E85...any reason Not to use it?

[gooffeyguy]

I had to drop the alcohol content on gas to 0% and E85 to 29% to get 13% with the amounts you pumped in. I suspect she's not done computing. Did the trims level out at zero while cruising steady or are they still jumping around? Mine takes about twenty miles to settle down usually but I've checked a few days later sometimes and it had changed again.

I've used almost a half a tank since getting gas and it's still showing 12.9% ethanol. My LTFT while cruising steadily on the highway will range from about 8 to 12. Around town it's lower, in the 2-5 range.


2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[swathdiver]

I've used almost a half a tank since getting gas and it's still showing 12.9% ethanol. My LTFT while cruising steadily on the highway will range from about 8 to 12. Around town it's lower, in the 2-5 range.


2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

Mine runs the opposite usually. At highway speeds they zero out but stop and go they go up and at lower cruising speeds such as 40 mph they might be -3 or -5. Depends on the alcohol content too. It's an observation and not something I've tracked.

 

[HiHoeSilver]

I've used almost a half a tank since getting gas and it's still showing 12.9% ethanol. My LTFT while cruising steadily on the highway will range from about 8 to 12. Around town it's lower, in the 2-5 range.


2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

Your trims are high because the calculated E% is lower than actual.

At this point, I would force a refueling event (put in more than 3 gallons) under the conditions I mentioned in my previous posts. Engine at full operating temp, followed by 7+ miles of driving.

I'm curious about more thing here that I haven't yet dug into. When you're mixing fuels, do you start the truck for just a few seconds and drive it over to a different pump? I'm assuming so and am not sure yet how that may /may not affect the VFFS calcs. Same question for you James. @swathdiver

 

[swathdiver]

Your trims are high because the calculated E% is lower than actual.

At this point, I would force a refueling event (put in more than 3 gallons) under the conditions I mentioned in my previous posts. Engine at full operating temp, followed by 7+ miles of driving.

I'm curious about more thing here that I haven't yet dug into. When you're mixing fuels, do you start the truck for just a few seconds and drive it over to a different pump? I'm assuming so and am not sure yet how that may /may not affect the VFFS calcs. Same question for you James. @swathdiver

I think's Tom is fine with his current mix, the trims are constantly adjusting and while driving it's tough to pay attention to them. Sometimes I'll do a data log with the Tech-2 or AutoCal and view it later on the computer, or get my daughter to drive while I play with the Tech-2.

As for your question, it has not mattered in my experience. I almost always refuel with the engine running too. A couple of weeks ago I refueled and then got the "We're hungry!" from the crew in the back seats, so we pulled right next door to Golden Corral. The relearn went off without a hitch afterwards and took the usual 18 miles to settle down on a number.

 

[gooffeyguy]

Your trims are high because the calculated E% is lower than actual.

At this point, I would force a refueling event (put in more than 3 gallons) under the conditions I mentioned in my previous posts. Engine at full operating temp, followed by 7+ miles of driving.

I'm curious about more thing here that I haven't yet dug into. When you're mixing fuels, do you start the truck for just a few seconds and drive it over to a different pump? I'm assuming so and am not sure yet how that may /may not affect the VFFS calcs. Same question for you James. @swathdiver

Same pump, different handle.

I stopped on my way home from work and the engine was up to temp. Shut off while fueling and not started until I was done. I only drove about 4-5 miles after that before arriving home.

I had 9 gallons of 93 octane in the tank before fueling with a 9% ethanol content showing on the gauge. I pumped 12 gallons of E85 then 10 gallons of 87 octane. I have no idea the % of E85 I pumped in, but from using this same station in the past it has ranged from 63% - 77% ethanol.

Ive got some running to do today, about 15-20 miles each way, and will top off the ~10 gallons and see what happens.

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18