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E85 in non-FlexFuel 5.3

6sigma

By 6sigma
in Engines & Drivetrain

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6sigma Enthusiast

6sigma

Posted
  • Author
Posted

So you are running E85 on a vehicle not suited to run on it?

 

I'm running E85 in my 2015 5.3 without the FFV option. It runs it EXACTLY as I have experienced in previous FFV trucks and as others have reported on the 14+ FFV 5.3s. It is more responsive, smoother, shifts better, and seems to have more power. It is getting approx 20% less MPG, which means it is adjusting fuel injection for the increased ethanol content.

bigsapper Enthusiast

bigsapper

Posted
Posted

 

I'm running E85 in my 2015 5.3 without the FFV option. It runs it EXACTLY as I have experienced in previous FFV trucks and as others have reported on the 14+ FFV 5.3s. It is more responsive, smoother, shifts better, and seems to have more power. It is getting approx 20% less MPG, which means it is adjusting fuel injection for the increased ethanol content.

 

Can you go look at the RPO codes on your glovebox and tell us if you have either or both of these RPO codes?

FHO

FHS

POS VETT Enthusiast

POS VETT

Posted
Posted

So you are running E85 on a vehicle not suited to run on it?

In a nutshell, yes.

6sigma Enthusiast

6sigma

Posted
  • Author
Posted

 

Can you go look at the RPO codes on your glovebox and tell us if you have either or both of these RPO codes?

FHO

FHS

 

It has FHO but does not have FHS. This is a 2015 Sierra DC, 4x4, SLE with the 5.3, if that matters.

Chris Senior Enthusiast

Chris

Posted
Posted

 

It has FHO but does not have FHS. This is a 2015 Sierra DC, 4x4, SLE with the 5.3, if that matters.

FHO is to use E10, FHS is is E85
bigsapper Enthusiast

bigsapper

Posted
Posted

 

It has FHO but does not have FHS. This is a 2015 Sierra DC, 4x4, SLE with the 5.3, if that matters.

 

Yeah, I wouldn't be running E85. The FHS option provides an alcohol sensor & enables the correct tables in the ECM.

redwngr Senior Enthusiast

redwngr

Posted
Posted (edited)

 

It has FHO but does not have FHS. This is a 2015 Sierra DC, 4x4, SLE with the 5.3, if that matters.

Without FHS it won't have the ethanol sensor.

 

For 2015 Sierra:

FHS NEW! E85 FlexFuel capable
- Included with (LV3) 4.3L EcoTec3 V6 engine. Available to order with (L83) 5.3L EcoTec3 V8 engine.
(In 2014 it was standard on 5.3 as well)
(In 2015 it is 0ptional with (L83) 5.3L EcoTec3 V8 engine with (MYC) 6-speed automatic transmission or included with (LV3) 4.3L EcoTec3 V6 engine.) ---- which means it is not available in combination with the 8 speed transmission
Edited by redwngr
bigsapper Enthusiast

bigsapper

Posted
Posted

 

... which means it is not available in combination with the 8 speed transmission

 

 

Wow, nice catch there.

redwngr Senior Enthusiast

redwngr

Posted
Posted

 

Wow, nice catch there.

Yes, I really wanted to add it to my 2016 (SLT/5.3/8spd/max tow) -- but it can't be done (through GM).

DirtyMarcus Enthusiast

DirtyMarcus

Posted
Posted

Just do the next potential owner of the truck a big favor if you keep running E85. Let them know you continuously ran E85 in the truck, even though its not E85 compatible. Theres more to it than having bigger injectors and pump.

  • 4 years later...
Meadows New Member

Meadows

Posted
Posted

I know this is an old post, but I just rebuilt a 14 Silverado that was a total. I used a engine / chassis from a 15 Silverado that was a rollover but good straight frame. I used the 14 engine computer since it worked with the key from the 14 cab.  I have the code for the ethanol sensor because the 15 frame didn't use it.  My question is how to reprogram the ecm, or can it be to eliminate this code from staying on.  Or how could I add the sensor so the computer would see it.  I tried the 15 ecm and reprogramming the key but it didnt work.?? It put it in theft mode.  Do you have to use a new chip key for the key program to work? I was trying to reprogram the original key?  Runs perfect other than the check engine light on. I'm not in an emission county so doesnt bother me til it's time to sell.  Thanks

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

The 2015 computer doesn't work because it would require a full program flash to the match the PCM and TCM, then the key needs to be programmed.

 

The 2014 can be tuned with an aftermarket tuner to disable the flex fuel system and remove the codes.

 

Or you can steal the flex fuel sensor and hard line off the 2014 frame and install it back on the 2015 frame. Or buy a new sensor, plumb it in near the fuel tank and extend the wiring to reach it.

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