Physical ethanol sensor speed?

[krbjmpr]

You know what, it is probably virtual. As far as I know, nothing has been added to the Yukon. Searched for pn and location @ gmparts and doesn't exist, at least not for flex fuel sensor like was on my old 03 pickup.

An aside:
My '03 Silverado had an actual sensor that had to be replaced a few times (contaminated fuel) and eventually reimbursed by fuel distributor when sent sample off to lab. Positive for lead something or other. Horrible mileage, knocking/pinging. In addition to reimbursement, insisted on new (farm) tank to replace contaminated.

 

[hagar]

You know what, it is probably virtual. As far as I know, nothing has been added to the Yukon. Searched for pn and location @ gmparts and doesn't exist, at least not for flex fuel sensor like was on my old 03 pickup.

An aside:
My '03 Silverado had an actual sensor that had to be replaced a few times (contaminated fuel) and eventually reimbursed by fuel distributor when sent sample off to lab. Positive for lead something or other. Horrible mileage, knocking/pinging. In addition to reimbursement, insisted on new (farm) tank to replace contaminated.

If it helps, I have tuned over 4 thousand vehicles, and i still have no idea how the virtual sensors work. I have seen 40 plus trucks now that had the virtual sensor mess up and run crazy rich. I just turn the system off, then set the stoich to 14.2 for 87 octane, and 14.7 with no ethanol fuels. If you know you will never run e85, get that shit deleted in your tune.
It often doesn't even work from good to bad. There are lots of data points between 100 percent, and 60 percent, which is the spread of fuel economy the E sensor uses. You can be driving a bone stock 2010 silverado right now, that is getting horrible mileage, and you don't realize it's the e content sensor.
Most people notice it two years later when it starts blowing smoke and fouling plugs... then they say "oh yeah! Now that I think about it, i was getting half as much out of a tank?"

 

[Fless]

There's a TSB for some years:

E85 Flex Fuel Description

** Found this on another site (https://www.chevelles.com/threads/gm-tech-alcohol-fuel-sensor-question.849586/) However, it should be of great interest to many of us.** E85 compatible vehicles no longer use an alcohol sensor to determine and adjust for the alcohol content of the fuel in the...

www.tahoeyukonforum.com

 

[kbuskill]

If it helps, I have tuned over 4 thousand vehicles, and i still have no idea how the virtual sensors work. I have seen 40 plus trucks now that had the virtual sensor mess up and run crazy rich. I just turn the system off, then set the stoich to 14.2 for 87 octane, and 14.7 with no ethanol fuels. If you know you will never run e85, get that shit deleted in your tune.
It often doesn't even work from good to bad. There are lots of data points between 100 percent, and 60 percent, which is the spread of fuel economy the E sensor uses. You can be driving a bone stock 2010 silverado right now, that is getting horrible mileage, and you don't realize it's the e content sensor.
Most people notice it two years later when it starts blowing smoke and fouling plugs... then they say "oh yeah! Now that I think about it, i was getting half as much out of a tank?"

I had the issue of the virtual sensor causing truck to run rich. The problem was that I had replaced the O2 sensors with the "wrong" sensors. The local Advanced Auto parts computer said they were correct for my truck and it didn't throw any O2 sensor codes but it was clearly a different design when I finally replaced them with the correct ones. It would cause the ethanol percent to slowly rise over the course of several fill-ups. I would reset it with the Tech-2 and it would gradually rise to the 40%-50% range, obviously causing it to dump too much fuel.

Correct sensor on the left in this pic.

Correct sensor on the right in this pic.

That is one of the reasons I decided to install a physical sensor, although after installing the correct O2 sensors I never had any further issues with inaccurate calculations.

 

[krbjmpr]

If it helps, I have tuned over 4 thousand vehicles, and i still have no idea how the virtual sensors work. I have seen 40 plus trucks now that had the virtual sensor mess up and run crazy rich. I just turn the system off, then set the stoich to 14.2 for 87 octane, and 14.7 with no ethanol fuels. If you know you will never run e85, get that shit deleted in your tune.
It often doesn't even work from good to bad. There are lots of data points between 100 percent, and 60 percent, which is the spread of fuel economy the E sensor uses. You can be driving a bone stock 2010 silverado right now, that is getting horrible mileage, and you don't realize it's the e content sensor.
Most people notice it two years later when it starts blowing smoke and fouling plugs... then they say "oh yeah! Now that I think about it, i was getting half as much out of a tank?"

My Yukon is 2012 SLT with 5.3L 6spd, and has 199k miles, possibly 200k now, on the clock. I fill up at a single station, typically at same dispenser on same side when local. Yeah, station is Walmart / Murphy, but works for me. Torque typically reports ethanol in 5-8% range, with a couple Spikes higher when travel to Ft Worth or Lake Charles. Mileage averages 17.5 - 18.4mpg, and I still have AFM present and is used heavily. Have learned how to drive in "Eco V4". Typical commute is 28miles one way, 50-50 highway and surface streets. Original tranny as far as I know. An upcoming move puts commute at 91miles each way until I retire early / find gainful employment closer to new home.

I do fill with e85 occasionally, particularly if in Oklahoma City where is usually 25-75 cents (!!!) cheaper. Truck seems to run better overall on 87 pump gas afterwards.

What could / would a tune do for me? I absolutely loved my F150 XLT w/ Gen1 Coyote and ability to use ForScan. From what I have gathered, I am a year too new to even use Tech2 on the Yukon. Possible to restore Tech2 usability?