GTti
Member +
I usually use Arden Park in Old Wolverton.
Failed MOT coz my CO is too low!!!!!!!!!
- Thread starter Paul_JJ
- Start date
I usually use Arden Park in Old Wolverton.
xx YICK xx
Member +
Hi Paul, Go in tommorow and ask them for an appeal form (it was a vt17 when i was testing) That might scare them into re-doing it (too many appeals and the ministry go in)...Good luck
btw never ever take your car to a fast fit centre they work on bonus ie mot fails
btw never ever take your car to a fast fit centre they work on bonus ie mot fails
The basic emissions test every car must pass, It cannot fail on the co or hc being low as this is the idear the only measurable value that can be low is the lambda.
Here is a link to the actual guide line for testing the car this is the procedure that must be used by the mot tester!
http://www.transportoffice.gov.uk/c...nualsandguides/mottestingmanualsandguides.htm
Here is a link to the actual guide line for testing the car this is the procedure that must be used by the mot tester!
http://www.transportoffice.gov.uk/c...nualsandguides/mottestingmanualsandguides.htm
Thx for your support guys!
I think he was trying to sell me the service and then re-test the emissions - that's what the manager said!!! I said I've serviced it on Saturday (2 days before the MOT), for which he replied you would have to book a re-test again!
I will ask for an appeal form, that was the cheapest MOT centre I found locally, I know my car is in minted condition - the emissions would be the only thing it would fail as I can't test it myself!
Jay how come did you get such emissions with a DECAT?????
I think he was trying to sell me the service and then re-test the emissions - that's what the manager said!!! I said I've serviced it on Saturday (2 days before the MOT), for which he replied you would have to book a re-test again!
I will ask for an appeal form, that was the cheapest MOT centre I found locally, I know my car is in minted condition - the emissions would be the only thing it would fail as I can't test it myself!
Jay how come did you get such emissions with a DECAT?????
e.g. A 1995 car first used in Africa has a letter from the engine manufacturer stating that the particular engine (engine number to be stated) cannot meet Catalyst emission limits, then use the pre cat limits of CO 3.5%, HC 1200ppm.
My car has a cat but the test was given as it hasn't got one??? Is it because it's an import???
My car has a cat but the test was given as it hasn't got one??? Is it because it's an import???
Texx
Super Moderator
In that case a CAT test should be carried out using the default limits, these are:
Fast idle: (2500 to 3000rpm)
CO <= 0.3%
HC <= 200ppm
Lambda 0.97 to 1.03
Idle: (450 to 1500rpm)
CO <= 0.5%
A CO reading of 0.47% taken during the fast idle test would result in a fail, this could be caused by a number of different reasons. A CAT in good shape operating efficiently could possibly bring the CO reading down below the limit of the test, but it's possible the O2 sensor isn't switching quick enough and so the ECU is lacking the ability to trim fuel fast enough when in closed loop operation. With regards to a low reading resulting in a MOT fail, I would guess the manager was getting a little confused between a low CO reading and a low Lambda reading.
OK. Thanks a lot for that! SO that should be less than 0.3% and I have 0.47% - therefore it's failed!!!!
What do I need to reduce the CO and pass it??? may be put some redex in and give it a good clean??? or any other alternatives??? reset the ECU may be??? I've cleaned the air filter already, oil was changed as well!
Texx
Super Moderator
The CAT is effectively a safety net for when things go wrong. Ideally when the engine and associated EFI components are working in good order, there is little for the CAT to do. It's only when something goes wrong that the CAT comes into play, it's role is to convert the majority of the toxic and harmful CO, HC and NOx gases into less harmful CO2, N2 (nitrogen) and H2O (water). However even when in good shape the CAT has it's limits, at most it can only convert 90% of the harmful gases and so if the remaining 10% or more is enough to fail the MOT emissions test then the initial cause of the problem needs to be addressed.
An excessive CO reading indicates that more fuel is present than can be consumed with the oxygen available, so it's either a case of too much fuel is being dumped in or the engine is being starved of air. If your confident the air filter isn't causing any restriction it would be worth checking the ignition timing is set correctly and not over advanced. If you don't find an issue with the ignition timing then I'd be inclined to replace the O2 sensor as it's possibly the most likely cause.
An excessive CO reading indicates that more fuel is present than can be consumed with the oxygen available, so it's either a case of too much fuel is being dumped in or the engine is being starved of air. If your confident the air filter isn't causing any restriction it would be worth checking the ignition timing is set correctly and not over advanced. If you don't find an issue with the ignition timing then I'd be inclined to replace the O2 sensor as it's possibly the most likely cause.
The ignition timing is perfect, I've checked that! Also it idles at 750 RPM which is spot on!
I've cleaned my Air Filter (k&n) just before the MOT!!! Apparently it had some oil.... so it's possibly the Turbo Oil seals!
Regarding the O2 sensor that could be the problem....
Some people suggest to give it a good half an hour drive before the MOT on the Motorway, I'll try that and then try to retest it!
Also if I take the air filter off just for the MOT testing - would that give more fresh air and provide better CO in theory??? or the EFI pipe will restrict it anyway....
I've cleaned my Air Filter (k&n) just before the MOT!!! Apparently it had some oil.... so it's possibly the Turbo Oil seals!
Regarding the O2 sensor that could be the problem....
Some people suggest to give it a good half an hour drive before the MOT on the Motorway, I'll try that and then try to retest it!
Also if I take the air filter off just for the MOT testing - would that give more fresh air and provide better CO in theory??? or the EFI pipe will restrict it anyway....
I can't see the pic you have uploaded.
so can't see what the car produced against limits or which test was used.
If it was me and the paper work/limits were met then I would be appealing through vosa.
If it failed then I would be looking at how it was tested, personally With imports I generally am very accommodating and use a non cat test if the model and engine code are not in the system or if the vehicle presenter should ask/expand on the car ;-)
so can't see what the car produced against limits or which test was used.
If it was me and the paper work/limits were met then I would be appealing through vosa.
If it failed then I would be looking at how it was tested, personally With imports I generally am very accommodating and use a non cat test if the model and engine code are not in the system or if the vehicle presenter should ask/expand on the car ;-)
So what should I say if I go to another MOT centre tomorrow???
Could you PM your Email and I will email you all the paperwork I was given!
Dear Mr J,
Thank you for your email dated 28th February 2011.
We apologise if you feel you have received a poor level of service from our Milton Keynes branch; we aim to maintain a consistently high level of service with both our products and customer service.
I have contacted the manager at our Milton Keynes Autocentre who has advised me that the vehicle has failed as the emissions were too low; he claims this was fully explained when you picked the vehicle up from the centre. The manager believed that you were going to externally rectify the vehicle’s faults and return the vehicle for a retest.
Please contact the Milton Keynes branch with regards to your vehicle; they will be able to further explain the emissions fault with your vehicle and if necessary have the vehicle returned to the centre. The contact telephone number for the MK branch is 01908 367 246.
Thank you for your email dated 28th February 2011.
We apologise if you feel you have received a poor level of service from our Milton Keynes branch; we aim to maintain a consistently high level of service with both our products and customer service.
I have contacted the manager at our Milton Keynes Autocentre who has advised me that the vehicle has failed as the emissions were too low; he claims this was fully explained when you picked the vehicle up from the centre. The manager believed that you were going to externally rectify the vehicle’s faults and return the vehicle for a retest.
Please contact the Milton Keynes branch with regards to your vehicle; they will be able to further explain the emissions fault with your vehicle and if necessary have the vehicle returned to the centre. The contact telephone number for the MK branch is 01908 367 246.
I think it should be the opposite way - I need more oxygen and less petrol so MY CO will go down..... Surprisingly the Air Filter has been cleaned just before the MOT! Going to another MOT centre in 2 hours, will see what they say!
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OK guys, passed with no advisory in another garage!!! CO was a bit high at first, but then he put it to high RPM for some time and afterwards it's gone down, funny though when the Radiator fan was on - the CO was going UP when it was off, it was going down.... obviously as the car was standing still it was on pretty often - but in real life it rarely kicks in - therefore it is not correct to measure while it's on!
Anyway it passed - HC was below 40, CO was below 0.3% - I believe the lambda sensor doesn't work properly on LOW RPM!
Thanks to everyone for your help and support!
Anyway it passed - HC was below 40, CO was below 0.3% - I believe the lambda sensor doesn't work properly on LOW RPM!
Thanks to everyone for your help and support!
TURBO2010
Member +
x2!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!