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[pauldmackay]

I've had issues with the damn p0420 code since I bought the car.  The
previous owner had changed the full exhaust but the downpipe only has 1 main cat compared to the orginal pre-cat/main-cat set-up.

MOTed today, passed no problems.  8-)

Emissions reported as -

Fast Idle
CO 0.15%  (max limit 0.20%
HC 71ppm  (max limit 200ppm)
Lambda 1.002 ( should be between 0.970-1.030)

Idle  
CO 0.16%  (max limit 0.30%)

MOT was carried out by Council Mot station.  Emission light was on throughout the test too as it came going to the MOT station and I forgot teh damn reader.

So what to do now about this p0420, google search shows many websites stateside with electonis fixes blah blah anyone tried them, I could just remove the bulb and reset it now and again, but don't want to give up yet.

[Kevin Wood]

MOT emissions test will always pass if you have a working cat in the exhaust. The post-cat lambda sensor monitors emissions from the pre-cats only. Main cats are sufficient to get an MOT pass.

The fix for the emissions light is to relocate the post-cat lambda sensors behind the main cats.

Kevin

[Marks DTM Calib]

I have to say that the CO readings are disapointingly high for a cat equipped car.

[pauldmackay]

Yup read the fix, but I've only got 1 cat, so the post-cat lambda is a after the main the cat on the exhaust.

Set up is I don't have a pre cat at all, so I've got the downpipe with the lambda in the engine bay, no precat, then the main cat/only cat in the normal place and  then followed by the post cat lambda, that's it, so the post cat lambda is the 1 and only cat.  :-/

[pauldmackay]

I have to say that the CO readings are disapointingly high for a cat equipped car.

I've changed both lambda's, twice now.  I'll have a look into this further though as possibly linked to causing the emission light?  Just don't want to be changng anything else unless is actually needed, if I was needing to change cat I would go back to the 2 cat set up to keep it orginal.  Cars fully serviced new filters and full economy average 30.4mpg over the last 3200 miles.

[Marks DTM Calib]

I have to say that the CO readings are disapointingly high for a cat equipped car.

I've changed both lambda's, twice now.  I'll have a look into this further though as possibly linked to causing the emission light?  Just don't want to be changng anything else unless is actually needed, if I was needing to change cat I would go back to the 2 cat set up to keep it orginal.  Cars fully serviced new filters and full economy average 30.4mpg over the last 3200 miles.

Would doubt its the sensors, rarely ever is!

CHeap horrible nasty after market cat is the most likely cause.....which, sadly, would have been fitted for little more than a blowing flexi joint I would wager

[pauldmackay]

I have to say that the CO readings are disapointingly high for a cat equipped car.

I've changed both lambda's, twice now.  I'll have a look into this further though as possibly linked to causing the emission light?  Just don't want to be changng anything else unless is actually needed, if I was needing to change cat I would go back to the 2 cat set up to keep it orginal.  Cars fully serviced new filters and full economy average 30.4mpg over the last 3200 miles.

Would doubt its the sensors, rarely ever is!

CHeap horrible nasty after market cat is the most likely cause.....which, sadly, would have been fitted for little more than a blowing flexi joint I would wager

Yup, previous owner  had a whole new system fitted for 300 pounds brand is Walker, it is quiet though, it's coming off soon anyway, want original cat and then stainless steel cat  back, alway get this done to any car I've had, saves this hassle.

[ians]

I have to say that the CO readings are disapointingly high for a cat equipped car.

Mark - do you mean for the Omega in general, or this specific vehicle?

[Marks DTM Calib]

I have to say that the CO readings are disapointingly high for a cat equipped car.

Mark - do you mean for the Omega in general, or this specific vehicle?

I would say in general, particularly on the fast idle test

[Proz]

Yup read the fix, but I've only got 1 cat, so the post-cat lambda is a after the main the cat on the exhaust.

Set up is I don't have a pre cat at all, so I've got the downpipe with the lambda in the engine bay, no precat, then the main cat/only cat in the normal place and  then followed by the post cat lambda, that's it, so the post cat lambda is the 1 and only cat.  :-/

I have the same set up and almost every journey now this lights up  .... my mot due soon aswell but i think i'll try original downpipe with pre-cat and new sensors as a final throw of the dice ... if that fails then she is going to be sold ... spending too much on this car now ....