Tuning fuel adjusment

[Glyn22800]

Hello to all. I need your help please
I have a 2004 244 petrol, yes petrol 2litre Ducato and it has failed the test for the second time.
The handbrake I can deal with but the other is the fuel mixture. Is there any way of adjusting this or would it be down to a sensor somewhere?
I have already replaced the lamda sensor which was not only defective but was falling apart. I have cleaned the throttle body and it runs very well so I am surprised it failed on the fuel mix.
I would be obliged for any help as we still had carburettors when I was a mechanic and am a bit lost with all this technology.

 

[varesecrazy]

Hi.

Give us the numbers..

Then we can give an indication of what to look at.

Plugs and airfilter good?

How old is the oil??

Getting properly HOT.. basics.. but crucial for emissions.


Idea.

Not drawing air through exhaust.. ?

Charlie

 

[Glyn22800]

Hi Charlie,
Thanks for replying.
I'm not sure what the numbers mean so I'll write them as they are on the failure ticket.
CO idle (0.3) ;0.14CO accelerated idle (0.2) ; lamda (0.97 to1.03 ; 1.010
With the Lamda sensor reading being so high I think you may be right about it sucking in air to the exhaust. I will check it out this morning and let you know what I find.

Many thanks

 

[Anthony489]

HiGlyn. Your vehicle will have an exhaust Catalyst, and the enginemanagement uses the Lambda sensor to monitor and continuously adjust theAir/Fuel ratio. A Lambda reading of 1.000 indicates that exactly theright amount of Air has been used to completely burn all the Fuel. Toolittle air will cause a rise in partially burnt Fuel, which produces CarbonMonoxide (CO) in the exhaust, and unburnt Fuel, i.e. Hydrocarbons. Amisfire due to an ignition fault, worn plugs etc will have the same effect.

The MOTtest limits are: Carbon Monoxide (CO) at Idle, Less than 0.3percent. CO at Fast idle, Less than 0.2 percent. Unburnt Fuel(Hydrocarbons), Less than 200 parts per million (PPM). Air/Fuel Ratio(Lambda), Between 0.97 and 1.03.

I can'tcompletely make sense of the readings you have supplied from the failticket. It would seem to me that a Lambda reading of 1.01 is well withinlimits, and in any case a reading greater than 1 indicates MORE air thanrequired. If the vehicle has been run for any length of time with afailed Lambda sensor, it is of course possible that the Catalyst has beendamaged and is no longer fully effective.

My Fatheronce had his car failed for emissions, despite having passed every yearpreviously. It turned out that the testing station equipment was faultyor hadn't been calibrated properly. They had such blind faith in thereadings that no-one had questioned why ALL the cars they tested that morninghad failed ! He eventually went to another test centre where it passedwith no problem, and got a refund from the first guys.

 

[Glyn22800]

Thanks for you input Anthony,
I do hope it's not the cat as I had to replace it when the vehicle was just out of guarantee. Price here in France? 1,030 euros!