[Corsa D 2006-2014] MOT Emissions Fail - any advice?

[rutherford12]

Hi Everyone,

2007 Corsa VXR failed its MOT recently due to emissions - both lambda readings (1.072 and 1.056) were too high (>1.030). As you can see from the pic, Engine speed, CO & HC all passed fine:



Does anyone have any advice for next steps before I spend £1,000 replacing the exhaust and cats from the turbo back? Any chance replacing the lambda sensors is a likely fix? I know that there are some small leaks at the center and rear silencers but my limited knowledge of the Corsa exhaust system tells me that the lambda sensor readings would have occurred before exhaust gases reach this point... (?).



Thank you for any help you can provide!

David

[Restorer]

As long as there are no leaks in the exhaust system at the cat and between the two lambda sensors. Because a small leak would push it just out of limits, like yours. What I would do is pour some cat cleaner in the fuel tank when you have about a quarter of a tank as the least fuel mix you have, the cleaner works better. A range a retest and about half hour before the test give the car a good run and get the engine nice and hot . And I'm sure the lambda readings would come down.
let us know how you get on

[Restorer]

Here's the one I use .

[Restorer]

h

[Restorer]

[rutherford12]

Thanks for this! I’ll get the car up on jacks to have a quick look where any holes are, repair as necessary then I’ll pick this stuff up. Will let you know how I do.

[everson38]

Thanks for this! I’ll get the car up on jacks to have a quick look where any holes are, repair as necessary then I’ll pick this stuff up. Will let you know how I do.

How did you get on with this in the end?

Sent from my moto g(8) plus using Tapatalk

[rutherford12]

Hi guys,

Had the Corsa up on stands during the week and had a go at sealing the holes in the exhaust - probably didn't get them all (or even get the obvious ones properly) but there does seem to be a healthier noise and more gas coming out of the exhaust tip compared to before.

Took it to the MOT yesterday after putting the Cataclean through it - I genuinely can't say if it worked or not as these were the results from the garage:






With the lambda result at 1.030 I can't say whether the Cataclean made me pass or the garage did. Thoughts?

[jt999]

I had a similar issue with my old Impreza, ran a cat cleaner and took it for a bit of a spin thinking it wouldn't make a difference but it was enough for it to pass, just!