My truck is E85 compatible and it doesn't have a yellow gas cap... My concern would be that if you think it should have that yellow cap to mark it as E85, then you may want to confirm the truck itself is indeed E85 compatible.

You shouldn't have to pay extra for the cap..

 

I always thought E85 and yellow gas caps came together from the factory. I would look online for a yellow gas cap before I would buy it from a dealer

 

look at the RPO code list in the vehicle glove compartment. You should see RPO code: FHS - VEHICLE FUEL GASOLINE E85 if your truck is E85 compatible. And if it is, I would expect that it would come from the factory with a yellow gas cap.

 

Well, given the way OEM's like to standardize components in vehicle platform building, I would be willing to bet that everything is in place for the engine to be a flex fuel. All that it would take is an ECM reprogram. OEM's do not like keeping different components lying around for assembly. They will use the same pumps, lines, injectors, etc in all the engines and vehicle of a particular class to be more efficient in the assembly process and logistics. I have been on the logistics side of the OEM assembly game for a lot of years. They are going to streamline every process. You would be amazed at the cost savings by doing this.

The $100 uncharge for E85 would explain things. It is just an ECM reprogram.

 

Copperhead: You could be right. Just like the remote start system they have where it is installed on almost every truck but only activated on some. It just seems the cost of adding the Flex fuel capability to all motors would entail quite a bit more than a few wires and a computer flash but I could be wrong. I suppose the cost of extra parts, extra configurations, extra assembly lines, etc... would be enough of an incentive to make them all the same and capable for E85.
I suppose GM has researched the possibility of enabling it on all vehicles since it is already in place and wouldn't cost any thing for them to do so. And then they could use that as an advertising point.
The one part of these trucks that I wish GM would make "optional" that they currently do not is the choice to have AFM or not have AFM.

 

There is more to the E85 vehicles than just a program. These trucks utilize fuel composition sensors.

 

That is true, but as I stated, the logistic of vehicle assembly is such that it makes absolutely no sense to keep batches of different components on a line based on whether an engine will be "classed" as a flexfuel or not. Not when we are talking about the 5.3L like we are here. There is standardization across the vehicle platform. All 1500 pickups, with the 5.3L are gong to be flexfuel capable, even if they are not specified as such to the end user. The bulk of them are specified as such, and it makes no sense to build a handful that have altogether different components that are not. That is stupidity of several magnitudes from an OEM assembly and logistics standpoint. But I suppose it could happen, as GM has employed some pretty dim bulbs in management before.

 

Ragsmatt: Sure they do along with other components necessary for E85 capability. However, I think Copperhead is stating that it is possible all/most trucks already have these components in place from the factory and only a simple reprogramming or minor alterations to the truck is necessary to activate the system, much like the remote start. Yes/No????

 

no.

 

Yes.

 

Can somone out there chime in on this point that has an LC9 motor WITHOUT E85 capability?

Here is the LC9 RPO code description: LC9 14364 P ENG M ENGINE FLEXIBLE FUEL, (GAS/ALC), 8 CYL, 5.3L, SFI, ALUM, CYL DEACTIVATION, GM

To me, this says that any LC9 motor will be E85 capable. And I think a huge percentage of our trucks utilize the LC9 aluminum block motors. This is saying that all are E85 capable. Some may just not have it activated.

 

Yes.

No.

 

Well if my deal goes through tomorrow I will be able to report back. This is a complete BS to make this a $100 option as it was standard last year! E85 goes for 40-60% less than the regular gas. Even with %20 loss of MPG it's still a great deal. Just before New Year I filed it up at $0.79 per gallon! It went up a bit since then, however it is still a money saving feature.
They also completely eliminated the HD radio feature! Why, it was already engineered, tested, etc...a few of my favorite stations broadcast in HD, and now that's gone

 

E85 prices must vary on location. When I tried using it on my '11 I lost on avg $15 per tank in lost MPG. I didn't care one bit that my '15 didn't have E85, didn't even know it was an available upgrade.

 

just spoke with a friend of mine who works for GM. He gets to drive every new vehicle to "spot" any possible problem before the vehicles go to production. ( actually he gets paid to "abuse" pre-production vehicles to find any weak links). He thinks it's probably a fuel mix sensor somewhere in the fuel line/fuel system. Depending on the system design, it could be just a simple add on, but he wasn't sure. He will talk to someone in their engineering dpt and let me know if it is possible to upgrade.
E85 saves me $500-$600 year...

 

When gas got down to 279 per gallon here I could buy e85 for 179 a gallon which was a big savings. Soon after I bought my truck I tried a couple tank fulls of e85 and was not happy with how my truck performed so I swore off since then and I didn't bite this time. Others seem to run the stuff exclusively and have real good results. And I know it is preferable to run either e85 or regular gas for extended periods of time but with the way my truck was running on it I didn't want to run it any longer.

 

Here is what the owners manual for the 2015 states:
If it does not have a yellow cap I would not use E85.

Fuel
For diesel engine vehicles, see
"Fuel for Diesel Engines" in the
Duramax diesel supplement.
Use of the recommended fuel is an
important part of the proper
maintenance of this vehicle. When
driving in the U.S., to help keep the
engine clean and maintain optimum
vehicle performance, we
recommend using TOP TIER
Detergent Gasolines. See
www.toptiergas.com for a list of TOP
TIER Detergent Gasolines.
If the vehicle has a yellow fuel cap,
E85 or FlexFuel can be used in the
vehicle. See E85 or FlexFuel on
page 9-65.
For all vehicles except those with
the 6.2L V8 engine, use regular
unleaded gasoline meeting ASTM
specification D4814 with a posted
octane rating of 87 or higher. Do not
use gasoline with an octane rating
below 87, as it may cause engine
damage and will lower fuel
economy.
If the vehicle has the 6.2L V8 engine
(VIN Code J), use premium
unleaded gasoline meeting ASTM
specification D4814 with a posted
octane rating of 91 or higher. If the
octane is less than 91, damage to
the engine may occur and may void
the vehicle warranty. If heavy
knocking is heard when using
gasoline rated at 91 octane or
higher, the engine needs service

E85 or FlexFuel
Vehicles with a yellow fuel cap can
use either unleaded gasoline or fuel
containing up to 85% ethanol (E85).
All other vehicles should use only
the unleaded gasoline as described
in Fuel on page 9-63.
The use of E85 or FlexFuel is
encouraged when the vehicle is
designed to use it. E85 or FlexFuel
is made from renewable sources.
To help locate fuel stations that
carry E85 or FlexFuel, the U.S.
Department of Energy has an
alternative fuels website. See
www.afdc.energy.gov/afdc/locator/
stations.
E85 or FlexFuel should meet ASTM
Specification D 5798 or CAN/
CGSB-3.512 in Canada.
Do not use the fuel if the ethanol
content is greater than 85%. Fuel
mixtures that do not meet ASTM or
CGSB specifications can affect
driveability and could cause the
malfunction indicator lamp to
come on.
For the 6.0L V8 engine, after
refueling, the vehicle calculates the
composition of the fuel. It is not
recommended to repeatedly switch
between fuels. If fuels are switched
frequently, add as much fuel as
possible and do not add less than
11 L (3 gal) when refueling. Drive at
least 11 km (7 mi) immediately after
refueling to allow the vehicle to
adapt to the change in ethanol
concentration.
Because E85 or FlexFuel has less
energy per liter (gallon) than
gasoline, the vehicle will need to be
refilled more often. See Filling the
Tank on page 9-66

 

Any update on if this can be upgraded at the dealership? I just bought a 2015 Silverado 5.3L and just found out its not e85 compatible. I didn't even think to check and see if it was before purchasing.

 

per dealer, no it is not an update/upgrade they can perform. I'm still waiting to hear from my GM source if such a modification can be completed. I was in the same boat, as I assumed all 2015 were E85 ready, just like the 2014 model. I have no clue why they would skip a $100 component on a $40,000+ vehicle!!! Makes no sense...

 

per dealer, no it is not an update/upgrade they can perform. I'm still waiting to hear from my GM source if such a modification can be completed. I was in the same boat, as I assumed all 2015 were E85 ready, just like the 2014 model. I have no clue why they would skip a $100 component on a $40,000+ vehicle!!! Makes no sense...

Yeah I don't get it either, its a big bummer.

 

Well, you could be like me. I have a yellow cap 2014 and have never seen E85 fuel in my life. Apparently I paid for an option I don't need. I also pay well over $4.00 a gallon.

 

Got a final answer from a GM engineer...and unfortunately it is not an upgrade that can be easily done.
Fuel Composition sensor, ECM programming and a few more parts are needed...long story short, next time I should look twice before sealing the deal....

 

GM pip5227 TSB I cut it down to the important stuff

Please note: There was a change during the production of 2015 Full-Size SUVs, and with the beginning production of 2015 Full-Size Light-Duty Pickups, shifting from a standard E85 capability on all of these vehicles equipped with the L83, 5.3L V8, to an optional E85 capability, requiring selection of E85 capability through vehicles equipped with RPO code FHS.

Note: Vehicles equipped with RPO FHO, E10 gasoline are certified for this fuel type and cannot be modified to allow use of E85 flex-fuel.

 

I am sure it can be switched over to E85 it just won't be done with the help of GM.

 

Well I have a 2012 2500 HD Sierra Flex Fuel with the yellow cap,, Truck does not have good fuel mileage, with E 85 I might get 8mpg,, I have been running 91 octane for the last four tanks and I am up to 10.5,, Last time I took it in for an oil change service (At the dealership) I mentioned the lousy mpgs,, manager said he'll check it out.
Thay did a complete fuel system check complete with a read out from there computer,, he said that it s in perfect condition but fuel flows and pressures are at the high end because its E85 and it uses more alcohol to keep the horse power up at the rated capacity. He asked if if I wanted him to turn it down to get better mpgs but loose HP? I asked if the ECM adjusts for the different fuels and he said that it does but its set up to be a Flex Fuel Vehicle and therefore is set up for E85, He also said 10+ mpg is good for that motor on premium fuel.. So I smiled and paid my bill...