My L59 is Flex as well (all L59s are), Flex also indicated by the 'Z' in the VIN.
Filled up my sisters E85 Yukon ...now runs like crap.
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My L59 is Flex as well (all L59s are), Flex also indicated by the 'Z' in the VIN.
HiHoeSilver
Away!
Gotta be L59. All aluminum FFV.
All aluminum? My L59 block is iron.
HiHoeSilver
Away!
Duh, you're right. Why did I think that? I have one. Lol. L33 I was thinking of, maybe?
Now I am lost, ALMOST. How many "L" codes are we gonna throw out there? L29 then L59 and now L33. 
BINGO!Now I am lost, ALMOST. How many "L" codes are we gonna throw out there? L29 then L59 and now L33.
gooffeyguy
Tom
Let's not forget L94
2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18
2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18
Now I am lost, ALMOST. How many "L" codes are we gonna throw out there? L29 then L59 and now L33.
Hopefully not many; GM has hundreds of L-codes for engines. My RPO Master List starts at L01 for engines, and after L97 it restarts with LA1, LA2, and goes on and on. Obviously a small percentage have been in our truck builds.
@HiHoeSilver you're correct that the L33 is aluminum.
danielnorris
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Even if the vehicle is capable of running E85 the computer has to be programmed for it to run properly. You can't switch back and forth between flex fuel and regular fuel. I found this out by doing the same thing in my wife's Ford 500. My advice would be to run as much of the fuel out of the tank and refill with good gas and repeat for a couple of tanks. Get ready for some crappy mileage until it gets cleared out.
HiHoeSilver
Away!
Absolutely wrong. An FFV is just that... FLEXIBLE in the fuel it can run on. I swap back and forth all the time as do many here.
No tuning is necessary. There is either a physical or virtual sensor that calculates the ethanol % of the fuel and adjusts the tables accordingly.
In the case that you are running a custom tune (I am, for example), one suited for higher octane may produce better results with e85 than an 87/89 tune, as the ethanol can take advantage of the high octane timing, but it certainly isn't required in any way.
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LOL I appreciate you including my experience in that group, Nate. I run varying percentages of ethanol and have not had any trouble with switching back and forth. The only issue that I have with higher percentages of ethanol is during cold starts. It can take mine a bit longer cranking to fire up.
@HiHoeSilver speaks truth!
You can switch between E85 and 0% every other tank if you want. My wife only puts 89 octane with 15% alcohol in and I frequently put E85 into our Yukon with no issues. The computer goes into a recalibrate mode when it senses that you added fuel and determines the effective alcohol content then makes the necessary adjustments to optimize for that fuel blend.
You can switch between E85 and 0% every other tank if you want. My wife only puts 89 octane with 15% alcohol in and I frequently put E85 into our Yukon with no issues. The computer goes into a recalibrate mode when it senses that you added fuel and determines the effective alcohol content then makes the necessary adjustments to optimize for that fuel blend.
HiHoeSilver
Away!
Agreed. It's getting to that point here when I will load the 87/89 tune and run the mid grade for the winter. The other benefit is not having to stand outside at the pump as often!
Here in Oregon it is a state law that the station has workers that always pump the gas. I watch them like a hawk and only use my Chevron 1/4 block away. The only exception is what we call card lock stations where you pump your own at a discount but you have to join them to be allowed to do it and sometimes the locations are few and far between.
HiHoeSilver
Away!
Always wondered about this. Why in the world do you think that's still a law there?
It's the governments answer to creating jobs and forcing it on the business owner. The premise they used in the beginning was that it was safer for the business to pump instead of the driver. I never let them check under my hood but they never really ask to do so. The ask about the windows and I let them do that. I always pay cash and tip the guy/girl $2 and they look for me when I pull in and hustle over to pump the fuel. If it is a newbie they take there time to mosey over to my rig. I welcome them more in the cold and wet weather of course.
HiHoeSilver
Away!
Is this a high school job?
Lots are very young but some are older. Some, I feel, are retired and just making some extra money. I had my first gas pumping job, gas jockey, at a full service station when I was in high school. Learned that cleaning windows correctly was an art. This was a farming community so there was lots of bugs in the air. It is a basic job that hopefully teaches youngsters to be on time and actually work for money instead of getting a gov handout. Teaches them to work hard and move up the ladder. I have also met my fair share of complete idiots that had a hard time doing just rudimentary tasks.
I’m sure your per gallon price suffers with it being pumped by someone else too
Yes, the price is higher. Just because I am in such a liberal state that the state tacks on taxes after taxes to the price of fuel on top of the higher cost of fuel here because of the gov wanting us to all ride buses or drive electric cars. I do my shopping at Safeway and Chevron is tied wit them somehow and I get $.10 to $.20 a gallon discounts depending on how much I spend at Safeway. It helps. That is at any Chevron in the state.
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