E85 in the 4.3 Ecotec3, Yes or No?

[tim5779]

Hey fellas.  New to the site.  Just picked up a new 2017 Sierra 4.3 Ecotec3 a few weeks ago.  As you can see by the pic, I wasted no time in sprucing her up.

 

I did a ton of research on this new V6 prior to buying, and decided to give it a try.

 

Anyway...Ive read alot (mostly from GM sources) talking about the performance benefits with with using E85 in this particular engine.  The numbers are impressive, but I remain skeptical.  Everything I've ever been told about Ethanol in flex fuel motors, is "stay away".  The long term damage on metal components just isnt worth it.  But I'm being led to believe that is no longer an issue with this new V6?  Open to any and all suggestions.  Keep in mind, MPG is not a factor.  My drive to work is 8 miles, and E85 here in Indy is a full $1 cheaper than unleaded per gallon.

[Frank-OH]

Grats on the rig my friend! She is sharp!! I can't speak for the 4.3 performance per say but can say if you plan on using your truck for a truck, your gonna wish you had went for the 5.3. 

[tim5779]

Nah...I've had V8's my whole life.  The decision to go with the 4.3 was really a matter of price.  This was the only 2017 they had left on the lot.  Sticker was 44k, and I took her home for 28k...couldn't pass that up.  I pull a 5×8 trailer with a quad, and haul firewood and lumber occasionally, so at the end of the day, when a deal like that comes along, it makes you think about how you really use the truck, and do you REALLY need a V8.  This 4.3 should be more than enough for the work I need it to do.

[muddkatt]

Does your truck have the "flex fuel"  decal? If not, you shouldn't run e-85. At least that was the way the 15 and 16's were.

[sdeeter19555]

Yellow gas cap?

Steve
2012 2500hd

[tim5779]

Yes it's flex fuel

[Colossus]

Don't run it all the time but here and there won't do any damage.

[DONWT15]

6 hours ago, Colossus said:

Don't run it all the time but here and there won't do any damage.

Why do you say that? Owner's manual actually encourages the use of E85 if the vehicle is equipped (yellow gas cap} and also states it's not recommended to switch back and forth frequently.  

[tim5779]

Thanks Don!  oh and FYI Guys....2017 and up no longer have a gas cap (gas cap free, spring loaded port instead).  But, the window sticker clearly states "E85 flex fuel vehicle".

[bgbdwlf2500]

7 minutes ago, tim5779 said:

Thanks Don!  oh and FYI Guys....2017 and up no longer have a gas cap (gas cap free, spring loaded port instead).  But, the window sticker clearly states "E85 flex fuel vehicle".

If its a flex fuel then I would run it. these engines really aren't designed to run on 87 octane and you will notice the difference running E85 as they run so much better. I run it in my 2010 all the time unless I have a road trip planned. The mpg is horrible though, I think I'm down to 290 or so miles to a tank but I do let my truck warm up pretty much every morning, been colder than normal here in sc 

[DONWT15]

Your welcome. Forgot about the gas cap on the 17's and up. The stickers are good. I would go for it with a price difference that big

[tim5779]

Thanks fellas.  I'm about due for a tank so, I think I'll try it out.

[bgbdwlf2500]

11 minutes ago, tim5779 said:

Thanks fellas.  I'm about due for a tank so, I think I'll try it out.

make sure to read the manual on the procedure for the switch over. my truck has to be driven at least 7 miles on the switch over for the sensors to pick up ethanol content. once that happens you will feel the difference

[sdeeter19555]

make sure to read the manual on the procedure for the switch over. my truck has to be driven at least 7 miles on the switch over for the sensors to pick up ethanol content. once that happens you will feel the difference

Read, but dont get hung up on the procedure.

With the varied alcohol to gasoline content of most flex fuel, you will likely find that you rarely get a true e-85, as "Flex Fuel" can be anywhere from 51% to 85%...it should be marked on the pump.

I'm completely converted to "Flex Fuel" now, and I'm only at 66% alcohol. It should go back up during the summer if things hold...these modern Flex Fuel vehicles don't care what percentage you run, they adjust on the fly. These trucks do report alcohol content, you need just need a way to reading it...I can see it through my Edge Insight. That's why I say not to worry about following the manual, you don't need to run the tank low to switch over.

The ECM doesn't make a determination to alcohol content for about seven to eight miles. And contrary to Internet lore, the system routinely samples the alcohol content in fuel anytime the truck is running, and adjusts as necessary; not just after you fill up. Mine will change everyday...

When they do finally make a determination to the content, they immediately run/feel different. If you have a catch can, watch it closely as they tend to fill up with water fast.

Steve
2012 2500hd 6.0l

[tim5779]

1 hour ago, bgbdwlf2500 said:

If its a flex fuel then I would run it. these engines really aren't designed to run on 87 octane and you will notice the difference running E85 as they run so much better. I run it in my 2010 all the time unless I have a road trip planned. The mpg is horrible though, I think I'm down to 290 or so miles to a tank but I do let my truck warm up pretty much every morning, been colder than normal here in sc 

So you've ran E85 for 8 years and haven't seen any negative affects on the fuel system?  Or did you just begin to run it recently?