MOT Failure - Emissions
Discussion
Hi all,
My MG ZT 1.8t (k-series) failed its MOT on monoxide emissions.
So far I plan to clean the lambda sensors, and change the oil, oil filter, and air filter.
Would it be worth changing the plugs while I'm at it?
I have a slight rattle coming from my exhaust which sounds like there's a bit of metal/a stone inside of it - Possibly the cat has broken up? They're not necessarily cheap so if I could avoid changing it when it isn't needed then that's ideal.
If it was a mechanical issue it wouldn't be so bad as I could physically see it, but without breathing in the gas from my exhaust beforehand and afterwards to see if it tastes less toxic, there's not much I can do
Any other ideas on how to sort it?
My MG ZT 1.8t (k-series) failed its MOT on monoxide emissions.
So far I plan to clean the lambda sensors, and change the oil, oil filter, and air filter.
Would it be worth changing the plugs while I'm at it?
I have a slight rattle coming from my exhaust which sounds like there's a bit of metal/a stone inside of it - Possibly the cat has broken up? They're not necessarily cheap so if I could avoid changing it when it isn't needed then that's ideal.
If it was a mechanical issue it wouldn't be so bad as I could physically see it, but without breathing in the gas from my exhaust beforehand and afterwards to see if it tastes less toxic, there's not much I can do
Any other ideas on how to sort it?
Sycamore said:
My MG ZT 1.8t (k-series) failed its MOT on monoxide emissions.
So far I plan to clean the lambda sensors, and change the oil, oil filter, and air filter.
Would it be worth changing the plugs while I'm at it?
I have a slight rattle coming from my exhaust which sounds like there's a bit of metal/a stone inside of it - Possibly the cat has broken up? They're not necessarily cheap so if I could avoid changing it when it isn't needed then that's ideal.
If it was a mechanical issue it wouldn't be so bad as I could physically see it, but without breathing in the gas from my exhaust beforehand and afterwards to see if it tastes less toxic, there's not much I can do
Any other ideas on how to sort it?
High CO, but HC and Lambda were good? That definitely sounds like cat - especially given the rattle.So far I plan to clean the lambda sensors, and change the oil, oil filter, and air filter.
Would it be worth changing the plugs while I'm at it?
I have a slight rattle coming from my exhaust which sounds like there's a bit of metal/a stone inside of it - Possibly the cat has broken up? They're not necessarily cheap so if I could avoid changing it when it isn't needed then that's ideal.
If it was a mechanical issue it wouldn't be so bad as I could physically see it, but without breathing in the gas from my exhaust beforehand and afterwards to see if it tastes less toxic, there's not much I can do
Any other ideas on how to sort it?
TooMany2cvs said:
Sycamore said:
My MG ZT 1.8t (k-series) failed its MOT on monoxide emissions.
So far I plan to clean the lambda sensors, and change the oil, oil filter, and air filter.
Would it be worth changing the plugs while I'm at it?
I have a slight rattle coming from my exhaust which sounds like there's a bit of metal/a stone inside of it - Possibly the cat has broken up? They're not necessarily cheap so if I could avoid changing it when it isn't needed then that's ideal.
If it was a mechanical issue it wouldn't be so bad as I could physically see it, but without breathing in the gas from my exhaust beforehand and afterwards to see if it tastes less toxic, there's not much I can do
Any other ideas on how to sort it?
High CO, but HC and Lambda were good? That definitely sounds like cat - especially given the rattle.So far I plan to clean the lambda sensors, and change the oil, oil filter, and air filter.
Would it be worth changing the plugs while I'm at it?
I have a slight rattle coming from my exhaust which sounds like there's a bit of metal/a stone inside of it - Possibly the cat has broken up? They're not necessarily cheap so if I could avoid changing it when it isn't needed then that's ideal.
If it was a mechanical issue it wouldn't be so bad as I could physically see it, but without breathing in the gas from my exhaust beforehand and afterwards to see if it tastes less toxic, there's not much I can do
Any other ideas on how to sort it?
TooMany2cvs said:
Sycamore said:
TooMany2cvs said:
High CO, but HC and Lambda were good? That definitely sounds like cat - especially given the rattle.
Yessir: "•Exhaust emissions carbon monoxide content after 2nd fast idle excessive (7.3.D.3)"
The rattle sounds like cat elements have come loose.
If this is the case and this is a shed, sometimes you can put a jack under the cat and slightly crush it to trap the loose element, stop the rattle and get it through test.
If it's not a shed, take the old cat to scrappy and buy a spurious/universal cat to replace it.
If this is the case and this is a shed, sometimes you can put a jack under the cat and slightly crush it to trap the loose element, stop the rattle and get it through test.
If it's not a shed, take the old cat to scrappy and buy a spurious/universal cat to replace it.
TooMany2cvs said:
Sycamore said:
TooMany2cvs said:
High CO, but HC and Lambda were good? That definitely sounds like cat - especially given the rattle.
Yessir: "•Exhaust emissions carbon monoxide content after 2nd fast idle excessive (7.3.D.3)"Mine failed with 0.54%
TooMany2cvs said:
Sycamore said:
Failed on CO. Max is 0.3%
Mine failed with 0.54%
What's the HC and Lambda?Mine failed with 0.54%
Lambda allowable is 0.95-1.09. I'm on 1.01.
Edit: CO passed on natural idle, with 0.49% (0.5 allowed) it failed CO on both fast idle tests.
Maybe it's overfuelling when revving /accelerating.
As you mentioned, Cat is likely. I'll give it a service this weekend and give it some cataclean and have it retested. If end up with another fail I'll just replace the cat.
Edited by Sycamore on Friday 22 September 17:31
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