Quote Originally Posted by Jim_Rockford View Post
thats funny cause Im running 5-6 gallons of E85 in addition to 87 e10 in a 22 gallon tank at fill ups. think that is causing the O2 to think its lean and trying to fatten it up?
A narrowband O2 reads rich or lean from stoichiometric no matter the fuel. Adding extra ethanol into the fuel when using a gasoline tune should cause the BLM values to go above 128 since the engine would require more fuel to remain at stoichiometric. Same driving condition = same air but the same air requires more ethanol fuel mass then straight gasoline fuel mass.