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[Shelby]

Well, that time has come and is in the process of going ... hopefully.

Had it tested this morning and it has failed on emissions as shown below:

Fast Idle
CO <= 0.3% - actual 0.932%lamda: 0.97-1.03 - actual 1.081
Second Fast Idle
CO <= 0.3% - actual 0.893%lambda: 0.97 - 1.03 - actual 1.079

Any thoughts on what to look at?  I will paperclip test it tonight to see if it is showing any fault codes like the lambda sensor and post back as well.

Did get a couple of advisories aswell:

NSF/OSF brake pipe slightly corroded
NS/OS (Front to rear) brake pipe slightly corroded
Slight corrosion on underside
NSF tyre close to limit

I can live with those, is it standard practice to advise brake pipes, seem to get them all every MOT I do! haha

I was expecting it to fail for the NSF drop link and outer tie rod end.  Drop link knocks a bit of you try and move it so has a bit of play and the rubber over the outer tie rod end ball joint has come away slightly (parts are already ordered), funnily enough they didn't even pick up on those.  Aren't they part of the MOT?

[Gaffers]

Are is the manifolds or the exhaust blowing?

How old are is the cats?

Edited

[Shelby]

Exhaust isn't blowing that I am aware of, but will check.  The manifold gasket was replaced a couple of months back when I had to get a few broken manifold bolts out.

As to the age of the cat, your guess is as good as mine to be honest.  I think I have some receipts for when it was replaced at home (only had the car a few months), will check after work today, but don't think it's any more than a year or so old.

Had an oil and filter change a not this weekend just gone but the one before, and replace the plugs at that time.  Need to recheck the new plugs to see how it is burning as well as the old plugs had quite a bit of carbon deposit on them, again, don't know how long they had been in the car.

[Shelby]

OK, checked through the receipts I had for the car and a new cat was done in April 2008, so its just over 3 years old.

Would a failed cat put the CO emissions that far out?

I have checked for any fault codes and it isn't showing any at all don't get any flashes on the EML apart from it flashing on/off once quickly when I first turn the ignition on.

[big mel]

my mig failed on emmisions it was the cat. which was only 2yrs old'i was told cats only last 2yrs. the original was 6yrs old.

[Shelby]

Cat would make sense, I really could do without the expense right now though haha

[tigers_gonads]

I'd check that the lambda sensor is working ok 

Could be its running rich  :-/

[Shelby]

I was thinking of it possibly running rich as the old spark plugs were black all over the electrodes when I took them out.  The new ones pictured in this thread

http://www.omegaowners.com/forum/YaBB.pl?num=1310399819/0#4

are 200 miles from new, would they show much after that sort of distance if it was running rich?

Any way to check the lambda sensor beyond fault codes as the paperclip test isn't showing any faults?

Edit: Just seen you had replied on that thread anyway 

[aaronjb]

The lambda reading you're getting at the exhaust outlet indicates it's running lean, not rich.. so if it is running rich in reality there's a massive air leak into the exhaust somewhere.

My money would be on a leaking gasket or blown exhaust somewhere along the line, I think.

[tigers_gonads]

I believe you can see if the sensor is working by pluging into a tech 2 or similar then setting it up for live data 

Do it when the engine is cold.
That way you can check the coolant temp at the same time and see if the sensor readings change as the engine gets warm 

[Shelby]

Doing some research today on this today and a common one that comes up, for a possible cause of high CO, is a shoddy air filter.

I think im going to check the lambda sensor voltages tonight (I think it's pre-cat isn't it?) and see what the outputs are.  Hopefully that should give me an indication if the problem is pre or post cat.

Quite an interesting read here on emissions, well it was for me with little knowledge on the subject 

http://www.petercoopercarrepairs.co.uk/new_page_2.htm

[idc62]

i had my 4 pot mig MOT'D yesterday did emmissions test first and failed high co .579%, fail lambda 1.049 did rest of test with engine idleing ,passed all that no advisories gave engine good rev temp went to just over 90 deg redid gas test and passed CO .239% LAMBDA 1.015 and HC down from 77ppm to 43ppm he then said to me omega's run cool make sure you get up to temp with a good blast on motorway before test.Hope this helps you and mines on the road for another year whoopee!!!!!! 

[Shelby]

congrats, another one on the road for another year.

I had done a few miles to the test center (was at normal running temp on the gauge when he started).  When he did the tests he says he tested it 2 or 3 times at fast idle (was was sitting at 2.5-3k revs for a few minutes) and it failed consistently on each test.

When I drove the car away the temp gauge was around 95-97, that was after sitting for a few mins with engine off while I waited for paperwork etc.

I am leaning heavily toward the cat at the moment based on what I have read and what people have posted here.  I got the car up on a ramp last night and inspected the exhaust and externally its in good condition with no leaks / blowing, apart from I noticed that it has dropped a bolt from the bottom connection of the manifold that connects to the cat pipe (so only 2 bolts in place rather than 3).  These were replaced a couple of months ago with new bolts and gasket etc when I had the manifold off, so may have a bit of excess air getting in there but I don't think that would throw the CO up as high, could be helping to attribute to the slightly raised lambda though.

Think I am just going to have to take the hit on the cat cost and get it done, then retest it and see what happens, hopefully that will sort it or SWMBO bill have my balls in a vice as its our holiday money being burnt, but we need the car to go on holiday!

[Gaffers]

.......replaced a couple of months ago with new bolts and gasket etc when I had the manifold off, so may have a bit of excess air getting in there but I don't think that would throw the CO up as high, could be helping to attribute to the slightly raised lambda though......

If it is blowing, even so slightly it is difficult to tell, then this is the source of your high emissions.  For the price of a bolt and a basket, it's worth sorting before spending several times more on a new cat and/or exhaust.

[Shelby]

.......replaced a couple of months ago with new bolts and gasket etc when I had the manifold off, so may have a bit of excess air getting in there but I don't think that would throw the CO up as high, could be helping to attribute to the slightly raised lambda though......

If it is blowing, even so slightly it is difficult to tell, then this is the source of your high emissions.  For the price of a bolt and a basket, it's worth sorting before spending several times more on a new cat and/or exhaust.

I am getting the bolt today anyway.  Will be sticking it on tonight and then putting it through a retest tomorrow, if nothing else I can get an accurate reading on the emissions without that problem, was even considering taking the air filter out just for the test as I had read that a clogged airfilter can cause hi CO readings.  If it then passes, or makes quite a difference with the CO readings I can safely say I need a new air filter (which probably wouldn't hurt anyway to be honest).