Gadgetized, could you be more specific on what you did???

My understanding is the 05-07 classic pickup's use a virtual flex fuel table based on 02 sensor feedback. In other words no sensor needed.

I have an 06 Flex fuel truck.

I know the 02 PCM is different and requires the sensor.

I have read from several people that trying to enable the flex fuel option in a non flex fuel OS does not work as there are other tables that are not populated In the Tuning suites. You have to full flash a Flex Fuel OS inn order for it to work.

 

There's obviously an OS out there for the 1mb pcms which uses the sensor (probably 03-04).

Virtual flex fuel is BS.

 

Did a bit of digging. Seems like we need OS 12579405:
Flex fuel addition

OS 12579405 available here (must have HPT login or PM me and I can email you the file):
https://www.hptuners.com/customers/t...wnload&id=1452

 

I used EFI Live. My truck came with 12592618. I found a flex fuel OS on tune file depot. I flashed in the flex fuel 12592618. I run speed density so I used my MAF 5v reference to supply the power. I used one of the other wires from the MAF to run to pin 56 of the blue connector. I am able to log ethanol content with my V2, and the commanded AFR changes as the ethanol content rises. I had to change the AFR slope slightly based on wideband input with the fuel trims disabled. First I tuned the truck on pump gas and then left the Main VE alone. When I added ethanol it was slightly off at higher ethanol content. I adjusted the commanded AFR vs ethanol content table with the fuel trims disabled until it was good. I then enabled the trims. I'm very happy I did it. Last time I went to the track I was at 70% ethanol, and it ran great. Any amount I put in the truck it runs great.

 

Sweet! Seems there are many OS's that can be used, I did a search in the tune repository for "P59 flex" and there were quite a few. I just picked one from my same year and engine size.

What kinda ET's are you running?

 

Not very good. My quickest was 11.34@129 easing off the line and getting out of the gas once due to tire spin. My fastest was 11.43@133 easing off the line and getting off of the gas 3 times due to tire spin. I have slicks that will be mounted in a few weeks.

 

What operating system do you have? I personally like 12592618 the bes . It is offered in DBW, and DBC, 4l60e, and 4l80e, offers flex fuel, and you can adjust very short pulse widths for exactly this situation. Big injectors and pump gas when they require a very short pulse width.

 

HPT is telling me my current OS is 12592618. So it seems like I'm already setup lol