Snowman916

I installed an AEM UEGO sensor and gauge in my Evo 6 over this last weekend, and all I have left to do is connect the analog output wires from the gauge for datalogging (I picked up the analog version which does not support serial logging). I have read that this is possible by splicing into the factory rear o2 wiring on the newer Evos, but I didn't realize until finishing the rest of the installation that these older JDM models did not come with one... I did some digging and found that there is supposedly an ecu pin for a rear o2 sensor on these cars, it just may not be used (pin 54 if I remember correctly?).

Would it be possible to use this pin or another unused pin to send the signal, and use Evoscan to log the data as long as the appropriate address is referenced in the ROM? If not, do I have any other options?

Snowman916

UPDATE:

Turns out it is possible! I was able to log the UEGO analog signal by wiring the 0-5V+ wire to pin 75 on the ecu (pin 54 is the heater circuit, 75 is the signal input). As long as the hex address in your MUT table is correct (by default it is at address 3C), Evoscan can now log this signal.

To calibrate it, I used a camera mounted on my steering wheel to record both the tach and the wb gauge during a few pulls. I also logged the wideband signal in evoscan without any conversion (y=x). I then plotted some data points from the video against the corresponding points from the log, and came up with the conversion formula AFR = 0.0449x + 7.4454. I plan on taking a few more videos for comparison to make sure the gauge and log values match up.

Trevan00

Hey man,


Great work! I am trying to do the same thing.. Did you make any progress with the calibration? Also what evoscan output are you using to log in evoscan?


Cheers,
Trev

Snowman916

So far that same formula has been working pretty well! It may be off slightly now because I changed the way it was wired, but no not by much. In Evoscan I used the "Rear o2" output and renamed it to "AEM UEGO", but you should be able to use any of the unused ones so long as your MUT address and formula are correct.