MOT emissions Failure with a 200 Cell Sports Cat - Help!!

[nw66]

As long as it's registered before aug 1995 anyone can use this loophole, I have a aby coupé registered April 93.

I fabbed up a v banded cat for the test but turned out I didn't need it.


IMG_20231014_182401.jpg

Very high flow cat on the left!

The stainless core cats really don't get up to temp easily and don't stay hot for long. And they really only work for about 6 months worth of driving before the matrix is not effective.

Ceramic core is what standard cats are made from and easily get to temp and stay hot but are easily damaged. Finding a 3 inch one was a challenge!

I'm based in Bournemouth if anyone wants help with this kind of setup just ask. It's all a hobby for me (out of my 1.5 car garage) so just paying for just materials and argon happy to help.

As to the problem here, any (more modern) standalone should be easily setup to run in closed loop fuel correction to stoic as a !TEMPORARY MAP! for MOT testing using any wideband / narrow band sensor.

Best guess here is bad lambda sensor, be careful of it running rich all the time. It ruins the engine oil fast, if the dipstick smells of v-power time to change even if it looks clean!

Cool thanks for info..


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[Chris5044]

This does point at the Llambda sensosr. Surprised it's not a wideband.

My lambda sensor is a wide band and was installed for the initial tune of the car a few years ago

[Chris5044]

Just a bit of info for everyone, if you have a coupé registered on or before 1 august 1995 you can have a non cat test with much wider limits simply by sticking a ADU sticker on the cam cover.
The only engine listed in the ega database for S2 is 3b. So you can point that out to the MOT test inspector.

Here's a link to the inspection manual.

https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles

All the info is listed under nuisance.

Screenshot_20231217-095201.jpg

ah thx buddy!! mine was registered January 1996 ... I don't qualify!! doh!!!! thanks for trying though!!!

[Chris5044]

As long as it's registered before aug 1995 anyone can use this loophole, I have a aby coupé registered April 93.

I fabbed up a v banded cat for the test but turned out I didn't need it.


IMG_20231014_182401.jpg

Very high flow cat on the left!

The stainless core cats really don't get up to temp easily and don't stay hot for long. And they really only work for about 6 months worth of driving before the matrix is not effective.

Ceramic core is what standard cats are made from and easily get to temp and stay hot but are easily damaged. Finding a 3 inch one was a challenge!

I'm based in Bournemouth if anyone wants help with this kind of setup just ask. It's all a hobby for me (out of my 1.5 car garage) so just paying for just materials and argon happy to help.

As to the problem here, any (more modern) standalone should be easily setup to run in closed loop fuel correction to stoic as a !TEMPORARY MAP! for MOT testing using any wideband / narrow band sensor.

Best guess here is bad lambda sensor, be careful of it running rich all the time. It ruins the engine oil fast, if the dipstick smells of v-power time to change even if it looks clean!

I have now changed the alternator as the voltage was jumping up and down a bit.. Ive added injector cleaner to the fuel, and cleaned the MAF. Next i will clean the Idle control valve and change the spark plugs..

The wide band lambda sensor is only a few years old and bought from the tuners.. so I doubt that. unless it has indeed gone. which I'm not happy about...
I'll check the oil smell as you stated.. But I may ask you for your services If you can fabricate these exhaust parts.. As the V-band swap exhaust was an option..
Massive thankyou Quattroking - I dont live too far from you, (Guildford).

[Quattroking]

More than happy to help Chris5044, I'll pm about details.

I don't keep much "on the shelf" as it were, so would need detailed measurements for tube and overall cat sizes. Happy to do them down my way.

Lambda sensors can be tricky, do you know if you have a LSU 4.2 or LSU 4.9? The 4.2's need regular free air calibration, every 3 months or so with weekend use. It's due to there design, they have a small amount of reference air in them that degrades. OEM ECUs have very complex compensation tables for lambda sensors that affordable aftermarket ECUs do not.

Anyway I'm amazed that you managed a few good years out of a sensor! They always seem to be a bit disposable for me, even when I take good care over there location and heating!

It's a good start with some of the service items, I'd check that the fuel pressure reg is doing what it's supposed to. I haven't worked with an emerald before but I'd be surprised if they use the maf sensor to load calculate, I'd imagine it's standard speed density ( happy to be proven wrong!).

I do have a ultrasonic injector cleaner setup, but there is a risk breaking the old ones getting them out. Plus new orings ect.

[Chris5044]

I double checked with the tuners today. They said the car is running fine. Its just high on CO2 because I need a catalytic converter. The sports cat isn't quite passing the MOT. They know what they are talking about gave me reassurance.

[Tractor Dave]

Looking at your results I totally disagree with that

[nw66]

I double checked with the tuners today. They said the car is running fine. Its just high on CO2 because I need a catalytic converter. The sports cat isn't quite passing the MOT. They know what they are talking about gave me reassurance.

Mmmmm


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[Davi123]

Be really interested to see what the solution is. Mine always seems to just pass on high CO2 and I’m sure the time will come when I’m in the failure zone!

[Quattroking]

I'm not disagreeing with anyone just want to offer up some facts.

Below is my last MOT running on motronic with no cats at all. (Unknown mtm tune and ev6 injectors) during the test my calibrated wideband stayed between .98/1.03 .



Here is a graph that shows Co (carbon monoxide) production Vs air fuel ratio.

airfuel.jpg
Basically the further away from stoic in the rich direction the more Co produced.

[newsh]

I'm not disagreeing with anyone just want to offer up some facts.

Below is my last MOT running on motronic with no cats at all. (Unknown mtm tune and ev6 injectors) during the test my calibrated wideband stayed between .98/1.03 .



Here is a graph that shows Co (carbon monoxide) production Vs air fuel ratio.

airfuel.jpg
Basically the further away from stoic in the rich direction the more Co produced.

Your first image is not showing.

[Quattroking]

IMG_20231223_090421__01.jpg first image upload again.
Like if it can be seen this time!

[merlin's S4]

Just a bit of info for everyone, if you have a coupé registered on or before 1 august 1995 you can have a non cat test with much wider limits simply by sticking a ADU sticker on the cam cover.
The only engine listed in the ega database for S2 is 3b. So you can point that out to the MOT test inspector.

Here's a link to the inspection manual.

https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles

All the info is listed under nuisance.

Screenshot_20231217-095201.jpg

Do you happen to know if the 100 S4 AAN engine is in the EGA database? Hoping for a similar loophole. My 100cel Cat hasn't passed the Cat test since it was new.

[Quattroking]

Here's a link to the database doc, it gets updated now and then so worth a look every time.

https://www.gov.uk/government/publications/in-service-exhaust-emission-standards-for-road-vehicles

The 100 ur S4/S6 only has the AAN listed so the sticker trick should work, as long as registered before 1 aug 1995.

[DeS]

The stainless core cats really don't get up to temp easily and don't stay hot for long. And they really only work for about 6 months worth of driving before the matrix is not effective.

Hey,

does it mean its only not "cleaning" the exhaust gases as it should or also blocking the flow?

Cheers!