2020 GMC Sierra and Flex Fuel

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02-15-2022
Neonracr2

2020 GMC Sierra and Flex Fuel

Looking through wiring schematics for the E90 ECM that is controlling a L87 6.2, I?ve noticed a pin is marked as unused. However, it also has a label referring to it as a flex fuel sensor input. Has anyone tried to wire in a GM Flex Fuel sensor and seen any results?
02-20-2022
FastV

i just did one of these the other day. Its pin 42 In he E90 however yes it will read the ethanol and give spark advance accordingly but doesn't seem to change the fueling. I tried to change the flex fuel multiplier and then the truck wouldn't start. seems to be a complete waste of time.

Ryan
03-08-2022
Neonracr2

Thanks Ryan. I appreciate the information. Out of curiosity, what did you use for the install? Previous generation sensor and pigtail ran up to that pin?

Chris
03-08-2022
FastV

Quote:

Originally Posted by Neonracr2

Thanks Ryan. I appreciate the information. Out of curiosity, what did you use for the install? Previous generation sensor and pigtail ran up to that pin?

Chris

I used as Smg flex fuel kit I bought from Texas speed.

Kind regards,
Ryan
08-12-2023
dram1983361

Quote:

Originally Posted by FastV

i just did one of these the other day. Its pin 42 In he E90 however yes it will read the ethanol and give spark advance accordingly but doesn't seem to change the fueling. I tried to change the flex fuel multiplier and then the truck wouldn't start. seems to be a complete waste of time.

Ryan

FastV, did you ever get this figured out to work properly?? The local speed shop I deal with suggested adding a flex fuel sensor but I haven't found any kits specific for E90 ecm trucks. Kinda makes me think it still won't work to this day.