How to set up EIO when you have a voltage offset

[S2H]

So you have hooked up yor Wideband or MAP sensor to your EIO...
and you notice that the 2 dont report the same value...
as an example I'll use a wideband that has a 0v~5v rane and a 10~18 AFR range

Wideband reports 3.0v
EIO reports 2.7v

so you have an offset of .3 volts (WB-EIO)(3.0-2.7)

You will need to make a Custom PID for the EIO to be accurate

volts / (voltage range/Device range) + (Minimum value of device range)

Volts/ (5/8) + 10
5/8= .625
Volts/ .625 + 10+offset in value of device\

Edit: fixed this part of the equation below
.3/.625 =0.48

so in our example
Volts / .625 + 10.48


you can also correct for AFR by looking at it in Free air...if your Free air calibration is supposed to be 18AFR and you see 17.52 AFR then you need to shift it to match teh 18 specified by the device(again I'm using the math examples above)

[12secSS]

Question:

How would you verify the AFR -> Voltage output for the specific range ... or does it not matter? I want to verify that this "equation" will result in true numbers and not just shift the scale over. Any idea on how we could verify the results without blowing something up.

[MeentSS02]

Good luck with that one...the voltage offset on mine isn't the same throughout the 0-5V range. It is fairly linear, but not exactly. I just made a new linear graph using some data points and Excel.

[12secSS]

Can I see you excel file as a reference? How did you go about it. I have seen some being off, but I would like to verify their results first.

[MeentSS02]

I'll have to round it up...I'm at work right now, so it might take me a while. All I did was told the LC-1 to output a set voltage, and recorded an average of the raw voltage over a few data points. I made one column of the voltage recorded, and another column of the AFR that should be assigned to it (which is just what the LC-1 would have been putting out at its set output voltage based off of my 0-5V = 11-17 AFR values).

[SideStep]

I know how to log the Raw voltage output of the EIO but how do I log the WB's voltage output??? My WBC control-box has a direct usb connection to my PC but that is for the DJ WBC software (which I never use)....

[S2H]

I know how to log the Raw voltage output of the EIO but how do I log the WB's voltage output??? My WBC control-box has a direct usb connection to my PC but that is for the DJ WBC software (which I never use)....

use a voltmeter

[MeentSS02]

Hmmmmmmmmmm...I just set my LC-1 to output 0.5V, 1.0V, etc for all AFR ranges (one voltage per one data point of course). I just trusted it to do what was right...that doesn't mean it was though. I guess the only way to know for sure would be to whip out a multi-meter and go from there...

My voltage offset I was seeing based on the method I used only resulted in about a .1 AFR error, which isn't too bad in my mind (the EIO thought it was leaner than it actually was, resulting in a tune that made my car a little more on the rich side).

I guess it depends on where you have everything grounded...my LC-1, XD-1, and EIO grounds all share the same ground wire going to one bolt threaded in to the front of the passenger side head, and the LC-1 heater ground goes on a completely separate wire, to another bolt on the same side of the head.

[SideStep]

use a voltmeter

I can do that... going to take a co-pilot though....

[MeentSS02]

If you can command the DynoJet WBC to output a fixed voltage like you can the LC-1, you should be able to do it while it is sitting there idling.

[S2H]

If you can command the DynoJet WBC to output a fixed voltage like you can the LC-1, you should be able to do it while it is sitting there idling.

thats what I suggest
set it to a fixed voltage....say something that would be the equivelant of stoich..so its the most accurate there...
then just measure voltage with voltmeter to see what you get and check it on EIO as well
I just use a volt meter and touch the leads of the EIO while its all connected like I'm gonna use it...then youjust change the formula till it matches...or whatever you feel is "close enough"

and even if you cant change it or dont know how....
just do it free air where you know what it should read

[SideStep]

DAMN good ideas... I am not sure the WBC will let you do it though. I may have to call DynoJet...

BTW, what is meant by "free air"

Thanks for the replies...

[S2H]

Free Air - not in an exhaust pipe...not near any exhaust fumes...just out in the open air flapping with the wind...no chance to get anything except for its Most lean value

[MeentSS02]

DAMN good ideas... I am not sure the WBC will let you do it though. I may have to call DynoJet...

BTW, what is meant by "free air"

Thanks for the replies...

Take it out of its bung, seal the bung, and let the car run while it is outside the exhaust stream. Then it'll be in an environment where the oxygen content is a known value...

[MeentSS02]

Free Air - not in an exhaust pipe...not near any exhaust fumes...just out in the open air flapping with the wind...no chance to get anything except for its Most lean value

Damn you and your quick response

[S2H]

Take it out of its bung, seal the bung, and let the car run while it is outside the exhaust stream. Then it'll be in an environment where the oxygen content is a known value...

dont even have the car running..exhaust fumes if strong enough can make teh reading not correct.

[SideStep]

SWEET, you dudes rock...

[MeentSS02]

But wouldn't the system voltage of the car have an affect on everything else (since the voltage is being supplied via the alternator instead of the battery)?

I was able to actually have the wideband sensor with me in the cabin with the door open...not sure if any fumes were in there or not. Good point though.

[S2H]

Damn you and your quick response

yeah..I'm quick draw

[S2H]

But wouldn't the system voltage of the car have an affect on everything else (since the voltage is being supplied via the alternator instead of the battery)?

I was able to actually have the wideband sensor with me in the cabin with the door open...not sure if any fumes were in there or not. Good point though.

not on my car it didnt