Technical '07 GP 1.2 - Just failed MOT with leaky exhaust & high CO

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Technical '07 GP 1.2 - Just failed MOT with leaky exhaust & high CO

cancunia

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I'm wondering if a leaky exhaust at the flexi joint & silencer will cause high Carbon Monoxide levels, or is it something else?

MOT failure notes:
1, CO at idle excessive,
2, CO after 2nd fast idle excessive &
3, Lambda reading after 2nd fast idle outside specified limits.


The exhaust system will be changed as it's past repair anyway.

The car has been sitting idle for the best part of 3 months with just the odd start up to move it and idling for a few minutes. The MOT station is just about 5-6 miles away.
I've read elsewhere that a hard run will help things along with some new plugs?

Any thoughts much appreciated
 
I'm wondering if a leaky exhaust at the flexi joint & silencer will cause high Carbon Monoxide levels, or is it something else?

MOT failure notes:
1, CO at idle excessive,
2, CO after 2nd fast idle excessive &
3, Lambda reading after 2nd fast idle outside specified limits.


The exhaust system will be changed as it's past repair anyway.

The car has been sitting idle for the best part of 3 months with just the odd start up to move it and idling for a few minutes. The MOT station is just about 5-6 miles away.
I've read elsewhere that a hard run will help things along with some new plugs?

Any thoughts much appreciated

Would agree with everything you say. If car has been sitting for a while it will defo need a good long run, getting it up to full temp for some time. Pretty sure you would have got some errors thrown up if anything wrong with cat and or O2 sensors. Replace exhaust system and get Co2 levels checked after you've had it fixed. The take on a good long run...30 minutes minimum and give it some welly.
 
Thanks for the quick replies. I spoke to the MOT tester this morning, he thinks the exhaust will be putting off the readings too and offered to to a quick retest once I've sorted the exhaust.

The fuel reserve light is on so I'll sort the exhaust, get some premium fuel put in and give it a good run on the way to the re test.
 
A cracked exhaust manifold may also cause the same symptoms. Hopefully it's not the case here.
 
Passed the MOT this morning. I fitted the new exhaust, changed the oil & filter, cleaned & gapped the plugs and gave it a good high revs run for about 30 mins before the test. CO results on the fast idle were only just within limits, but it did pass which is what counts. The MOT man suggested that the CAT is on it's way out. My guess is that he may be right but what he didn't know was the car had not really been anywhere for 3 months, so a bit more driving around may improve it a bit more still. Apparently it was way beyond limits when he tested it last week, seems that the 'Italian Tuneup' method does have some effect if you fail your emissions.
 
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Thaks for letting us know, that's useful feedback! I agree with your plan - run it for another year and see what it's like at the next MOT. I've always been a fan of the "Italian Tuneup". Cats do need to get stinking hot to do their job.
 
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