lew0.5

grrrrrrrrr so went for the mot, we have failed the emmisions test on the lamda sensor supposed be between 0.97-1.03 im runing at 1.23 apparently.
drop link bushes and daft fecking number plate bumbs

pain in the bum. ive been told i could replace the sensor but theres two i think and the chap at the mot place said there bout £70 each and if would not be a dead cert that would be it sorted.

grrrrrr

m@t STImulation

iTrader: (3)

not good i was wondering if turning the boos down on the car would make it pass but at idle they are not on boost

chris_bobuk

iTrader: (1)

Is it sports cat or standard?

lew0.5

standard except a big bore back box but even then emmisions have already passed thru the cats

joz8968

iTrader: (13)

* Knackered Lambda sensor/s (most probable)

* Knackered HT lead/s (possibly)
* Knackered plug/s (possibly)
* Clogged air filter (possibly)
* Knackered coilpack (possibly)

* Out of spec MAF (unlikely)
* Knackered cat/s (unlikely)

* Carboned/blocked up engine (unlikely - hopefully!)


As you can see, it can be a bit of a lottery in replacing the correct item/spending as little as poss first time round.

ulsterscooby

Theres plenty of additives on the market that will reduce your emissions

joz8968

iTrader: (13)

Do they actually work?

Is there any paricular brand that does successfully get the emissions right down, do you know?

34srm

its most likely to be first lambda , the one before the cat

lew0.5

plugs have just been done recently

il try the lambda behind the cat but i have a pal whose knows a pal who will make sure it goes thru

34srm

youve got a pal who knows a pal whos pals pal knows someone whos pal is an mot tester yes we are all thinking the same recipe for disaster why not just get it sorted may even gain a few mpgs thats gotta be good on a scoob

The rookie

iTrader: (1)

High lambda can be caused by an exhaust leak......seen it often enough, all your joints good?

Jozz's list is hogwash I'm afraid, other than a MAF or sensor issue, none of those will change Lambda (mixture), in fact any misfire adds oxygen to the engine out exhaust gasses which when conpensated for by the standard Oxygen sensor means it would run RICH not lean!

Oxygen sensor (it can't sense Lambda its inferred from the Oxygen reading) failure usually sends it rich, and if its genuinly running that lean (AFR 18:1) it would run like a bag of bones, so I suspect the engine is running at Lambda1 and you have an exhaust leak.

Note for doubters, Lambda is calculated using CO,CO2,HC and O2 measurements (MOT stations have to use the more common Spindt calculation), as the pressure pulses go down the exhaust you hear it blow gas out, but the vacuum behind each pulse also sucks air (inc Oxygen) in and this is read and leans off the Lambda calc at the tailpipe.

Simon

joz8968

iTrader: (13)

My (very) bad - I overlooked the Lambda of 1.23 (i.e. way lean) - sorry about that.

I fell into the 'trap' that, more often than not, most MOT emissions failures are because of too high CO and assumed the same when I read "...failed the emissions test..."

I really should learn to take on board what's actually been written...

The rookie

iTrader: (1)

No worries mate, we've all done that at some time or another!

Simon

r1c

iTrader: (9)

air leak or sensor probs, like said above, someone knows there stuff

lew0.5

cool guys il give the exhaust pipes a good check over, the car seems to be runing ace though, sometimes you notice a dip in performance with a leaky exhaust too. will keep everyone updated on the progress..

lew0.5

so here is the latest on the emissions saga, if anyone still cares. i took the car back to the chap i bought it off cos hes a pal and he swore if it didnt go throught the mot he would sort it himself. so he's taken it to another mot testing station, now I was unedr the impression that he knew the pal it was gonna be a bit dodgy but a pass none the less. couldnt be more wrong, he put it in as usual they did the mot and passed the emissions test with flying colours had the bushes and bulbs done.

Just goes to show you. Raging mad with that other garage, there gear must be faulty or they are ripping people off let right and centre.

So that me got my 1st scoob on the road all legal. F*cking loving the drive and the power from the wrx is amazing would probably cack myself in the sti then.

Cheers for all the help and advice guys, found a good forum!

joz8968

iTrader: (13)

Yep! Some MOT centres are as **** as hell and do it totally by the book to the letter, to try and get another paid test out of you, etc...

I took my old Clio 16V into a centre and it failed on handbrake performance (plus pads were low). Got it all fixed perfectly - and for a tidy sum I might add - but the bloke was unrepentent on the retest and claimed that the handbrake was slightly out of spec and had no hesitation in failing it again, despite me showing him the receipt for all the work carried out by a reputable local garage, etc.!!! What a fcukhead!

Ho hum, you live and learn.

Glad you're all sorted... and nice to know it all passed doing it 'by the book' too. Makes you feel good, don't it?

lew0.5

yeah man well chuffed