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[hol666]

Hi, just failed the mot for the first time with the 2.0 16v, excessive emissions was the main one, co2 over .700 when should be under .300???  :-?

I have, for the first time, cleaned up the throttle body which was totally black with crud!  Now, after thorough re-assembly, you know, when you wonder why the eml light is on only to realise you failed to connect up the air flow meter and the 'other' one .

I had a tick-over of 2500rpm, now it is @800rpm, is there any way to adjust the tps to lower it again?  I removed it to clean up the throttle body and did move it to lower the rpm initially.  I'm hoping that cleaning up the tb with help with the emissions too?

[VX1]

The throttle position sensor cannot be adjusted, the idle can only be adjusted by Tech1 for 94 upto 97 and Tech2 for 97 onwards. If your emmisions are high that points to the lambda sensor, this will need to be replaced, costly from dealers but you can get the right universal one which you will be better off getting a direct replacement which means direct fit. Once new lambda sensor fitted your emmisions will come down to what they should be. Have you cleaned the breathers or replaced them? This will also help your idle as well, also have you cleaned the IACV?

Cheers Paul  

[JamesV6CDX]

If Emissions are too high:

Clean up throttle body, IC Valve, and breathers until squeaky clean.

I once looked at a V6 with high emissions - valve timing was all over the place. Correcting this fixed it. Presume yours is ok?

To be honest, if the Hydrocarbons were high, I would suspect engine/sensor related issues, but if the CO is high, maybe the cat is tired?

700 is a high reading! Does the car use any oil?

[JamesV6CDX]

If your emmisions are high that points to the lambda sensor

Once new lambda sensor fitted your emmisions will come down to what they should be.

Hold the horses... there can be other causes of high emissions. Investigate thoroughly, before "trial and error" by replacing parts you're not sure are the root cause.

[hol666]

  thanks guys for that.  OK the throttle body has been totally cleaned up, it was BLACK and thick, took a whole can of carb cleaner to do it.

I have also cleaned up the breathers and I do mean all of them!  

Plus, the idle has been adjusted via the throttle position sensor, the screw holes are slightly bigger the the screws, hence some small adjustment is available.  

The lambda sensor and cat are less than 6 months old and since I have no eml on which I assume would light if the lambda was faulty, I'd guess its ok.

The car is running much sweeter now after the tweaking with the help of a friend.  

Incidently, if anyone in the wiltshire area, near to Devizes, need tracking done, Bathwick Tyres do full geometry tracking for £55 inc vat.

I forgot to add this, we poured some neat redex into each pot and refitted the old plugs and then turned the engine over, it actually tried to fire up??
apparently this meant the engine was pretty coked up, after leaving this for an hour or so, it didn't do it again, so hoping this is now clean

Plus to cap it all off, the damn handbrake cable snapped today   having a bad car week!

[hol666]

Right, just been for a retest after spending the weekend renewing the handbrake cable, it snapped!! and handbrake shoes, they fell apart!!!   And struggling to get that sorted, failed again on emissions.  Chatting with the tester, he was confident that the lambda was switching but was dubious about the cat being efficient.  Toddled off to ATS who fitted the cat back in March, a helpful bloke there rang a friendly mechanic who pretty much diagnosed over the phone that the cat was dead if the CO was that high ( 0.700 ++++ ), tomorrow they fit another, the 3rd as it happens!! So hopefully, this'll solve the problem, bloody well hope so anyway

[hol666]

  OK, today, took the car to ats and left it with them for the cat replacement, they then took it next door to another MOT station to get the emissions double checked before they did anything, as I'd expected.
This MOT place PASSED the car on its emissions!!!  Apparently, this guy ran the car for 5 minutes, revving the motor upto 3000rpm to ensure the car was upto temperature.  The original MOT place, MOTest in Swindon, only seem to let the motor tick over which by all accounts isn't enough?

Anyway, I took the car back to motest, along with the printout from the other place and showed them, 2 hours later, I had a phone call saying my car was ready and had passed.    I walked over to pick it up, when I turned on the ignition, the temp guage shot up to over 90, they must have given it some stick!  

Still, thats done now and another 12 months until the next round of fun begins again.  Thanks for all the suggestions on what the cause was, no-one guessed it was the mot station and not the car though!!!    

[Taxi_Driver]

OK, today, took the car to ats and left it with them for the cat replacement, they then took it next door to another MOT station to get the emissions double checked before they did anything, as I'd expected.
This MOT place PASSED the car on its emissions!!!  Apparently, this guy ran the car for 5 minutes, revving the motor upto 3000rpm to ensure the car was upto temperature.  The original MOT place, MOTest in Swindon, only seem to let the motor tick over which by all accounts isn't enough?

Anyway, I took the car back to motest, along with the printout from the other place and showed them, 2 hours later, I had a phone call saying my car was ready and had passed.    I walked over to pick it up, when I turned on the ignition, the temp guage shot up to over 90, they must have given it some stick!  

Still, thats done now and another 12 months until the next round of fun begins again.  Thanks for all the suggestions on what the cause was, no-one guessed it was the mot station and not the car though!!!    

Hope you got a led keyring torch off them  

Glad its sorted now tho  

I took my veccyc there a few weeks ago......i thought it odd they never asked if it was running on lpg or petrol when they did the emissions......as other mot stations have always asked as apparently they lower the max figure if on lpg......but hey, they passed it so i wasnt going to complain  

[hol666]

  yeah, I did, the guy before me was really upset they didn't offer him one!  He kept mentioning the letter that stated 'free led keyring', I had trouble keeping a straight face!  
Thanks for that, all seems ok now, should do after the amount I've spent!