Running the SD Super AUJP code and have a Innovate LC1? WB02. I'm pumping hte datalog into the ECM and also watching the O-meter.

I finally got the AFRTuner working and was working on the WOT AFR. Finally felt I was making progress. Was watching the O-meter today on a run and let out as it went lean...let off about 13.4 AFR. Looking at the datalog, it never gets above 12.7-12.8. I would have kept in it if it had been saying that on the O-meter.

I used the datalog, obviously, to tune the AFRTuner. I think there's about a 0.5 volt offset between the 2.

I am using this equation in my Tunerpro Aquisition file...

X * 0.058980 + 7.350000

Do I have the offset wrong or is there something messed up in my wiring? I don't think there should be as they both come off the same ground...just basically 2 outputs from the same module.

Thoughts?

 

You'll need to know what the scale is for the O-Meter to be sure they are looking for the same voltage Vs AFR reading.
The LC-1 is factory set for 0-5V = 7.35-22.** AFR (Don't remember the exact number at the moment)

IMO, the best way is to setup the WB to output so the O-Meter is correct and then adjust the parameters in the logging program to match.
I do not know what the O-meter uses for an input range,
In my case I have a ProSport gauge that is looking for a 0-5 Volt signal that will read from 10.0 to 20.0 AFR. (non-adjustable)

Since the gauge can not be changed I use this formula to make the logging correct.

Find AFR "span" which is "Max" 20.0 AFR - "Min" 10.0 AFR = 10 AFR span.
Find Volts "span" which is "Max" 5 volts - "Min" 0 volts = 5 Volts span.
The ECM is an 8 bit reading that can digitally count from 0 to 255 that equals the 0-5volt input.
10 AFR "Span" / 255 counts = 0.039216 AFR per Count
(As a reference, each count = 0.019608 Volts on the input)

Your "Base" starting point is at 10 AFR so that will be the "Offset" value.

The final conversion formula would be: X * 0.039216 + 10.0
("X" is the ECM datastream output value in counts)

Your gauge and your logging will both read the same at that point.
Be sure the WB controller is setup to output what you need for the gauge.
HTH

 

Did you set the wide band O2 to open air?

 

Even if the WB was not free air calibrated, the displays should still match.

The info on the O-Meter is as follows:


Apply the same theory as explained above,
0 - 5V = 7.4 to 19.0 AFR reading
19 - 7.4 = 11.6 AFR span
11.6 / 255 = 0.04549 AFR per count in or out of the ECM

Logging Conversion = X * 0.04549 +7.4
You must confirm the WB output is set to 0-5V = 7.4 to 19.0 AFR

Otherwise change the O-Meter to be 0 = 10 AFR and 5 V = 20 AFR to use the calculation in the post above.

 

Thanks for the feedback. I'll look into it tonight. I plugged into the LC1 when I first got it and set it up, but don't recall what I set it to. It didn't make any sense to me that it would be different than the ECM was seeing as its coming from the same output. FIgured it was 'calibration' issue.

Yes, its been free air calibrated.

Thanks!

 

OK, digging into this tonight. Found the hardware to tap into the LC1(miracle of itself)...

So the unit is set up so both outputs are the same.

0 Volts=0.5 Lambda(I calculate that as 0.5*14.7=7.35 AFR)
5 Volts=1.523 Lambda(I calculate that as 1.523*14.7=22.4 AFR)

I see that as a potential issue as the O-meter stock settings assume that 5 Volts is 19 AFR. Either Innovate Changed or I fubared it when I calibrated it originally(I have O-meter hooked to output 1 so I had to copy the Output 2 cal across at the time)

Does this sound right? So I should switch the O-meter to assume 5 Volts equals 22.4, correct?

My equation if I do the above then would be...

X*0.058973+7.35 <--I note my ECM is almost at this same equation now

0.058973 is derived from 22.4-7.35/255

If I do both of those actions, that should bring my O-meter and ECM into line with one another.

 

Yep, make them match Volts to AFR and figure the conversion.
There is a selection for Lambda or AFR in the LC-1 setup software IIRC.
On the right track.

 

Well, finally got to looking at the O-meter settings and its set up right. 22.4 for the 5V end of the range. So not sure whats going on. I did tweak the conversion factor a bit but find it hard to believe that changing out the 4-6 decimal place in a conversion will fix it...but we'll see.

Maybe I should start tweaking the bias voltage?

bi: Bias factor, default=100, range=80-120.
This is a multiplier (in %) that is applied to the incoming voltage. If your AFR somehow does not match what it should
because of impedance loading or other effects, then the value can be biased up (110 will make 2.0v show 2.2v) or down (95
will make 2.0v show 1.8v).

 

Bias should only be used if you prove that the offset is the same across the whole working range.
If both slope values are matched and you still have an offset it could be used bit I think I would try to find the reason for the shift.
Someday you may correct the ground path or something gets worse and end up with an incorect reading agin.