Sensor and Wiring
The following Sensors are known to work
GM part numbers
13577379 - SENSOR (short tube)
13577394 - SENSOR (long tube)
13352241 - HARNESS
The Pinout is shown below
Connect your sensor to a digital input on the ECU. Then, pick the pin in TunerStudio at
Sensors -> Misc sensors -> Flex fuel sensor.
(technical details - we expect a pull-up on the ECU, about 3K, somewhere 1K to 5K)
Fuel -> Injection Configuration, configure
Stoichiometric ratio and
E100 stoichiometric ratio. Unless you're doing something very weird, 14.7 and 9.0 are the correct values respectively (pure gas has a stoich ratio of 14.7:1, and pure ethanol 9.0:1).
That's it! The firmware will now automatically vary the fuel's stoichiometric ratio based on ethanol content.
It's recommended to switch to lambda mode (
File -> Vehicle Projects -> Project Properties -> Settings -> Lambda Display), as the target lambda table is multiplied by the current stoichiometric ratio to get the target air/fuel ratio.