Have an 05 6.0 with factory ecm. Running the GM 13577379 Flex Fuel sensor. Sensor has 12V going to it, ground is good. Wire is ran to I think it was Pin 25 on the blue connector on the ECM. I am running E85 and it reads 0% Ethanol content. Am I hooked into the wrong pin? Or how do you test this sensor? Thanks

 

Gen3's are often disabled in the PCM. They use a calculated FF value.

If you've added the sensor and haven't had it tuned, I'll just about guarantee you it's disabled in the tune.

Quite common with Gen3.

 

This.. what's mentioned above is correct. What's your PCM OS?

 

My tuner enabled it and got it setup but it just wont read. Using HP Tuners. Can anybody confirm which pin for sure I need to run that wire to?

 

According to ls1tech, blue 56.

 

Just enabling it in the tune doesn't always work, many times a matching factory OS that was actually flex fuel has to be flashed in.

 

Just double checked. I do have the wire going to pin 56 on blue connector. Attached tune file if anybody wants to double check how its setup.

 

Not all the tables are present in any tuning format to just turn it on and have it work. You can't just turn it on with tuning software although the option would have you think other wise.

You need to start with a same year model that has flex fuel enabled.

 

The sensor needs 5v not 12v. Find an original tune that has flex fuel, and do an entire segment swap for the operating system.

 

Did you ever fix that cruise surging issue??