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Discussion Starter #1
Just had my 207cc 1.6 120HP MOT'd and it has failed on lambda emissions.

It has flown through on CO and HC readings (0.02 CO against an allowable max of 0.30 and 8 ppm HC against a max of 200), however the lambda reading on both the fast idle tests was over the maximum allowable 1.030, by just 0.021 and 0.025, which doesn't sound like a lot to me.

Any advice on how I can get the lambda reading down a bit to get me through the test?

many thanks in advance!
 

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Sound like a lazy Cat or O2 Sensor was the car fully warmed up (italian tune up to get the Cat hot)
 
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It has flown through on CO and HC readings (0.02 CO against an allowable max of 0.30 and 8 ppm HC against a max of 200), however the lambda reading on both the fast idle tests was over the maximum allowable 1.030, by just 0.021 and 0.025, which doesn't sound like a lot to me.
Welcome to the forum.

Have you got a record of last years emission test results? If you have post those up, it may help.
 

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Thanks for the speedy replies guys (and the welcome!).
Unfortunately I don't have a record of last years emissions test. This is the first MOT I have put the car through since buying it just under a year ago.
The MOT testers apparently took the car out for a good run to warm everything through before the second (and oddly, slightly higher) fail. So, yeah, Italian tune up!

It seems to me that since it has only failed on lambda and only by a small amount, a dose of cataclean or something similar might help.
Any thoughts?

Also. And I don't know if this will be of any help; the car has covered just over 54000 miles and drives very well, except for some "hunting" for a stable idle when the engine coolant is just coming off full cold (it's almost as if the ECU is "pushing in the choke" a tad too early). At full cold it idles fine and as soon as the coolant temp is up it idles fine. It's literally only hunting for a stable idle just as it starts to warm up.

The guys at the MOT test centre are recommending fresh spark plugs and an oil change, but I fitted new plugs less than six months ago (to try and help with the lumpy idle issue mentioned above).
Could an oil change really make much difference?
 

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Sound like O2 sensor could be failing as that can cause hunting at idle due to slow switching. However I'm sure they are wideband on the VTI and are silly money

Get it nice and hot before test. If it's like my daughter 1.6 vti it burns oil which reduces cat efficiency over time. My daughters would only just pass on lambda with all the other readings well within spec



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Discussion Starter #7
Well thanks for all the advice guys.
The car did eventually pass the emissions test after a dose of cataclean and an oil change.
It apparently took 3 attempts, but I think the testers just didn't get it hot enough on the first two tries. Final reading was 1.005, just 5 thousandths off of a perfect burn.
Happy days! Now all I need to do is address the other minor issues flagged up in the MOT!
 
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