Is it oxygen being added or hydrogen, or both?
Since you are sending both the h2 and the o2 in, they burn perfectly, and the o2 sensor reads NORMALLY.no extra o2, cause it all burned up the h2 back to water, duh. No adjustments needed. The gazzaline burns the air from the intake, burns normally and the ecu adjusts it with tweaking the fuel input.
Since the HHO bull**** burns perfectly it need no adjustment, bubba.
This is all besides the point that you are losing more energy splitting the h2o than you get from burning it again. Duh.
God, you should know this from any high school physics, if you passed, or even took it.