Failed MOT on CO2, LAMBDA is marginal.

[Tom Clarke]

Hi all,

As the title says my 182 has failed MOT on CO2 emissions, the LAMBDA reading has not caused it to fail, but is apparently high, the HC level is apparently normal.

Background on the car -

Engine rebuilt last year,
428 Catcams
KTR port matched inlet manifold
KTR sportcat (which says it's emission passable)
KTR centerline catback system
ITG panel filter

I've sprayed the exhaust system from front to back with soapy water looking for leaks, nothing is immediately obvious, although it's very hard to see the exhaust manifold where it bolts to the block. The exhaust manifold is original, whereas everything back from there is less than a year old and was professionally installed.

There are no fault lights on the dash, O2 sensor light has never even flickered on.

Looking for advice on what might be the cause.

Does anyone have the KTR sportcat fitted and can they comfirm it is indeed emissions passable?

Has anyone had similar high CO2 and LAMBDA readings and knows the cause?

Can anyone offer some informed speculation on what the problem may be?

Very grateful and appreciative of any advice, many thanks in advance!

Tom

 

[Dex90]

I don't believe they use your actual 02 sensor on your car they use a probe. I would get it plugged in to Renault clip and see what your pre cat lambda sensor is reading. It's propably just that that needs changing if you have no exhaust leaks

Sent from my Moto G (5) Plus using Tapatalk

 

[bloke]

What was the figure and did they just start test or hold higher idle to get figures down?

Could be how it's mapped, lambda sensor iffy etc.

 

[Tom Clarke]

The garage got it as hot as possible and did everything they could to try to get it to pass apparently.

Here are the actual MOT emissions test details:



Hope that means more to somebody else than it does me! Appreciate the replies, thanks both.

 

[bloke]

any idea if they kept idle high for a few minutes?

 

[Tom Clarke]

any idea if they kept idle high for a few minutes?

To be completely honest I'm not sure. What's the purpose of doing so? Just to get more heat into the cat?

 

[bloke]

gets emissions to settle down, some just fly through others need a bit of messing with. without knowing or looking at live data for lambda sensor i'd guess possibly 200 cell cat and cams not helping.

 

[Allan H]

Had similar emissions problems- new pre-cat lambda sorted it. Garage was a friendly one too!

 

[Tom Clarke]

Many thanks for these replies.

I've got a pretty bog standard code reader, gives me live O2 data, might plug that in and see what readings I'm getting from the pre cat sensor, then borrow the pre cat sensor from my brothers 182 and see if the data is very different in an attempt to eliminate the sensor (or hopefully find a faulty sensor!)

The garage I use is pretty good, over the ten years I've been using them we've taken cars there that've failed emissions elsewhere and they've given them a good run and got them to scrape through.

Over the next two days the garage are having a look at it and I'll try swapping the O2 sensor. Either way once it's resolved I'll post the solution up here in case anybody else has similar issues in the future.

 

[bloke]

graph it, chances are it's slow switching.

 

[Tom Clarke]

Been troubleshooting this issue. Unfortunately this isn't going to be much help to the majority of people experiencing this issue since the problem seems to be pretty specific to my car/engine spec.

Checked exhauat and intake for leaks, non found. Changed O2 sensor post cat, no difference in readings, changed pre cat sensor, still the same. Eventually phoned Ktec and asked how legit the 200cell sport cat is, they said it should be well within tolerance and that they see them pass MOT all the time. After a bit of a chat we decided most likely cause is the current "safe" map that the car is running since the rebuild with the new catcams, which is probably over-fueling. Stopped driving the car to avoid ruining the new cat and booked it in for a tune at Ktec. Will update if there is anything to update but fairly confident this will remedy the issue. Sorry this isn't much use to people running a stock setup!

 

[bloke]

i doubt you could kill a 200 cell cat?

 

[masekwm]

My KTec cat fails mots too, has to go in HOT. Not hot reving it on the ramps, hot off the road, straight onto the test machine.

 

[Landyman]

I was going to suggest giving the car a good workout before you take it for the MOT.

 

[Stanneman]

Hi all,

As the title says my 182 has failed MOT on CO2 emissions, the LAMBDA reading has not caused it to fail, but is apparently high, the HC level is apparently normal.

Background on the car -

Engine rebuilt last year,
428 Catcams
KTR port matched inlet manifold
KTR sportcat (which says it's emission passable)
KTR centerline catback system
ITG panel filter

I've sprayed the exhaust system from front to back with soapy water looking for leaks, nothing is immediately obvious, although it's very hard to see the exhaust manifold where it bolts to the block. The exhaust manifold is original, whereas everything back from there is less than a year old and was professionally installed.

There are no fault lights on the dash, O2 sensor light has never even flickered on.

Looking for advice on what might be the cause.

Does anyone have the KTR sportcat fitted and can they comfirm it is indeed emissions passable?

Has anyone had similar high CO2 and LAMBDA readings and knows the cause?

Can anyone offer some informed speculation on what the problem may be?

Very grateful and appreciative of any advice, many thanks in advance!

Tom

Yes I have, not with the changes you made but i got similar problems with the MOT (APK in the Netherlands)
Correct my english if there are some faults in my typing

I have tried many things, new lambda new bougies cleaned the intake and injectors etc.

My solution was to put an extra ground cable directly from the battery to the exhaust as near as possible to the lambda sensor.

Hope it helps you as it did for me.

Greetz Stan

 

[flebay]

My solution was to put an extra ground cable directly from the battery to the exhaust as near as possible to the lambda sensor.

Never heard of anyone doing this before?

 

[bozothenutter]

I used to have trouble passing the gas test here in Holland aswell, (for years actually....) ended up being a tiny leak in the exhaust, (not on a joint, but on the edge of a silencer where it occasionally hits sleepers) had it welded and it passes easily now.
This is on a remapped 182 with RS2 200cell cat and milltek.

switch the front lambda with the rear?
use a wideband to check the map?