the cats failing? I have checked all over for leaks in intake system and cant find anything, I also tried a petrol additive but that didnt work. Checking diagnostics it seems the sensors are working ok although not sure what correct readings are meant to be. below is the mot test results :-

Fast Idle Test:-

Engine Speed 2458 rpm
CO Level 1.06%
HC Level 47ppm
Lambda 0.99


Second Fast Idle Test:-

Engine Speed 2531 rpm
CO Level 0.99%
HC Level 27ppm
Lambda 0.99

Idle Test :-

Engine Speed 781 rpm
CO Level 0.82%

Thanks for any advice given
Make sure the car is very very hot before putting it on the gas test... best to take the car for a blast down the motorway at speed and keep the engine running until the gas test is due... rev the engine before test to burn off excess fuel etc then fingers crossed...

Good luck...
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Old 31 Dec 2009, 07:47 AM   #15 (permalink)
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Re: MOT Failure On High CO

Be careful with some MOT centres / garages.

They will fail you first time on emissions to get some work. An easy way to make a false reading on the emissions os to NOT put the sensor on the exhaust properly.
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