Being able to run E85 and Gasoline on a whim, without lugging a laptop to switch tunes, or draining your tank between the 2, is now gone as long as you have an ethanol sensor installed. I wont cover how to install the actual sensor into your fuel system since that is already covered on the internet, but the high-view of what you do is you stick it on the return line (I don't think there is enough flow in the stock system to use it there) and run some wires into the cabin and here you are. Hondata recommends the 13577429 part from GM, so that is what I will be going over here.

You will have 3 wires, either you got the other part number 13352241 or found a pigtail-type kit elsewhere. If you are using the part number listed you have 3 colored wires, White, Pink and Black. White is your sensor output, Pink is switched ignition, and black is ground. You will want to use the same ground as ECU. The white wire you will connect to the Digital input pin labeled "Eth" which is next to the ground pin of the pin header.

Open up your kal file and go to Parameters > Flex Fuel and check the box to enable the flex fuel sensor.

Open the Display window and right click in its background, select New Value.

On the new "RPM" display, right click on it and go to Sensor > KPro4 > Ethanol Content.

Turn on datalogging (Lightning Bolt button) and prime/start the car. That value in the display should start to change. Give it a couple minutes to update, if it doesn't double check your wiring to make sure the sensor is getting power and ground, and that there is continuity between the ends of the sensor wire and that you are in fact on the Eth pin.

Once you get this set up, you can then start working on your ethanol compensation tables. KPro already has the ethanol sensor values built in, so all you need to do is figure out how much more fuel/ignition/boost you need to run for the various ethanol contents.

It is pretty simple so I didn't include pictures, and you can also google up those pictures including the v4 digital input pins.
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