# MOT Failure on Emissions



## stevensred5 (Sep 3, 2010)

Can anyone suggest whats wrong with my emissions, I'm praying its not the CAT but things are pointing that expensive way, the results are:

Fast Idle-
CO% act=2.289 (allowed 0.300 max), 
HC act=303 (allowed 200 max) 
Lambda act=0.933 (allowed 0.970 min),

so the CO & HC are high & the Lambda is too low. Could this just be too rich a mixture, i.e. dodgy MAF, or is it defo the pussy, there is no warning lights on & obviously it was fine last year...any help


----------



## jamman (May 6, 2002)

I might be wrong but that CO is massive


----------



## stevensred5 (Sep 3, 2010)

Yes I know its high, gona clean the MAF & put a bottle of Redex in, I just read somewhere else that if the Lambda is too high its that & if the CO is too high its prob the cat


----------



## Gazzer (Jun 12, 2010)

stevensred5 said:


> Yes I know its high, gona clean the MAF & put a bottle of Redex in, I just read somewhere else that if the Lambda is too high its that & if the CO is too high its prob the cat


what is your temp reading? if it isn't hitting 90 then thermostat is gone and engine will stay in warm up mode....higher fuel usage and emmisions.


----------



## millepeed (Dec 29, 2011)

run petrol down to about 2-3 gal then put a bottle of cataclean in go for a 10-15 mile run then take to mot station. make sure when they test engine is at 90deg running temp. check this with 49c test. this has always sorted my cars in the past with worse numbers then you have.


----------



## Spandex (Feb 20, 2009)

millepeed said:


> run petrol down to about 2-3 gal then put a bottle of cataclean in go for a 10-15 mile run then take to mot station. make sure when they test engine is at 90deg running temp. check this with 49c test. this has always sorted my cars in the past with worse numbers then you have.


He should probably try to work out what's wrong with the car, rather than just work out how to pass the test...


----------



## TT-TOM (Feb 15, 2012)

I would scan it for faults first


----------



## Bartsimpsonhead (Aug 14, 2011)

stevensred5 said:


> ?..the results are:
> Fast Idle-
> CO% act=2.289 (allowed 0.300 max),
> HC act=303 (allowed 200 max)
> Lambda act=0.933 (allowed 0.970 min),


Just got mine MoTd at the beginning of this month with the test results as below:
FAST IDLE-
CO; (Limits) Max 0.20% - (Reading) 0.00% - Pass
HC; (Limits) Max 200ppm - (Reading) 16ppm - Pass
Lambda; (Limits) 0.97-1.03 - (Reading) 1.03 - Pass

NATURAL IDLE-
CO; (Limits) Max 0.30% - (Readin) 0.00% - Pass

I thought it'd be a lot worse than that as I've just had a Blueflame 3" down pipe fitted and a Revo II map, but I guess with the remap its burning a lot cleaner than it was before, and the new 200c cell Cat on the downpipe's hoovering up whatever else's left


----------



## stevensred5 (Sep 3, 2010)

Thanks for the replys, will put the cataclean in and redex and clean the maf......The oil temp was 83c ..correct me if I'm wrong but on my exhaust there is only one lambda, at the down-pipe, so logically as I have a bad reading there the emmissions are already no good before they get to the big cat, so my problem must be at the engine mixture side? ...or the cat in the downpipe? She does seem to be using a little more petrol recently but nothing to give me concern


----------



## ades tt 180 (Jun 19, 2011)

You need to do 49c-engine coolant temp not 51c-oil temp.


----------



## mighTy Tee (Jul 10, 2002)

Do you do only short runs?

If so take the car for a 30+ mile (legal) high speed blast to burn all the crap of the cat. At 3 years old mine only just passed the emissions test due to lack of use. Since I have always had a long motorway journey prior to MOT and the emissions are always on the low end of the scale.


----------



## stevensred5 (Sep 3, 2010)

The car does 12 miles to work & 12 back 5 times a week, never used on a wekend, just ordered some cat-clean, will put it in on the morning of the re-test, the garage I use for mots arent Audi experts and I 'suspect' they tend to throw parts at cars to solve probs, thats why I havent just told the garage to get on with it


----------



## mighTy Tee (Jul 10, 2002)

stevensred5 said:


> The car does 12 miles to work & 12 back 5 times a week, never used on a wekend, just ordered some cat-clean, will put it in on the morning of the re-test, the garage I use for mots arent Audi experts and I 'suspect' they tend to throw parts at cars to solve probs, thats why I havent just told the garage to get on with it


My commute and daily use is very similar, so it is worth taking the car for a good long drive. I normally tie my MOT in with a service at APS - this involves a 100 mile journey to them on mainly Motorway a dual carriageway so I can guaranty the CAT has been thoroughly heated and the crap has been burnt off.


----------



## Mondo (Feb 20, 2009)

Bartsimpsonhead said:


> ...CO; (Limits) Max 0.20% - (Reading) 0.00% - Pass...


Mine was similar MOT before last, on standard zorst. Reading of about 0.02%. Just did my MOT a few months ago, now I've a custom TSR exhaust with a 200-cell cat. Only just passed, with a CO2 reading of 0.29% 

Have noticed my 49C temp is only around 82C lately. It's easy enough to change the sensor, so I might do that. :?


----------



## stevensred5 (Sep 3, 2010)

Again thanks for the replys, will report back next Friday after mot


----------



## Olie055 (Nov 23, 2007)

Hello everyone. Got exactly same problem, went to MOT and the readings were even worst. Took car to garage to find out the turbo housing is cracked. So got a new turbo fitted. Now there is no smoke from exhaust what so ever but the figures are nearly exactly same as posted
CO% act=2.289 (allowed 0.300 max),
HC act=303 (allowed 200 max)
Lambda act=0.933 (allowed 0.970 min),
Thinking if it may be stuck in warm up mode as someone mentioned before. Is there any way how to somehow make car thinks it has been warmed up already without changing stat? As there might be problem with cat as well. My oil pressure is dodgy as well but hope this wont affect the warm up mode.


----------



## Hoggy (May 8, 2002)

Hi Olie, What temperature is the coolant getting to & Is the engine actually running cool? 
Running stationary for the MOT should cause it to reach running temperature.
The coolant temp sensor controls the mixture when cold so perhaps replacing that may help the emissions.
I'd be more worried about the dodgy oil pressure.
Hoggy.


----------



## EddieMunster321 (Jan 14, 2016)

Olie055 said:


> Is there any way how to somehow make car thinks it has been warmed up already without changing stat?


Nope; it's a simple device with a wax cylinder in it. More than likely yours will be a cheap OEM copy, and/or a cheap OEM copy temperature sensor; remove both, throw them in the bin, fit genuine Audi every time. There are literally 100s of posts on this forum where people have used cheap OEM thermostats, only to find they open/close too early/too late and consequently the car doesn't drive properly.


----------



## Olie055 (Nov 23, 2007)

Thank you. Dont know the temp yet as car is still on MOT place. Will find out soon. Will change the temp sensor or sensors are there 2 of them and stat. Oil pressure is OK checked it with mechanical gauge and ordered genuine audi one already. Do you think I have to put resistor in place of SAI (N112) or it wont make difference? Thaaank you


----------



## silverbug (Jan 1, 2020)

EddieMunster321 said:


> Olie055 said:
> 
> 
> > Is there any way how to somehow make car thinks it has been warmed up already without changing stat?
> ...


Completely agree about the thermostat , only ever fit a Genuine VW/Skoda/Seat/Audi item bought from a known & reputable source (like a VW /Audi main dealer trading on eBay or a bricks & mortar dealership ) as they're so much of a pain to replace and plenty of faulty/fake "Genuine" parts on eBay .
I had a fake/faulty "Genuine " coolant temp sensor from eBay that led me on a merry dance for a while last year .
Replaced it with a German Beru brand CTS (I couldn't find a Genuine one from a reputable source at that time) and it has been perfect .


----------



## StuartDB (Feb 10, 2018)

The fact you have deleted the SAI means it is not the EGT sensor... did you get the correct turbo assuming it is an APX? Needs to be a K04-22 or a K04-23 + a bolt blocking the EGT sensor hole.

Did the original thread poster confirm whether the MAF or coolant sensor was the issue?


----------



## Olie055 (Nov 23, 2007)

Just returned from MOT with the car. 51c shows 90 degrees and 49c was max 74 on idle but while driving dropped to 65ish. Im lucky owner of same TT with same APX engine so swapped the temp sensors and now on idle its 89 while driving 80 and going up the hill 93. The turbo is correct and I have no idea about EGT blanking or SAI delete. Bought this Roadster couple of months ago and its complete ripoff  Someone have deleted N112, N249 and god knows what else. There is also catch can installed cheap one. It would take me some time to find out whats not wrong about the car  And no reply from original poster
Thank you



StuartDB said:


> The fact you have deleted the SAI means it is not the EGT sensor... did you get the correct turbo assuming it is an APX? Needs to be a K04-22 or a K04-23 + a bolt blocking the EGT sensor hole.
> 
> Did the original thread poster confirm whether the MAF or coolant sensor was the issue?


----------



## Hoggy (May 8, 2002)

Hi Olie, Forget about using Code 51 as it always settles at 90
If coolant temp Code 49 drops below 80 during steady reasonable speed driving then replace thermostat with 87 degree OEM part No. 050121113C
Did it pass the MOT?
Hoggy.


----------



## Olie055 (Nov 23, 2007)

Hey Hoggy no haven't passed at all 
Will try to change stat tomorrow but I'm afraid the problem is in the N122, N249 removing. I think engine is in warm up mode but could be 1000 other things. I'm getting lost as I haven't done any mods myself and worst part is I cant take it to any garage as they wont have any clue whats happening with that engine as quite few thing are missing  This car was just mistake but I will do my best to save her 



Hoggy said:


> Hi Olie, Forget about using Code 51 as it always settles at 90
> If coolant temp Code 49 drops below 80 during steady reasonable speed driving then replace thermostat with 87 degree OEM part No. 050121113C
> Did it pass the MOT?
> Hoggy.


----------



## Olie055 (Nov 23, 2007)

Just had a look and found out that SAI is still there but N112 is missing and the vacuum pipe from top of the combi valve has been blanked. N249 has been deleted as well. No resistors used so this might be the problem as its not adapting. Another strange thing is catch can. Both hoses from rocker cover and oil filter housing are going to the catch can inlet and there is one hose going from the outlet of the catch can to the fender  Thats it. The puck is missing and the hose that should connect to puck is blended as well. Any thoughts? Thank you. Slowly getting there


----------



## davebowk (Aug 16, 2019)

Pipe into the fender (catch can outlet) can go to a puck then into TIP.

N249 delete won't affect emissions unless its not done correctly and not sealed (vac or boost leak)
Mines a BAM so don't have an N112, but as i understand it, if it's sealed then this won't affect emissions when it's at temp.
Don't think resistors missing will effect the test as well, it might throw an engine light or fault code on a scan.

Is it getting up to temp now? for the test? Maybe try an 87 deg stat.
Sometimes an oil change can help with emissions as well. Do you know what oil is in it?


----------



## Olie055 (Nov 23, 2007)

Thank you. Didn't have an idea there is no N112 in BAM. From what I have been reading on other forums it can affect adaptation. We will see tomorrow. Max temp was 93 but its freezing outside. Got 2 TTs so will start them in nte morning and see the differences in temp  Its same engine so good for swapping and testing parts over. Strangest thing is that original poster had nearly same results on MOT and I would really like to know where was the problem. No idea about oil I just know its 5W40. Didng get there yet but will use Motul as on any other cars 
Thank you



davebowk said:


> Pipe into the fender (catch can outlet) can go to a puck then into TIP.
> 
> N249 delete won't affect emissions unless its not done correctly and not sealed (vac or boost leak)
> Mines a BAM so don't have an N112, but as i understand it, if it's sealed then this won't affect emissions when it's at temp.
> ...


----------



## StuartDB (Feb 10, 2018)

Both these modifications are done by many people, as above SAI is only in the older narrowband APX, APY, AMU 225 engines.

You are allowed to drive a car to a garage to be fixed for an MOT, so either go to an expert eg WAK [email protected]

Or if you want to sort it yourself, you need to get a blue kkl lead and free VCDSLite otherwise you are just chucking money down the drain. You also need something to log the car, vcdslite can do some limited stuff, or android torque pro does some limited stuff or me7logger, will create the best logs for these engines.

Have you already raised some issues about your car? It sounds familiar but so many seem to sound similar.

I do wonder if your readings are very similar to the original thread owners more to do with the kit the MOT testers use, rather than co-incidentally having identical issues


----------



## Olie055 (Nov 23, 2007)

Thank you. I do have VCDS and old version of Vag-com as well  So any ideas what to look for? As I said I just bought the car with very little service history


----------



## StuartDB (Feb 10, 2018)

find the blocks for short term and long term fuel trims I think block 1 has a general look at the current, maybe 32 and 33 show the fuel trims. if you clear all faults (even if there are none) it also reset the fuel trims and they stat adapting again, this highlights potential leaks etc but see what the long term and short term are currently, then reset to see what happens.

also find the desired and actual AFR - the reason this is important is that desired should match the Map or ECU intervention and if the desired is 1 but you are actual 1.1 it means some form of extra air is being drawn in, like wise if it is 0.9 too much fuel is going in and if the desired is 0.9 and actual is 0.9 then some form of intervention is overriding the desired to produce enrichment eg knocking, coolant temp


----------



## Olie055 (Nov 23, 2007)

Changed the water temp sensor today and installed resistors in place of N112 and N249 went to MOT and passed CO 0.1


----------



## davebowk (Aug 16, 2019)

So a dodgy temp sensor was causing over fuelling. At least you know about most of the issues now. Soon be sorted.


----------



## darylw357 (May 21, 2019)

StuartDB said:


> find the blocks for short term and long term fuel trims I think block 1 has a general look at the current, maybe 32 and 33 show the fuel trims. if you clear all faults (even if there are none) it also reset the fuel trims and they stat adapting again, this highlights potential leaks etc but see what the long term and short term are currently, then reset to see what happens.
> 
> also find the desired and actual AFR - the reason this is important is that desired should match the Map or ECU intervention and if the desired is 1 but you are actual 1.1 it means some form of extra air is being drawn in, like wise if it is 0.9 too much fuel is going in and if the desired is 0.9 and actual is 0.9 then some form of intervention is overriding the desired to produce enrichment eg knocking, coolant temp


If there is a fault detected with the SAI system (and sometimes without codes) then the adaptations are disabled and lambda ignored. A healthy running engine should still be able to pass the emissions however.


----------

