Quote Originally Posted by darkhorizon View Post
I could probably design a flex fuel sensor that works, but its not worth it.

GM cars that are flex fuel dont even use a flex sensor, they just use the o2 sensor.
Gm cars used both, the majority use a external physical flex fuel sensor with a alcohol %table to adjust the stoich.

Gm tried using a virtual flex fuel algorithm for a couple years but went back to a physical sensor.

Keep in mind with that the car needs to have a voltage input based off of stomach that changes the master stomach table for the car to run correct.

I find it easier just to reflash the car between summer/winter blend