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?

 

[Marky Dissod]

What could / would a tune do for me?

Most important thing it can do is improve the longevity / durability of your engine & transmission,
not only by disabling Engine Half@$$ / V4 mode, not only by improving torque converter clutch lockup behavior ...

Most important step in having an ecm & tcm tuned is the driver's due diligence.
Before a tune, customer should speak / email / SMS with tuner,
so they can go over the driver's hopes / expectations / concerns / fears.
No one gets the exact same burger as everyone else at Five Guys - you get it as you like it, just so -
(although Five Guys won't do chicken or fish).
That said, as a mid-90s LT1 tuner myself, I've written tunes for hypermilers, new driving students,
road trippers, different types of autocrossers / road racers, tow-ers / haulers, etc.
They all have some things in common,
but a hypermiler's tune would cause a tow-er / hauler to pull their hair out.

Since you can access a secondary shift personality at the touch of a button,
if you don't Tow / Haul, maybe you want one shift personality to be Dr Jekyl,
and the other be Mr Hyde?

Point is you need to go over all this with your tuner.

 

[krbjmpr]

Hmm
The way you have phrased it, tuning is a one-shot process? Not something that can be further tweaked in real time.

I don't mean to keep referring to Ford, but is what I have (some) experience with. Using a Bully Dog, had all kinds of access to engine management on a 01 F250 7.3L. Injection pressures, duration, turbo pressures, timing, shift points, etc. Could switch between fuel maps at press of a button. My F150, using ForScan, allowed granular access to *everything* that utilized stored firmware and a lot was real time, some others were only key on-engine off.

Seems that any edits to a 'tune' are going to be cumbersome according to the small amount of research done so far.

Appreciate the information.

 

[Marky Dissod]

It is admittedly a pain in the arse to modify your burger AFTER you bit it.
Best tuning option is ALWAYS having the tuner sitting next to you while you drive,
to revise the tune in real time based on your peculiar vehicle and how you drive it.

That said, maybe I shoulda got in to Ford turbodiesel, that BullyDawg sounds AWESOME.
If you want that level of access, you may want to do research frowned upon here:

Go find a hakt version of HP tuna - version 2.2.4 I think (no later!) -
so YOU can learn how to make the changes yourself.
If I had a GMT900, that's what I'd do.

For $700, BlackBear may not be cheap (!), but you do get a year to make revisions.
From experience I can tell you that most changes involve the transmission's 'personalities',
getting the shifts just right sometimes takes more than one try, TOTALLY worth the extra effort.

Ask away. I'm one of those who knows the 'untuned' don't get how they are skrewering themselves.