Technical Brava wont pass emissions (NCT)

[punto16v]

My uncle has a 00 brava 1.2 for the last 8 years and in that time the car never had problems passing the emissions test (NCT) it keeps failing on the co low idle is reading .67 where as .50 is the limit lambda is reading 1.00 which indicates that it is working .

So far we checked the exhaust for leaks air intake for leaks changed the plugs and cat but still wont pass we plugged the diagnostics into it but no codes came up .

Any ideas would be much appreciated before i pull my hair out over it :bang:

 

[Ziggy122]

The max the car is allowed is .50 CO on a low idle
You've got .67

When your getting the lamba to read, the voltages should be moving up and down from 0.01 to 1v some are .1 to .9

Showing the car is seeing and altering the fuel mixture level

If the voltage is simply Stuck at 1v
it'll be running richer then it should

im assuming been a 2000 its a not got a pre and post cat

It could be a Dead lamba to me - but could also be a sensor on the intake at fault

This can help as well
http://www.picoauto.com/applications/lambda-sensor.html

Also - are you giving the car stupidly hot to them? As hotter means its clearing out
So make sure you use posh petrol and a good lead boot on the pedal to get it warm and blow the cobwebs out

Ziggy

 

[punto16v]

We can check the voltage of the lambda with the diagnostics and it is fluctuating as it should .

You can drive it like you stole it and the emissons are still the same as if driven sensibly its averaging about 45mpg around local that is what is throwing me as i would of thought that it would be heavy on petrol .

 

[dirtyhands]

you also have not said if you have changed your oil and filter as it could be contaminated bringing your readings up,we would also throw in a can of power kleen into a 1/4 tank as that will clear the crap out.

 

[punto16v]

The oil and filter was always changed every 6k there is nearly 180k miles up on it but it is absolutely driving perfect not burning oil or loosing water . The oil doesnt even go black before it gets changed .

Today alone we have cleaned throttle body ,map sensor , we added some dipetane to the fuel .
Last week we changed the plugs ,checked the exhaust for leaks ,fuel filter and still no change whatsoever .:bang:

 

[Oversteer]

I had a similar problem last week when I took my girlfriends Bravo 1.2 for its MOT. The CO and hydrocarbon levels were way over the allowable limits and so the car received a fail. The MOT tester then sat revving the car up to around 5000 revs per minute for a few minutes then put the car back on the emmissions tester and hey presto! the levels were totally different and well within the acceptable levels and the car passed, MOT man explained that when a catalyitic converter gets old it takes time to work efficiently, this and the fact the car is only ever driven around town on short journeys clogs the cat up leaving it unable to do its job properly. So in a nutshell, before an MOT (and as per the suggestions made above) I would suggest the following:

new engine oil and filter
new air filter
put some 'Cataclean' in the fuel tank
take it for a 20 mile run down the Motorway at 70-80 MPH (Italian tune-up!)just before the MOT test.

 

[paultaylor6003]

I'd prob say the same take it for a wee back road thrash then take it back over I done that with a few of mine and they fall within limits and had to do it with my 1.6 16 to get her to gd limits, and I used power clean and super credit card rape unleaded, good luck mate.