Disable lambda post cat please.

[morgano]

Hello.

If someone can disable the lambda sensor in this file i would be very greatful. File is read with Kess v2. It is my work mate car, and it consumes 9L every 100Km, so we want to discard lambda. It is Xsara Picasso 1.6 16V petrol, ME7.4.5

Thanks in advance.

[morgano]

Please... these car has two lambda probes, we would like to test disabling second one. We have exchanged sparks, clean the butterfly, etc, we managed to get stable idle but the MPG is a scandal, we suspect one of the probes is out of tune even still into specs and it makes the car use too much fuel. No DTCs stored, other than the radio tells antenna signal is poor :-?? Car makes no more than 550km with a full tank.

Please help us with this.

[morgano]

Thanks for the file, you know who you are ;)

[oldford]

Bad mileage is almost certainly not caused by the post cat Oxygen sensor.
You don't give a model year, but with these older cars the post cat Oxygen sensor usually only checks the cat.
Driving conditions (city or highway) have a greater impact.
This car is specified for 9.3l/100km when driving in the city.

If it is really running to rich, a simple exhaust gas test would confirm that.

[morgano]

Thanks for your comments, bad mileage is not only in city driving. On highway maybe it does 600km, with luck....

We know there is an issue with car, just not found it yet. Disabling second lambda was with the intention to be able to swap first and second to make tests without having to spend without reason on new lambdas if not really needed.

If we would find the lambdas are the reason, would replace them an use original sw. But spend on new lambdas without certainly know they are the problem... Was not our idea :)

If i remember well this car is 2005 year. 1.6 16v 110hp. Any other idea what can be causing the fuel consumption to be so big will be welcomed.

Thanks for your answer ;)


Regards,

[oldford]

Any competent mechanic with the right equipment could tell you if the Oxygen sensors are failing or not.
Just by using a scanner and reading live data, combined with an exhaust gas tester. It's not rocket science.
One of the tell signs of mixture problems are the fuel trims (both Short and Long term).
Any idea of their value when the engine is warm and idling? Or when it is revved to say 3000 rpm?

Other reasons could be sticking brakes (check for hot wheels), mechanical engine failure (compression, valves, timing belt), air leaks (both intake and exhaust), etc.

If the two oxygen sensors are really the same just swap them. Then leave the post cat sensor disconnected.
That will give you some DTC's, but after reconnecting the post cat sensors they will disappear.

[morgano]

Thanks once more for your comments, we don't have exhaust gas tester equipment :( So we will try to look for the trim values you talk about using my lexia.

Just to say the car has all it's power, it can pull a caravan uphill no prob when revved, but it is very very lazy giving the power.

You could stick your foot on the gas pedal and it takes lot of time untill you feel the power, even if you press and lift, press and lift quickly pedal, you feel no change in the car acceleration, absolutely no jerking at all, same as if you haven't done it, seems it has a biiiiggg lag answering pedal requests. You floor the pedal and takes huge time in developing. Don't know if this can be some kind of clue too.

Thanks again for your time ;)