Catalytic converter

[awoe771]

Hello all I'm new.
I apologize if I can't handle it well because is my first time ever.
So if I make a mistake please let me know, I only can learn from it.

thanks

I have a problem with my E280, 24V, 124, estate, L reg, 1994
She didn't pass the MOT because of emission.
The print out shows fast idle CO 0.53 it should be 0.30, lamda is ok, CO idle speed is ok, HC is ok. All figures are slightly below except from the fast idle. I have been told that the cat. is gone. My question could somebody give me an advise is that true? or is there an alternative.


many thanks

Thomas

 

[grober]

Italian Tune Up Required?

taken from another site.
INITIAL BET (basic emissions test) done first.
The BET standards are:

Fast idle 2500-3000rpm

CO no more than 0.3%

HC no more than 200 parts per million

Lambda between 0.97 and 1.03

Normal idle 450-1500rpm

CO no more than 0.5%

Basic fault finding for advanced emission test failures:

1. If a vehicle fails for high CO at idle and /or fast idle then.... if Lambda is too low, the mixture is too rich. This can be caused either by a misfire or by a faulty Lambda sensor. If it's running very rich, the 02 and HC will be higher than normal.
2. if it has a high Lambda and high 02 (0.5 to 1.5%), the "CAT" could be faulty. Before condemning it make sure its hot enough to work, the Lambda and other sensors are working OK and the exhaust downpipe hasn't got any leaks.
3. if the vehicle fails for high HC then ...if the CO passes, the vehicle is probably misfiring. Or if the CO fails and the Lambda reading is too low, the mixture is probably too rich and it may also be misfiring.
4. if the CO fails, the Lambda reading is high and the O2 reading is high (0.5 to 1.5%) the "CAT" could be faulty. Again check out the simple measures above before condemning it.
5. if the Lambda fails then...if its too high the Lambda sensor may be faulty, the mixture may be too weak or there may be a hole in the exhaust downpipe. If Lambda is too low the sensor may be faulty, the mixture may be rich or the vehicle may be misfiring.

For the reasons stated above make sure your car engine and catalytic convertor are really HOT before the car is tested. Engine temperature 80*C is normally tested by a temperature probe in the dipstick. Also make sure your ignition is in top condition- check the spark plugs are not fouled from lots of short cold journeys. Take the car for a long fast drive using lots of revs before the test. If it still fails then check the lambda sensor is giving accurate readings and replace it if in doubt--a lot cheaper than a catalytic converter.