(Just adding this here for reference, originally posted on facebook)
Just to clear up some confusion in regards to flex fuel tuning a standard po1 ls1 pcm. Yes it can be done. You need a 12v feed, a ground and a wire input to the pcm.
Then you need a os change in the pcm. To suit 3bar and flex fuel enabled. (these operating system tunes which read feedback from the sensor were only available in factory american vehicles) chevy tahoe trailblazer and vans etc. They also need to be correct to the setup in your vehicle ie manual or auto (4l60e or 4l80e both different). All available to download from the hpt repository (subject to the new version upgrade etc)
SOME BASE TUNES ARE AVAILABLE BELOW ON THE SLOPPY WIKI ASWELL.
You can reference many helpful pieces of information regarding this here: