Free Air Calibration

[antonch]

I calibrated my WBO2 sensor using the Terminal screen while sensor is in free air (body grounded to exhaust ofcourse).

I tried a range of values from Manmttg8bcA8mcs to Manmttg8bcAFmcs and it gave me O2 % Conc range from 19.9 to 20.5.

Is 20.5 an acceptable free air calibration such that I can trust my Lambda value? I did a quick test drive and the lambda values seemed to be in reasonable range.

[rob@vems.co.uk]

Keep moving up the value until you're at 20.9 to 21.0 I've seen some sensors needing C8 to EF

Rob

[Butchs13]

So does the guage need calibrating when you first get it, or is it once the sensor gets sooted up.......

[rob@vems.co.uk]

No, the wideband guage does not need calibrating.

[jadzwin]

Hello,

I've jsut  started my car using Vems but I'm little affraid about WBO readings.
I've callibrated WBO sensor according to the instruction, but free air calibration value ranges forom 20.5% to 21.0%
(I had to set 0xce in calibration value)
(most of values are in range between 25.7-25.9). Is that behaviour ok ?
I'm afraid because my car needs to be very rich on idle to run smooth (lambda bout 0.8-0.85).

However after one day of work my car work and today I use it to drive to my work ! I'm verry happy of this device.

Thanks
Jadzwin

[rob@vems.co.uk]

I see values +/- .3 so seeing 20.5% to 21.0% is a little bit strange but if the mean average was 20.9% you will be okay, 0xCE is not a strange value.  If you by 25.7% - 25.9% you mean 20.7 to 20.9 then thats pretty good, I usually

Regardless of the calibration Lambda 1 will always be accurate, the calibration is there for values away from lambda.

Lambda on idle is always a strange one, I've seen engines that are showing Lambda 1 while unburnt fuel is spitting out of the exhaust!

Perhaps if you put some details of your install in the project page or the members page on the Wiki then we're more likely to be able suggest which direction to go.  What sort of Pulse widths are you seeing at idle and what sort of advance you're running.

[Sprocket]

How often do you need to recalibrate the WBO2 sensor with Genboard??

[rob@vems.co.uk]

You need to recalibrate only when you change sensors.

[Sprocket]

Thank you

I thought that to be so. Just some one else Arguing the toss and I didnt want to look a tit

I was linked to these as evidence that calibrating once was not sufficient. Different product I know, but it was generalised that ALL wideband sensors need this.

http://www.innovatemotorsports.com/forums/showpost.php?s=9c265144b636c27683529ce34ace81a2&p=6571&postcount=2

http://www.innovatemotorsports.com/forums/showpost.php?p=13175&postcount=1

Just another small question, if these links are not stepping on anyones toes, just trying to undestand why there is a difference of opinion. Why are they suggesting such a stringent maintenance plan just for the wideband. I have my own thoughts as to why it doesnt sound right anyway?

Rob If you feel this is wrong or out of place, you can remove it by all means


Happy new year by the way

[rob@vems.co.uk]

I wonder how you can recalibrate a dirty sensor, covered in soot from when? Half-way through a cold-start, after idling or a couple of misfires?

I dont remove threads as a matter of course.

[MWfire]

I calibrated WB senzor befor 5mouthns(8000km). Now in free air it shows 21.3% O2(average value). I will recalbirated, but is this normal for WB?
2.0 NA motor

[DevInAz]

how do you make the actual adjustments to the config to get the o2 reading to 20.9?? i must be missing a write up or something but i haven't found anything about how to make the adjustment only how to read out what the values are.

[rob@vems.co.uk]

The free air calibration method is described in the User Guide http://www.vems.hu/wiki/index.php?page=MembersPage%2FPhatBob%2FUserGuide
In the section: Calibrating the WB02 sensor

[rob@vems.co.uk]

I calibrated WB senzor befor 5mouthns(8000km). Now in free air it shows 21.3% O2(average value). I will recalbirated, but is this normal for WB?
2.0 NA motor

If the sensor is covered in exhaust residue (soot) then there is no way that you can free air calibrate it to any degree of confidence.  The soot contains unburnt hydrocarbons - as the heater gets to temperature the hydrocarbons burn which effects the nerst cell and gives a wrong reading.  It might be possible to clean the sensor with compressed air when the heater is hot but even then I wouldnt trust it.

[R-242tic]

The free air calibration method is described in the User Guide http://www.vems.hu/wiki/index.php?page=MembersPage%2FPhatBob%2FUserGuide
In the section: Calibrating the WB02 sensor

Our first task is to set VEMS to print the correct information page when requested, to do this type:

Manmlp02

Typing {mll will show the information displayed on the selected page, you will see that O2% is displayed as ??.? And that the Heater is Off.

RPM:0000 W00I00 P099
0000 00, 0000 66   
00 F1 00 00 0DF7   
AFR=?     O2%=??.?


Where do I do this things???