MOT Emissions Fail HELP?!?!?!

[Ad172UK]

My 172 has failed its MOT today.

Failed on a couple of minor things and then the emissions. Values are quite high and so could do with some advice if possible?

Fast Idle Test :

CO - 9.42% Vol
HC - 953 ppm
Lambda - 0.73

2nd Fast Idle Test

CO - 11.66% Vol
HC - 1865 ppm
Lambda - 0.65

Natural Idle

CO - 8.53% Vol

Will update this as and when i find out more as i will be plugging the RS Tuner is and clearing codes before going for a drive and reporting back new codes.

Just for reference the car had just had the decat swapped off for the MOT. The car is running 421s which are currently unmapped. I have a feeling its definitely the mapping that needs doing to sort it out but would like it confirmed as i dont really have the money for mapping until 28th and thats after my 10 day retest.

Thanks

 

[TheEvilGiraffe]

HCs high much ? Running RIIIIIIIIIIIIICH. Infact, is your decimal place correct ? How can they be more than 100% ?? Or is that 1865% of the limit !?

Lamda fubar'd ?

 

[Bassplayer]

HCs high much ? Running RIIIIIIIIIIIIICH. Infact, is your decimal place correct ? How can they be more than 100% ?? Or is that 1865% of the limit !?

Lamda fubar'd ?

D'OH!

HC reading are ppm not % that is why they are so high.
Those readings are horrendous. You are damaging the cat driving like that. Do a diagnosis, and hope it's a lambda sensor.

 

[Ad172UK]

Here we are

To me it looks like rear Lambda as its voltage doesn't adjust with the revs like the front lambda does. Does this sound right?

 

[gti6steve]

You must be always at the petrol station that's is rich as hell lambda sensor me thinks mate

 

[Ad172UK]

I am there regularly mate - lol

It still shows 25+mpg on the dash though :S

RS Tuner shows rear O2 sensor so think it may be getting changed.

Before that though may take it out for a long drive and then have it emission tested by a mate whos an MOT tester.

Oil engine temp on todays test was 60c, not sure how warm that is :S

 

[hipwell]

Rear 02 sensor does not affect fueling.

 

[Ad172UK]

Rear 02 sensor does not affect fueling.

Bad times

Any ideas?

 

[Sean6545]

Front o2 sensor by the looks of the graph bud. Should be a healthy "up and down" signal varying from 150mv to 800mv aprox.

I take it it was hot when you did those graphs?

 

[gti6steve]

No way the rear lambda sensor that don't control fueling change the front one and hope for the best had my mates one in my place and it was doing the sane but not as bad and it didn't show no code for the lambda sensor but it was your not running a decat by any chance are you seen this before

 

[Ad172UK]

Front o2 sensor by the looks of the graph bud. Should be a healthy "up and down" signal varying from 150mv to 800mv aprox.

I take it it was hot when you did those graphs?

It had been run home from work, about half hours drive and left to sit for about 5 mins while i ran up for the rs tuner and then started again. Gotta go out for a quick spin in a min so when its hot i'll do another reading.

No way the rear lambda sensor that don't control fueling change the front one and hope for the best had my mates one in my place and it was doing the sane but not as bad and it didn't show no code for the lambda sensor but it was your not running a decat by any chance are you seen this before

I may put the rear one in the front hole then, or i could stop being a tight arse and buy a new one lmao

 

[Ad172UK]

Cleared the faults, took it for a drive and the O2 sensor error hasn't reappeared.

Ive found a split in my silicone elbow, could it be this?

Also i've had MAF sensor fault codes appear in the past but they're not present at the moment.

 

[Fred@BTM]

they don't have a MAF

i still think its either CTS or Lambda

 

[Ad172UK]

Fred shall I data log the CTS and upload it?

I have a log of the O2 sensors but Photobucket is playing up so cant upload it

Ideally I need to get the cheapest sensor done and then have an emissions test done somewhere other than the MOT garage so I don't waste my free retest.

Would it be MAP sensor faults i've had before then? lol

 

[Ad172UK]

 

[Ad172UK]

Also it does struggle to start a little bit, It used to just turn over straight away. Now its like its struggling to start breathing

I hate MOTs

 

[Ad172UK]

Anyone else suggest anything?

Lambda's seem to be functioning properly on RS Tuner :S

 

[Fred@BTM]

maybe it does need a map afterall?

you checked the CTS yet?

 

[Ad172UK]

maybe it does need a map afterall?

you checked the CTS yet?

Nah not yet, but the temp display seems to sit dead centre time after time day after day,same since the day i bought it.

Need to register then and get in touch with Paul

 

[hipwell]

so even from cold your temp needle sits center?

just a teeny bit above center is good for a phase 2 when hot, but if if its half way from cold them that suggests dodgy cts

 

[Fred@BTM]

^what he said

 

[Ad172UK]

Nah. Takes some time to come up to center(ish)

Ive seen another RS Tuner log of a front O2 sensor and his waves are alot taller than mine so i think its buggered.

Im not sure if the CTS is faulty, But it has done 80k miles so why not.

Fred so you have to drain the coolant to change the CTS?? :S

EDIT : This thread, when compared to mine his sensor does alot more voltage changing.

 

[Mitchell999]

Mine was the same.. I went to nz for a year and car wasn't used. Lambada sensor had a cleaning with contact spray and was okay after that