Want to go E85 on my 16 Sierra CC 4x4 6.2L

Donstar · July 22, 2018

Yellow gas caps are a quick way of determining if a truck is E85 compatible. I'm currently shopping for a truck and wondering if there is a quick way to determine this with capless fuel fillers?

Gorske · July 22, 2018

19 minutes ago, Donstar said:

Yellow gas caps are a quick way of determining if a truck is E85 compatible. I'm currently shopping for a truck and wondering if there is a quick way to determine this with capless fuel fillers?

There should be a yellow flex fuel sticker on the inside of the gas door or a transparent flex fuel sticker on the lower right corner of the drivers door window as well. 2017+ flex fuel 5.3s seem to be pretty rare where I am. I got a non flex fuel truck and just did the flex fuel mod.

Edited July 22, 2018 by Gorske

TJay74 · July 22, 2018

8 hours ago, KARNUT said:

This is the type of response I was hoping for, instead of your an idiot if you don’t see the benefits. I ask questions.

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No one ever said anyone is an idiot, but when people come into posts without fully knowing how the system works and or tells people there are no gains it makes people question who is correct.

1st off, the 5.3 trucks shouldnt even be running 87 AT ALL...!!! Those trucks have detonation on 87, 89 and on 91. The compression ratio isnt that far off from the 6.2 trucks. Sadly people get fixated on the fuel costs and to be honest the vast majority of owners will run the cheapest stuff they can find.

The only way E85 will have a octane rating around 94 is if it is not really E85 and is closer to E65 which does happen as some stations switch over to the winter blend on E85 in the fall. Our main station is Oncue, they do this. We do have a private owned station who keeps pure E85 all year long as well as E100. So luckily we can use either one to get the E value up faster without having to run so many tanks thru the vehicle.

As said, Ethanol has benefits other than just being able to run more timing. It burns cooler, it burns cleaner and it wont leave carbon fouling on the valves, pistons, rings, or any of the other parts. I recently had some work done on my truck, with the Ethanol I had put in the system over the last several months and the catch can as well the tech said I didnt have any carbon build up on my valves or on the pistons when he used the bore scope to check out a couple of cylinders.

I am looking forward to the gains on the E85 in the next week or so, I may at some point put my wideband in the exhaust as well and maybe see if I can dial in the PE tables as well. One day my goal is to go out to Florida and go to the Tuning School and learn some more of the tuning side of the new vehicles.

Nick The Great · July 23, 2018

22 hours ago, Donstar said:

Yellow gas caps are a quick way of determining if a truck is E85 compatible. I'm currently shopping for a truck and wondering if there is a quick way to determine this with capless fuel fillers?

With the GMT900's you could check a digit of the VIN. Not sure if that's true of the k2's.

KARNUT · July 23, 2018

No one ever said anyone is an idiot, but when people come into posts without fully knowing how the system works and or tells people there are no gains it makes people question who is correct.

1st off, the 5.3 trucks shouldnt even be running 87 AT ALL...!!! Those trucks have detonation on 87, 89 and on 91. The compression ratio isnt that far off from the 6.2 trucks. Sadly people get fixated on the fuel costs and to be honest the vast majority of owners will run the cheapest stuff they can find.

The only way E85 will have a octane rating around 94 is if it is not really E85 and is closer to E65 which does happen as some stations switch over to the winter blend on E85 in the fall. Our main station is Oncue, they do this. We do have a private owned station who keeps pure E85 all year long as well as E100. So luckily we can use either one to get the E value up faster without having to run so many tanks thru the vehicle.

As said, Ethanol has benefits other than just being able to run more timing. It burns cooler, it burns cleaner and it wont leave carbon fouling on the valves, pistons, rings, or any of the other parts. I recently had some work done on my truck, with the Ethanol I had put in the system over the last several months and the catch can as well the tech said I didnt have any carbon build up on my valves or on the pistons when he used the bore scope to check out a couple of cylinders.

I am looking forward to the gains on the E85 in the next week or so, I may at some point put my wideband in the exhaust as well and maybe see if I can dial in the PE tables as well. One day my goal is to go out to Florida and go to the Tuning School and learn some more of the tuning side of the new vehicles.

In early 2014 there was a lot of data logging of the 5.3s and it was determined that on reg gas there was some KR. It was determined it was best to run mid grade to eliminate that, although it wasn’t said to cause harm not to. Ultimately E-85 was the best choice, in most cases it was cheaper doing so. It was also determined that the E-85 blend could be all over the place. It was called fueling events and blends were posted. Even lower blends were beneficial with the 5.3. I found a local E85 station that had reliable fuel. On trips I ran mid grade gas. The 5.3 was upgraded in the 2014 model year so there was some excitement around the E-85 boost to get within 40HP of the 6.2 without any other mods. The 6.2 wasn’t offering the same option and at the time GM wasn’t make it very plentiful. Good luck on your schooling.

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wforrest08 · July 23, 2018

On 7/22/2018 at 10:08 AM, Donstar said:

Yellow gas caps are a quick way of determining if a truck is E85 compatible. I'm currently shopping for a truck and wondering if there is a quick way to determine this with capless fuel fillers?

The E85 window sticker is great unless the previous owner is like me and peeled if off when I debadged everything eles...

Here’s the RPO codes

FHO: Vehicle Fuel Gasoline E10 (NOT FlexFuel)

FHS: Vehicle Fuel Gasoline E85 (FlexFuel Truck)

18s you need a reader to get them off the bar code sticker on the drivers door since there’s no sticker in the glove box anymore, obviously new ones will say on the window sticker if E85 compatible, if all else fails stick your head under the truck and look for the sensor in the fuel line even if the sensor isn’t there the 3 wire connector will be there on 5.3L trucks anyway. A lot of dealerships around here anyway on their website you can look at a copy of the window sticker (new or used) this is what I try and use since every dealer list options in their own special way...

SkiDooNick700 · August 7, 2018

@TJay74 any update?

Denali_King · August 8, 2018

Mine gets tuned by Carl Friday at CJ Tunes. I will post up the results.

SkiDooNick700 · August 9, 2018

2 hours ago, Denali_King said:

Mine gets tuned by Carl Friday at CJ Tunes. I will post up the results.

Cant wait to hear back. Bummed hes like 10hrs away from me lol.

TJay74 · August 10, 2018

I am up and running, took about 2 tanks of adding E100 to get me over the E80 point. Sadly that was a temp fix as the station with the E100 is too far away to use them regularly. The local station that has E85 on the pump is not consistent, they range from E65 to E85 depending on the time of the year. The last modifier table is at E80, so as long as you are over E80 will be getting the max tune changes possible.

Truck is running great, defiantly can tell it has picked up some power with the E85 conversion and the Katech ported throttle body.

M1ck3y · August 14, 2018

Did you try the throttle body before you did e85?

Edited August 14, 2018 by M1ck3y

TJay74 · August 19, 2018

Yes fr about a week, but 10rwhp isnt going to make a huge change in performance. 30ish RWHP will make a change though, truck feels great now. Been working on my transmission tune for the last week or two. Once the weather cools off the truck is gonna be an even bigger beast.

nbennettksu · January 29, 2021

Bump!

@TJay74, any downsides to running E85 on the long haul? I ran E85 for a while on my last M3, the turbo’d setup 2015+; only injector issues.

Curious if you had any negatives?

CamGTP · January 29, 2021

No real downsides anymore other than hard starts in the real cold months and worse fuel mileage.

Everything is pretty much a hard line, be it the plastic or metal lines. So no real worries about rubber lines or plugging anything up. I haven't had any issues on the past two trucks with running E85.

nbennettksu · February 3, 2021

On 1/28/2021 at 10:31 PM, CamGTP said:

No real downsides anymore other than hard starts in the real cold months and worse fuel mileage.

Everything is pretty much a hard line, be it the plastic or metal lines. So no real worries about rubber lines or plugging anything up. I haven't had any issues on the past two trucks with running E85.

Thanks! Just ordered everything I need