Wiring Wideband O2 Sensors

mike_sno

Goblin Guru
I wired my wideband O2 Sensor as well to the AC Pressure sensor. I found this video to be very helpful to get maximum accuracy of the analog signals.

Unfortunately no matter what I try, VCM Scanner does not read my Serial input.
 

Ross

Goblin Guru
What signal is it that you are trying to get in on the serial input? Since you put your wideband on your AC Pressure sensor, that signal will be on the canbus... just need to find the AC pressure sensor, and apply some math to it. I have seen that formula here on the forum...
 

mike_sno

Goblin Guru
I have the Innovative LC-2 Wideband controller, connected via Serial to my laptop. Was logging a a drive with the innovative software. In HP Tuners I have added the serial channel for the Innovative LC-2, but it disappears as soon as I start recording. I tried all kind of things I have read in HP Tuners forum and saw on youtube, but can't make it to record directly in HP Tuners.

The AC pressure sensor is a workaround. I was hoping to eliminate the Digital/Analog conversion of the LC-2 followed by a Analog/Digital conversion by the ECU.

The math and calibration of the signals is not the problem.
 

Ross

Goblin Guru
You can see the wideband data with the innovate software, but not on HP Tuners?
A Tripp Lite USB to Serial Converter helped me get the O2 data. I had a cheap serial to USB converter that was causing me data issues. Still, sometimes I have to reboot the laptop to get Windows to recognize the USB converter.
Here is my setup.
 

mike_sno

Goblin Guru
You can see the wideband data with the innovate software, but not on HP Tuners?
A Tripp Lite USB to Serial Converter helped me get the O2 data. I had a cheap serial to USB converter that was causing me data issues. Still, sometimes I have to reboot the laptop to get Windows to recognize the USB converter.
Here is my setup.
That's correct. I can see the Wideband in the innovate Software but not on HP Tuners.

I used a good USB Serial converter. That thing was the only one which worked on my milling machine. The connection to the innovate Software is stable. https://amzn.to/4bFEJVs (Affiliate Link)
 

mike_sno

Goblin Guru
Here is the reason why I want to read the Signal directly from the Serial port instead of going over an analog input. And a way to get the most accuracy out of the analog output.

Analog Input Calibration:
  1. Set up VCM Scanner to simply log the AC Pressure Voltage. I used 5 decimal cells.
  2. Program the Wideband controller to send a flat voltage. E.g. 3V
    45513
  3. Run VCM Scanner for like 3 or 4 minutes. Which gives you over 1000 counts in the cell. The Average voltage should be stable.
  4. Note the commanded and measured minimum, -maximum and -average voltage.
  5. Repeat Step 2 -4 with different Voltage settings. I suggest using at least something like 1 V and 4V. If you want to go crazy: I did a complete set from 1V to 4.5V in 0.5V steps and filled it in the table below.
    45512
  6. Now I saw that the Analog Input gets really high in the tolerance below 2V. That being said, I went ahead and used the Range 2-4.5V from now going forward.
  7. A bit of simple linear algebra and the incline and zero point were located. See attached Excel if you want to know more.
  8. Now I set up a userdefined math sensor to correct the Voltage reading to match what the Wideband controller spit out. The formula for correcting my Voltage readings is [7101.10] * 0.990972 - 0.0842
    45514
  9. With this user parameter I tested the reading again. Programm the wideband sensor to whatever Voltage in the range you selected. For me it worked out. HP Tuners has now a corrected Voltage reading.
  10. Depending on your preference you can now select a AFT or Lamda range and continue with the math to calculate the desired value.
I did not test if the reading is much different between running on battery or when the engine is running. I put a power supply to simulate a running engine and could not see a difference in the reading.
 

Attachments

Anks329

Well-Known Member
I’ve got my wideband setup in HP Tuners through the AC pressure signal. I’m trying to use Torque Pro app on my tablet to see the AFR, but to create and pull a custom PID, I need a hex code. I tried a simple conversion of 7101 to hex, but that’s not working. Anyone have any suggestions on how to connect this up?
 

mike_sno

Goblin Guru
Unfortunately no matter what I try, VCM Scanner does not read my Serial input.
Well, I found the solution. VCM Scanner is only looking for the auxiliary serial devices at Com Port 1. I had com port 4 as my USB to Serial adapter. Once I changed it, it works. Exited to get to the next test drive and make a log with max accuracy.
 

mike_sno

Goblin Guru
It seems like Com Port 1 is not the solution. VCM Scanner and external serial devices maintain to be a pain in the .... . It is very unreliable when VCM Scanner will pick up the Serial input and when not. I had to completely change the com port of the Serial to USB adapter AND the HP Tuner device to make it work again... several restarts and so on included. However I was able to get a comparison between the AC AFR Reading and the Serial AFR reading.

The picture below show that the Serial Reading is a bit faster and always a bit richer. I calculated manually a maximum error of around 5% between the AC input and Serial Input. Not in the graph, bit the Narrowband O2 Sensor is even faster than the Serial Innovative Sensor.

I had an error in the Formula, that's why AFR ER is not calculating correctly.

2024-06-09 13_44_03-VCM Scanner_ 2007 Chevrolet Cobalt LEV 4 – Sport Coupe, 2.0 L, L4,.png
 

mike_sno

Goblin Guru
Spend 3h getting the Wideband back into VCM Scanner. It is so frustrating. Could not get it back and working. Guess I will just be 5% off.
 

Rauq

Goblin Guru
You can set your tune up to minimize adders like piston protection and cat over-temp and log fuel trims and compare to the wideband. I will always trust the narrowband O2 sensors when running closed loop over a wideband, but with enough data and some Excel math, you should be able to verify how close your wideband is at stoich. And if 14.7 is really 14.7, then to me the scaling is relatively trivial, whether 13.0 is 13.0 or 13.1 or 12.9. You want to be slightly on the rich side of your target AFR anyway, for this and other reasons.
 

Robinjo

Goblin Guru
I'm a bit confused with the wiring in the Wideband to the A/C pressure wire. Do I connect the A/C wire into the wires coming from the O2 Sensor to the display or the other connector that has power and all that? I was working on this and the diagram made me question what I though I was supposed to do.

I have the AEM UEGO setup, for reference.
 

Rauq

Goblin Guru
The AC pressure wire input to the ECU should be connected to the white wire that comes off the gauge. The wideband O2 sensor harness only runs between the sensor and the gauge.

47660
 

Robinjo

Goblin Guru
Good thing I asked because I thought it was supposed to connect into the harness from the sensor to the gauge.
 

mike_sno

Goblin Guru
You can set your tune up to minimize adders like piston protection and cat over-temp and log fuel trims and compare to the wideband. I will always trust the narrowband O2 sensors when running closed loop over a wideband, but with enough data and some Excel math, you should be able to verify how close your wideband is at stoich. And if 14.7 is really 14.7, then to me the scaling is relatively trivial, whether 13.0 is 13.0 or 13.1 or 12.9. You want to be slightly on the rich side of your target AFR anyway, for this and other reasons.
Great idea, never thought of using the NB to calibrate the WB.
 
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