2018 Yukon Denali Flex Fuel?

[k_arnold72]

I’d feel more comfortable going lower on the ethanol than higher until we know if it’s reading correctly. I don’t want to run more ethanol than 10% until it’s tuned for it.

Did you ever give it a shot? I'd be curious whether it was actually reading alcohol content or not. I did a very non scientific experiment with a quarter tank of e85 mixed with quarter of 93 and it seemed a little peppier.

 

[Doubeleive]

Many of these later models -- at least the GMT900s -- don't have a physical alcohol sensor -- it's calculated by the engine computer software, based on fuel trim tables.

Are they back to putting sensors in the later models?

No and there is chart online showing where they stopped putting them on after 2016, some 2015's have it and some 2016's then pretty much none after that, I'll have to look and see if I can find it again

 

[Doubeleive]

found it, looks like none of the 6.2l came built for e85 after 2014, but "SOME" of the 5.3l did and it would be noted on the fuel door like any other flex fuel vehicle
unfortunately neither my 18 silverado or 16 suburban have it
I think there is another chart that shows that after 2016 pretty much none of them have e85, even though this chart show's some do that's why there is a *asterisk stating to check the fuel door on 16,17,18

 

[Doubeleive]

found this information also, which explains why after 2016 the amount of E85 vehicles produced dropped by about 2/3's compared to 2014
they lost the CAFE credits (for the most part) they were getting for producing vehicles that could use E85, even though some credits can still be traded and new fuel economy standards were required as well in 2016

In late 2007, CAFE standards received their first overhaul in more than 30 years through the Energy Independence and Security Act of 2007 (EISA), and were set to rise to 35 mpg by the year 2020. However, in May 2009 the Obama Administration announced a new harmonized national policy that will require an average fuel economy standard of 35.5 mpg in 2016.[49] The flex-fuel CAFE credits are scheduled to end in 2016, but because the 2007 EISA made CAFE credits exchangeable between different classes of automobiles and tradable between companies, and also carmakers are allowed to carry over credits for up to five years, the flex-fuel credits accumulated up to 2016 can be carried over and traded until 2020.[50] The CAFE standards proposed in 2011 for the period 2017-2025 will allow flexible-fuel vehicles to receive extra credit but only when the carmakers present data proving how much E85 such vehicles have actually consumed.[51]

 

[Shangaipaddles]

Glad to see you got the a/s. Did you get it to turn off the AFM?

The 2018 Tahoe & Burb 5.3L are flex fuel so it’s still a thing. I almost crab’d myself when I saw a lady filling up a Gen 5 with e85 at the gas station. I didn’t know they still equipped them that late.

It shows the 6.2L didn’t get e85 though. It can be done with a kit I’ve seen on the web. If you have any emission or drive train warranty left be sure to remove the a/s from the truck? Some of the old skool dealership employees that wear tin foil hats are scared shipless of anything without a GM logo.

To turn off AFM and to be able to tune my BCM. Now just going through and playing with the various features too.

Did you ever give it a shot? I'd be curious whether it was actually reading alcohol content or not. I did a very non scientific experiment with a quarter tank of e85 mixed with quarter of 93 and it seemed a little peppier.

I put in 13 gallons of 91 non oxy and so far have used 3/8 of a tank. The AutoSync is still reading ethanol 9%. I'm thinking at this point it's not a real measurement being displayed, but will update once I've used the full tank, just in case.

 

[TwoBigBoys n dog]

Hi, been lurking for awhile but first time posting. I have a 2018 GMC Yukon Denali with 92,000 miles. I just installed the AutoSync device from BTDieselWorks and going through the various pages. Under the powertrain data page, where it lists things like MAP vacuum, engine load, ECT, and the like, there is a value for ethanol, currently showing 9%.
I was under the impression the 15/16 probably had the sensor installed but the fuel files weren’t active, and the 17+ vehicles didn’t have the sensor. But this leads me to believe otherwise? Does anyone have verification that an 18 6.2 has the flex fuel sensor from the factory? Where would the sensor be located so I can visually confirm?
Been learning a lot from here, hope to be able to give back at some point.
Thanks!
_Kevin

My '18 Denali says it requires 'premium' fuel. I have yet to see 'ethanol blend' with 91+ octane. Won't the engine knock and lose performance/ range/ power running on corn power, even when adjusting with a tune and a sensor ?

 

[petethepug]

Here in Cali the refineries pretty much run their equipment like a bakery. No pure blend fuels anymore. Depending on the season they add e85 or other ingredients to create a cocktail that emits fewer emissions. It’s a Cali guberment thing.

In the 70’s our smog was so bad that every lane, on every road had a painted on 2ft wide strip of oil, lead and unburned fuel. The coast was the worst. Cargo ships idled on huge 12 cylinder, 2 stroke diesel generators for shore power while waiting for unload. 2-3 out of every 20 kids brought asthma inhalers to school. Cars now outnumber people in CA. Meh, sorry, sidetracked from my refinery days.

 

[Shangaipaddles]

My '18 Denali says it requires 'premium' fuel. I have yet to see 'ethanol blend' with 91+ octane. Won't the engine knock and lose performance/ range/ power running on corn power, even when adjusting with a tune and a sensor ?

At least around the mid west, all gasoline has up to 10% ethanol in it. You can find pure gas (non oxy) 91 at certain stations, they'll have a separate nozzle/pump for it, but it legally is only allowed in small engines, and vehicles eligible to be registered as a collector, which in Minnesota is 20 years or older. I run either 92 from Costco or 93 from BP or Shell. If I have to, I'll run 91 from Holiday.

With a proper sensor and tuning, you'll make more power on e85 than e10 or e0, as there is more oxygen in the fuel. You need to run more fuel because of that, which is why some vehicles require injector and or pump upgrades. It will run like crap, if at all, running more than e10 without the sensor and tune.

 

[Fless]

My '18 Denali says it requires 'premium' fuel. I have yet to see 'ethanol blend' with 91+ octane. Won't the engine knock and lose performance/ range/ power running on corn power, even when adjusting with a tune and a sensor ?

E85 (which is unlikely to be available at 85% ethanol) has an octane rating north of 100. Lower values (E70, for example) will have slightly lower octane but it'll be above your 91 octane gasoline.

https://www.motortrend.com/how-to/e85-vs-114-octane-race-gas-on-the-dyno-with-a-boosted-small-block/

You will, of course, lose some range running E85, that's to be expected.

 

[Shangaipaddles]

Well I went through the full tank of fuel that was 50% E10 93 and 50% E0 91 and the ethanol reading never changed from 9%. I’m thinking it doesn’t have a sensor, and that it is tuned to run on E9 all the time, and the AutoSync just happens to display it. Once I install the sensor and activate the tuning, it’ll be interesting to see if it will display real time ethanol content. It’ll probably be a couple months until I do that though.