Hello from France / Need help on my 2018 DENALI

lolpops · October 5, 2019

Hi !

I'm Laurent from France (so excuse me formy poor english) and I've just bought a GMC SIERRA DENALI 2018 with V8 6.2L and BVA 8 speed. It's all new, I got it with about 70kms (near 45 milles...)

In France you have lot of taxes and we've got E10/SP95 at about 1,5€/L, SP98 at 1,6€/L and now E85 at 0,6€/L and when you use it for your firm it cost 0,5€/L

The seller told me It's a flexfuel so I can put E85

When I took the truck, the tank was full, I put E85 a first time, no problem, but the second time, the truck had about 950kms, the "check engine" light goes on. I called the seller and he told me "that's not a problem (???), it's the E85, we have to program the engine because the E85 in France is not the same that in US" (???)

So I don't really trust him ! I saw that truck made for run with E85 had a yellow sticker in the tank door, mine don't have, but a sticker, you can put one as easy as you can remove it...

I try to send a mail at GMC, but no answer, in the chat on the website they told me they only check the US cars...

How can I check if my truck is made to run with E85 or not ?

With the VIN number ?

I saw that they are some codes in a box, where can I find them and where can I find what they mean ?

Thanks a lot for your answers !!!

Regards

Laurent

SARNCAN · October 5, 2019

Hi !
I'm Laurent from France (so excuse me formy poor english) and I've just bought a GMC SIERRA DENALI 2018 with V8 6.2L and BVA 8 speed. It's all new, I got it with about 70kms (near 45 milles...)
In France you have lot of taxes and we've got E10/SP95 at about 1,5€/L, SP98 at 1,6€/L and now E85 at 0,6€/L and when you use it for your firm it cost 0,5€/L
The seller told me It's a flexfuel so I can put E85
When I took the truck, the tank was full, I put E85 a first time, no problem, but the second time, the truck had about 950kms, the "check engine" light goes on. I called the seller and he told me "that's not a problem (???), it's the E85, we have to program the engine because the E85 in France is not the same that in US" (???)
So I don't really trust him ! I saw that truck made for run with E85 had a yellow sticker in the tank door, mine don't have, but a sticker, you can put one as easy as you can remove it...
I try to send a mail at GMC, but no answer, in the chat on the website they told me they only check the US cars...
How can I check if my truck is made to run with E85 or not ?
With the VIN number ?
I saw that they are some codes in a box, where can I find them and where can I find what they mean ?

Thanks a lot for your answers !!!

Regards

Laurent

I would say E85 is very low and not suitable for the Denali, and you should go higher.

The codes are now QR code you scan with your smart phone camera, it is between driver’s door and rear left door

SierraHD17 · October 5, 2019

The 6.2s are not programmed for e85 from the factory nor do they have the alcohol sensor in the fuel line for it. If you have the sensor added in the fuel line and have it tuned they run e85 just fine. Otherwise you should be running only premium gas.

Your truck is no more of an export than one I buy here in Canada so it will be the same thing.

Edited October 5, 2019 by SierraHD17

CamGTP · October 5, 2019

E85 has a higher octane rating that premium fuel. It just requires 30% more of it because of the type of fuel it is.

The problem you have is that trucks after 2015 and for sure anything made in 2017 and 2018 are not factory flex fuel trucks. If the gas cap is not yellow and there is no flex fuel sticker in the fuel door, the trucks is not made to run flex fuel.

You can even crawl under the truck and follow the fuel line on the frame rail. There should be a sensor plumbed in if there was one. You will also likely find the flex fuel harness that is wire clipped to the cross member just sitting there with a dummy plug in it to keep dirt out.

It would require a sensor be installed and a custom software tune to enable the flex fuel feature. That can get very expensive if nobody near your location can do that service.

lolpops · October 6, 2019

Thanks guys, the cap is black...

I'll try to scan the QR code tomorrow when I'll get the truck back...

SARNCAN · October 6, 2019

Thanks guys, the cap is black...
I'll try to scan the QR code tomorrow when I'll get the truck back...

Scanning the QR code will give you part of the list, if you need the full list then ask the dealer (service) to print it for you from their GM website (GM Global Connect) for free. Full details of the car is there including previous service and warranty

lolpops · October 7, 2019

In France there is no official GMC dealer so I can't ask that

Thanks

L86 All Terrain · October 7, 2019

The 2015+ 6.2L CAN NOT run E85 as it is set up from the factory.

You CAN make it run on E85, but you will need 8 new E85 capable fuel injectors, and a custom tune for the ECU.

This route will cost you thousands of dollars, I would expect it to take 5+ years to pay off the cost of the upgrades in fuel savings from utilizing E85. Additionally, it may be difficult to find someone in France that can reliably tune modern Gen5 GM LT V8's.

It would be cheaper, safer and easier to purchase SP98. These trucks can run on your blended E10/SP90, but the ECU will retard the timing to prevent pre-detonation of the cylinders and you will lose some power, but it wont hurt the engine.

Your best bet is to forget about E85 unless you are going to mod the truck for performance anyway.

CamGTP · October 7, 2019

I'm running E85 on stock non flex fuel injectors, no problems here.

lolpops · October 8, 2019

14 hours ago, L86 All Terrain said:

The 2015+ 6.2L CAN NOT run E85 as it is set up from the factory.

You CAN make it run on E85, but you will need 8 new E85 capable fuel injectors, and a custom tune for the ECU.

This route will cost you thousands of dollars, I would expect it to take 5+ years to pay off the cost of the upgrades in fuel savings from utilizing E85. Additionally, it may be difficult to find someone in France that can reliably tune modern Gen5 GM LT V8's.

It would be cheaper, safer and easier to purchase SP98. These trucks can run on your blended E10/SP90, but the ECU will retard the timing to prevent pre-detonation of the cylinders and you will lose some power, but it wont hurt the engine.

Your best bet is to forget about E85 unless you are going to mod the truck for performance anyway.

Well, I have just bought the truck and I bought it to run with E85, the seller told me "it's flexfuel" and wrote it every where on the bill, etc...

Now some one are telling me V8 6.2L L86 can run E85, every things is ok for that, injectors, etc... It's just that E85 program is not in the ECU so the seller as just to program it correctly and for some one just has to add a sensor somewhere (I don't know !), mine has been built in Mexico... The guy told me that 2019 V8 6.2L CAN NOT run E85 because of new injectors, etc... but up to 2018 are all ok, 2015 to 2018 ?

Some other, like you, tell me it's not built to run with E85, running with E85 will cause damage on the motor...

So ? Who tells right ?

Now, in France, professionel sellers can't say 'it's flexfuel" to sell trucks that are not, they can have big problems...

So now I just need to know how I can join GMC (or a GMC official dealer) and how they can attest me my car is ok or not to run with E85, with or without reprogramming ECU, adding a sensor, etc...

If I have to resort a lawyer, I can come and say "my truck doesn't run E85, it's L86 ALL TERRAIN that has told me" !!! I need official documents

Thanks

Edited October 8, 2019 by lolpops

L86 All Terrain · October 8, 2019

7 hours ago, lolpops said:

Well, I have just bought the truck and I bought it to run with E85, the seller told me "it's flexfuel" and wrote it every where on the bill, etc...

Now some one are telling me V8 6.2L L86 can run E85, every things is ok for that, injectors, etc... It's just that E85 program is not in the ECU so the seller as just to program it correctly and for some one just has to add a sensor somewhere (I don't know !), mine has been built in Mexico... The guy told me that 2019 V8 6.2L CAN NOT run E85 because of new injectors, etc... but up to 2018 are all ok, 2015 to 2018 ?

Some other, like you, tell me it's not built to run with E85, running with E85 will cause damage on the motor...

So ? Who tells right ?

Now, in France, professionel sellers can't say 'it's flexfuel" to sell trucks that are not, they can have big problems...

So now I just need to know how I can join GMC (or a GMC official dealer) and how they can attest me my car is ok or not to run with E85, with or without reprogramming ECU, adding a sensor, etc...

If I have to resort a lawyer, I can come and say "my truck doesn't run E85, it's L86 ALL TERRAIN that has told me" !!! I need official documents

Thanks

Just read your manual and the sticker in the fuel cap door, the owner's manual will say NO E85, and your fuel cap will say "91octane/premium recommended". The 5.3L engine is a Flex Fuel engine. The only 6.2L to be Flex Fuel capable are the 2009-2013 6.2L (Gen IV small block, LS Family) and the 2014 6.2L (Gen V small block LT family). The 2015+ L86 6.2L are not Flex Fuel capable. You can add the sensors and tune, but I still think you need new injectors but I could be wrong on the injectors. Either way, it's an expensive road to go down and you will take a very long time to make your money back. Your better off just paying for the premium gas. There are no advantages to E85 in a daily driver except price.

Your truck is very rare in France I would assume, maybe you want to sell it for a handsome profit and buy a 5.3L flex fuel Denali if you are set on E85. I can imagine finding someone who can tune your truck in France is like looking for a needle in a haystack.

wforrest08 · October 8, 2019

Your truck did not leave the assembly line capable of running E85 period end of story. To run E85 someone would have to added a fuel sensor either factory or aftermarket. So your best bet is to go out and physically stick your head under your truck and see if there is a fuel sensor in the fuel line.

Heres the RPO codes not that it matters

RPO codes

FHO: Non Flex

FHS: Flex Fuel

sensor is located on the drives side of the frame in the fuel line with quick connects if you have it if you don’t it’s just 3 mounting holes and a red connector with 3 wires (white black purple if I remember right) not hooked to anything.

Here is several threads for your reading.

Stock sensor picture on page 5 of this thread

This is what an aftermarket sensor will look like under the truck

http://www.cjtunes.com/store/flex-fuel-conversions/14plus-gm-truckssuv-flex-fuel-conversion/

lolpops · October 8, 2019

Thanks,

I will check RPO codes if I can find them tomorrow if they bring me the truck back (they should have done it wednesday and there is two problems staying on the truck but it's another story...)

I've just bought a truck at 80k US$, it's not to go under and check anything

I would have liked GMC to answer to my only question but it seems to be so difficult with them

One thing is sur it's my first and last GMC, I don't want to give money to some one who don't care about their customers any more...

truckguy82 · October 8, 2019

48 minutes ago, lolpops said:

Thanks,

I will check RPO codes if I can find them tomorrow if they bring me the truck back (they should have done it wednesday and there is two problems staying on the truck but it's another story...)

I've just bought a truck at 80k US$, it's not to go under and check anything

I would have liked GMC to answer to my only question but it seems to be so difficult with them

One thing is sur it's my first and last GMC, I don't want to give money to some one who don't care about their customers any more...

You don’t need to check rpo codes. There is no such thing as a 6.2L that can accept e85 from the factory.

If you want to run e85 you have to convert it. Thankfully, compared to a lot of other vehicles, it is pretty easy to convert. You can find out how to convert with the info above, in the post with the links.

Edited October 8, 2019 by truckguy82