Want to take my 2010 Yukon XL Denali with 180,000 miles for a family trip from Michigan To Florida - Can you help me make this a success!

[alpha_omega]

With a 6.2 in the Denali all I’ve ever run in her is premium. So I can’t begin to talk on the E85 topic. I run non-ethanol in my lawn equipment or a premium mix if I can’t find non-eth, but that’s about as far as my experience goes with the different grades of fuel.

 

[alpha_omega]

@swathdiver and a couple of the other guys dabble in the different grades. Maybe they can chime in.

 

[donjetman]

I drive conservatively and don't tow.
Our 6.2L isn't a flex-fuel vehicle.
I've run 87 octane for a yr, 89 for a yr, and 91/93 for the past 2 yrs. I even done 20-30% mix of e85 with unleaded. Runs great on them all. But I got knock message a time or 2 when running 87 & 89.
Here a data chart someone? here (not me) posted a couple of yrs ago.

 

[donjetman]

Also, with our Denali the lower the octane, the lower the gas mileage.

 

[bobby2175]

Thanks for all of the info! I'm on my 2nd tank of E85 and haven't noticed any issues so far. Truck is running well. Here are my current prices.



Got my @BlackBearPerf tune files installed and WOW - what a difference! I'm up to about 120 miles or so on it so far and it's awesome!

Even with the tune, I'm still running a little rough on idle - I've noticed my idle is a little higher than before. I'm going to see how this goes with E85 for a few more tanks and then decide where to go. I may need to go to plugs and wires next even though they were replaced at the dealer about 60K miles ago. I won't touch this until the spring.

I also started replacing the lighting to LEDs. Got the inside done and moving outside now. Purchased the Diode Dynamics SS3 fog lights, but don't think I'm ready to replace the headlights to LED housings yet. I was thinking about just replacing the halogens with an LED bulb. I've been reading a lot of the posts here - anyone have a recommendation for bulb only?

I'm also now about a month away from my trip - any other things I need to consider? I feel like I'm getting close now!

 

[alpha_omega]

I drive conservatively and don't tow.
Our 6.2L isn't a flex-fuel vehicle.
I've run 87 octane for a yr, 89 for a yr, and 91/93 for the past 2 yrs. I even done 20-30% mix of e85 with unleaded. Runs great on them all. But I got knock message a time or 2 when running 87 & 89.
Here a data chart someone? here (not me) posted a couple of yrs ago.
View attachment 415049

I think this is from @swathdiver if I’m not mistaken. He and I geek out on excel spreadsheets often shared on here and some of the other similar sites.

Not having a flex-fuel vehicle, did you have to change your fuel trim info via tech2? While this table is obviously subjective due to the amount of miles driven in a year, the temp, driver, traffic, weight, pax, inflation…etc. but did you see a difference (other than knock detection) in say E85 & 87 versus running premium. I ask because you have a 6.2 vs the 5.3.

Same goes for @bobby2175 is there a particular reason you’re not running premium?

It makes no difference to me what you guys run, I’m just asking out of curiosity.

 

[bobby2175]

@alpha_omega - my Denali is a flex fuel, but I've been running exclusively 93 for the past 7+ years. I used E85 going way back when gas prices were really high, but I had a dealer tell me not to use it because he was saying it "gums up the fuel system". This comment was in relation to my fuel filter getting clogged up on my flex fuel Impala where I was exclusively using E85 at the time. I hadn't used it since.

Right now, seeing people here using it successfully, I decided to give it a try with the main reason to see if it will clean my injectors and resolve a rough idle. But since it seems to be running well, I may keep doing it for the cost save while taking a small hit to fuel economy.

 

[alpha_omega]

I could be completely wrong, but you might be better off using an actual injection cleaner to do that job, as opposed to using E85. That’s not to say E85 won’t do the job, I’ve just never used it since I have the 6.2.

I’ve always had good luck with Lucas and the ACDelco top end cleaner as well as their injector cleaner (make sure you use the one designed for Flex-Fuel). I’m pretty sure there’s a TSB out regarding this. I’ll have to check my TSB binder. It’s currently in the house and I’m out in the shop at the moment.

 

[BlackBearPerf]

Thanks for all of the info! I'm on my 2nd tank of E85 and haven't noticed any issues so far. Truck is running well. Here are my current prices.

View attachment 415087

Got my @BlackBearPerf tune files installed and WOW - what a difference! I'm up to about 120 miles or so on it so far and it's awesome!

Even with the tune, I'm still running a little rough on idle - I've noticed my idle is a little higher than before. I'm going to see how this goes with E85 for a few more tanks and then decide where to go. I may need to go to plugs and wires next even though they were replaced at the dealer about 60K miles ago. I won't touch this until the spring.

I also started replacing the lighting to LEDs. Got the inside done and moving outside now. Purchased the Diode Dynamics SS3 fog lights, but don't think I'm ready to replace the headlights to LED housings yet. I was thinking about just replacing the halogens with an LED bulb. I've been reading a lot of the posts here - anyone have a recommendation for bulb only?

I'm also now about a month away from my trip - any other things I need to consider? I feel like I'm getting close now!

That is great to hear! Please so send in a follow-up log with the tune loaded for our review and the tuner can see what he can do about the idle.

 

[donjetman]

Not having a flex-fuel vehicle, did you have to change your fuel trim info via tech2? While this table is obviously subjective due to the amount of miles driven in a year, the temp, driver, traffic, weight, pax, inflation…etc. but did you see a difference (other than knock detection) in say E85 & 87 versus running premium. I ask because you have a 6.2 vs the 5.3.

I my case? No, didn't change a thing.
Pulled up to the pumps, put 5 gal of e85 then filled it up the rest of the way with 91/93. Saved about $5/fillup at the time. Same MPG and performance (conservative driving).