Failing On emissions!

timmywex

Hey,

Looking for some advice

Have a 00 citroen xsara 1.4, was up for nct a few months ago and failed! Its failed 3times more on emmisions, the c02 is too high, its been hooked up to a comp at the dealer etc etc and they said the co2 sensor might need changing, but had got a new one just about 3 weeks ago and it still failed, they said maybe a genuine cat converter but, tbh, itd cost as much as the car is worth! Ive put a spurious(advance pitstop) cat converter in it already, and reading dropped slightly, anyone have any ideas how to fix my problem by any chance?

Would some dipetane solve it maybe?

Reading is .66, down from .76, but still needs . 3 to pass!

badabinbadaboom

It a tricky one considering the cars only about 9 years old Id suggest some of that stuff(forgoten the name) for cleaning up you emissions

E92

What you need to do is drive the sh!te out of the engine, and/or drive quickly(as in over 100 km/h) for about 300 miles(preferably both), and see what difference that makes. When cars are driven gently or at low speeds(i.e. around town) for an extended period the non CO2 emissions go up dramatically because the engine gets carbon build ups. That is the most common reason behind failing emissions tests for the NCT.

Driving the sh!te out of the engine for a few hundred miles will force the engine to get rid of these carbon build ups. Don't worry about the extra stuff coming out of the exhaust pipe(provided it's not blue or black smoke of course), this means you're getting rid of the carbon build ups.

Of course it may well be a faulty O2 sensor, but this method is worth a try, and even if it doesn't make the car pass the NCT, you will have an engine that is running better and more powerful too.

Obviously if there is a warning light on you don't follow the above advice.

badabinbadaboom

+1^ if its a deisel and your really desperate you can try a wee drop of petrol too.(i mean really desperate) havent tried it myself ever but hear it works well

E92

badabinbadaboom wrote: »

if its a deisel and your really desperate you can try a wee drop of petrol too.

I wouldn't be too keen on this idea. In modern common rail diesel cars, even a few drops of petrol can make the injectors fail, meaning at least a 4 figure bill straight away. These engines have very low fuel tolerances(necessary because of the precise nature of common rail technology) and require top quality fuel for successful operation.

On older diesels without high pressure injection systems you'd get away with it though, as these designs are not anywhere near as precise and will tolerate lower quality fuel to the point they can accept up to a 5% mix of petrol depending on car.

Tech3

ya a mate of mine failed his test on emissions and was told to rev the hell out of it before the nct and passed. Not sure how much he was out by however.

badabinbadaboom

E92 wrote: »

I wouldn't be too keen on this idea. In modern common rail diesel cars, even a few drops of petrol can make the injectors fail, meaning at least a 4 figure bill straight away. These engines have very low fuel tolerances(necessary because of the precise nature of common rail technology) and require top quality fuel for successful operation.

On older diesels without high pressure injection systems you'd get away with it though, as these designs are not anywhere near as precise and will tolerate lower quality fuel to the point they can accept up to a 5% mix of petrol depending on car.

I see your logic, Im not up-to-date on modern cars myself TBH.