Topic

OK Folks

Car has just failed MOT on emissions

Before I go throwing money at the problem, can I get some views of likely culprits

Here are the figures from the tests:

Fast Idle: CO 1.61% (Max 0.20%) Fail; HC 96ppm (Max 200) Pass; Lambda 0.95 (0.97 - 1.03) Fail
2nd Fast Idle: CO 1.43% Fail; HC 83ppm Pass; Lambda 0.95 Fail
Natural Idle: CO 3.00% (Max 0.30%) Fail

I am aware of a leak in the exhaust manifold gasket area (since having work on head done) which could be contributing.

Do people think new Cat is required?

No OBD codes came up when I checked.

Thoughts please

Oh, and I'll still be at FRL as old MOT doesn't run out until the 23rd!

No point worrying about anything until the leak is solved mate.

Regards,
Andy

Could the leak account for these readings on it's own, do you think?

John, be very careful driving it til it's fixed and mot'd. In the eyes of the law and your insurer, it's not roadworthy. A bit of a grey area, and no real problems unless you have any sort of incident, just thought I'd mention it.

F's are notorious for emmision failures, my MOT place doesnt even bother running my emmsions.

A leaky exhaust will cause a high O2 reading as it draws in air from outsude of exhaust, had it once on an astra.

Start by getting a good seal on your manifiold.

Hi John,

You are not having much luck recently. I'm sure the advice to sort out the leak first is good - is the leak a result of the work done or discovered during the work?

The figures quoted in your post are the default figures - did the tester try to find vehicle specific figures? - I don't know whether they are more favourable but I don't suppose the CO reading allowed would be any where near that high.

Here is a bit of info off the MOT site: http://www.motuk.co.uk/images/730_newp11.pdf

Richard

John,

Just another thought....this is the non-cat test figures which allow a much higher (3.5% CO) so if you are still having problems once your leak is sorted, it may indeed point towards a cat failure....not that I'm an expert!

http://www.motuk.co.uk/images/730_newp9.pdf

Richard

Thanks Richard - hadn't realised they were default figures!

However, having looked up the figures for MGTF 1.8i it makes very little difference!!

For future reference for others they are: (All at an oil temp of at least 70 deg)

Normal Idle speed max CO = 0.5%
Fast Idle Max CO = 0.3%
Max HC - 200ppm
Lambda acceptable range = 0.95 - 1.09 (so this would make my lambda readings a pass!!)

James has agreed to come back and sort exhaust manifold gasket, as this should have been sorted when he did the head

So I'm going to wait for that, and then get the emissions retested, before committing to a new Cat.

Watch this space

By the way the page for the info is http://www.dft.gov.uk/vosa/repository/Emissions%2017th%20Edition.pdf

Cheers,

John

yuor car doesnt have a TT exhaust does it? There have been threads about fails with those on here.

Stan_B wrote: wrote:

yuor car doesnt have a TT exhaust does it? There have been threads about fails with those on here.

No Stan - just a Toyosports (they push exhaust fumes out of both pipes!)

Thanks for thinking to remind me though

Just a quick one.....when i put my f through the MOT it almost failed as they have one test for petrol and diesel cars like a one test fits all. however they have an option to put your exact vehicle make and model in. when he done this it flew through. it will be worth asking if he put your exact vehicle in instead of just the one type fits all.

Thanks Bluelight - if you scroll up, you will see that this has been discussed.

Having said that, I was unaware until now that there were unique settings for each make and model - so cheers