O2 sensor signal

[gistvan]

Hi!

Does this graph, and csv file imply, that i have a broken after-cat o2 sensor?
the idle-running rpm is fluctuating all the time, and i dont know, why.

thanks!

[mattydr67]

What I saw in you CSV its that your fuel mixture work "rich"
It mus have a fluctiation betaween 0.2V (lean) and 0.8V (rich) to be in normal parameters.
That its for pre-cat O2 sensor.
I think that your pre-cat O2 sensor is broken, not after-cat O2 sensor.
The after-cat O2 sensor work well but it show you that your emisions are not in the parameters. It must be near 0.45V and must be pretty constant.
That's because your pre-cat O2 is out of range, working rich.
For your idle can be a cause but not the only one.

[Deckchair5]

Before you worry to much it looks like there is a bug in the program. rpms are in millions so they need 10 to minus 3 multiplier and for O2 sensors, whenever there are just two digits in the readout the value needs to be mulitplied by 10 and so the data multiplier formula seems to have a problem

[yani]

Before you worry to much it looks like there is a bug in the program. rpms are in millions so they need 10 to minus 3 multiplier and for O2 sensors, whenever there are just two digits in the readout the value needs to be mulitplied by 10 and so the data multiplier formula seems to have a problem

RPMs are not in millions.
He has used , (comma) as a decimal separator in the CSV file, and RPMs are correct.

Yani

[Deckchair5]

Hi Yani
Ah yes i see the effect of the comma separator now

Can you see what's happening with the O2 sensor figure readouts as that appears on the program graphs and the csv

[hanzs]

My opinion is, that both O2 sensors are ok. Both shows values between 0,05-0,8V and this is ok.
RPM changing on idle is probably due the mess in throttle valve (very common problem).
My picture of o2 sensors: "volnobeh"=idle , "proslapavani plynu"=playing with gas pedal (rpm changing).
http://merkur_sound.sweb.cz//lambdy.jpg

[Deckchair5]

Hi Yani
Is there any way you can change the graphical display as it's very difficult to read in the present colours, text size, trace width etc. It's easier to look at the csv data output and that's not the way it should be. The graphs should make it clearer to compare the raw data

Here's a Gendan diagnostics display and it's very easy to see and compare what's happening

[yani]

Hi Yani
Is there any way you can change the graphical display as it's very difficult to read in the present colours, text size, trace width etc. It's easier to look at the csv data output and that's not the way it should be. The graphs should make it clearer to comapre the data

Here's a Gendan diagnostics display and it's very easy to see what's happening

You can go to Settings and change colors, font sizes and line thickness the way you want.

Yani

[Deckchair5]

Yes what I mean is the program default settings as people are posting up their graphs in the default settings and they're almost impossible to see
Look at the graph at the top of the page

The more a program works well straight out of the box the more impressive it is

In use in the car then it's usually bright conditions so a dark colour trace on a dark background isn't recommended