i just wired it into the return line, fired the car, running fine, started adding in e85 to my tank filled with pumpgas, and it just clocked up and ran like nothing happened. afr perfect.
wired in sensor
fired on regular pumpgas, saw the (up to 10% sign prove nearly right)
my tank had about 9-10 gallons of gas in it, i started trickling in e85 while it was running approx 5gal
15%
finally emptying the container and hitting approx 32%
awesome part is the default settings were so perfect, i didnt change my fuel at all, dead on while it was idling it never noticed or had a single issue, pretty awesome!