Interesting fuel mileage with 6.7

[Timsdually]

Not me.
Last truck I had that was filled to the tippy top ruined an emission vapor part and cost over $200 to fix. Most vehicles even have a warning, Do Not Top Off When Filling Tank.
As soon as auto fill clicks off on the pump that's it for me. Done.

 

[jejb]

Not me.
Last truck I had that was filled to the tippy top ruined an emission vapor part and cost over $200 to fix. Most vehicles even have a warning, Do Not Top Off When Filling Tank.
As soon as auto fill clicks off on the pump that's it for me. Done.

Ram diesels, which are the subject here, don't have that issue.

 

[KoboldTaco]

I always enjoy these threads but my preference is to drive the truck, and when I get to 1/4 tank left I start searching for a gas station, and put more gas in the truck. Mileage is what mileage is - a combination of tire pressure, wind speed, wind and driving direction, driving habits, and I’m sure another 1/2 dozen influencing factors on overall MPG.

Having said that in a cheeky way, I don’t know why I always have the MPG meter up on the EVIC screen. It does not change how I drive, but a morbid curiosity about just how efficient my 6.7 is.

I’m on the fence about a larger gas tank - especially when towing it would be nice to have an unladen range with a 55-gallon unit; sadly with the trade-off of a reduced payload. That hunk of plastic is more expensive than I’m willing to spend right now.

 

[mtofell]

Slight changes in grade are almost impossible to detect with the naked eye and can have reasonably big impacts on MPGs. Wind can also change and have a big impact. I've noticed a similar thing with my Hemi when watching the MPG meter. It seems to change for no reason and I've always just figured it's slightly different conditions.

 

[68PowerWagon]

Slight changes in grade are almost impossible to detect with the naked eye and can have reasonably big impacts on MPGs. Wind can also change and have a big impact. I've noticed a similar thing with my Hemi when watching the MPG meter. It seems to change for no reason and I've always just figured it's slightly different conditions.

Yes I keep most of that in the back of my mind while driving. These HD's gas or diesel can easily lose 2mpg with a decent head wind. I use my mileage as a tool. Not only to keep my foot out of it, but generally if you get a sudden change in mpg & none of the above factors apply, it usually means there is an issue going on with the engine. Not knowing enough about this engine yet, it just set off alarms in my head when it fluctuated that much. I have noticed with this engine that the faster you go above 60 it drastically drops off. It always dropped off with my gassers as well but not as drastic as this beast.

 

[Hydraplane]

Yes I keep most of that in the back of my mind while driving. These HD's gas or diesel can easily lose 2mpg with a decent head wind. I use my mileage as a tool. Not only to keep my foot out of it, but generally if you get a sudden change in mpg & none of the above factors apply, it usually means there is an issue going on with the engine. Not knowing enough about this engine yet, it just set off alarms in my head when it fluctuated that much. I have noticed with this engine that the faster you go above 60 it drastically drops off. It always dropped off with my gassers as well but not as drastic as this beast.

I too am new to owning a diesel. I just bought a new '22 2500 Tradesman 4x4 with some add ons. I'm getting ready to just google some of my questions...

 

[jejb]

I too am new to owning a diesel. I just bought a new '22 2500 Tradesman 4x4 with some add ons. I'm getting ready to just google some of my questions...

Might want to change your info under your name. Says you have an 18 Ram, 6.4

 

[Hydraplane]

Might want to change your info under your name. Says you have an 18 Ram, 6.4

Thanks! And the pic too!

 

[ibike]

Not me. I take my time and fill up to the tippy-top each time I fill. It's almost always much more accurate than the lie-o-meter on the dash. On long trips, I've consistently gotten the same mpg fill after fill, driving on flat midwestern highways, while the EVIC indicated 2mpg higher. I take the EVIC mpg reading as just a very rough indicator. The only time it is close is when I'm hauling my bass boat over long distances. I reset the trip computer at each fill.

I’ve heard twice now that cramming as much gas in till you see it in the neck it’ll back flow into all the evap/emission equipment and cause problems in them. It makes a lot of sense to me. Shutting the gas off after first click off is a best practice.

 

[jejb]

I’ve heard twice now that cramming as much gas in till you see it in the neck it’ll back flow into all the evap/emission equipment and cause problems in them. It makes a lot of sense to me. Shutting the gas off after first click off is a best practice.

That may be a gas truck thing.

 

[ibike]

That may be a gas truck thing.

For sure.. I’m not familiar with diesel emissions. Do they have an evap canister? That’s what I understand gets inadvertently filled when you fill to the top of the neck.

 

[jejb]

For sure.. I’m not familiar with diesel emissions. Do they have an evap canister? That’s what I understand gets inadvertently filled when you fill to the top of the neck.

I have no idea, but I've not heard of this being an issue with the Cummins.

 

[06 Dodge]

I have no idea, but I've not heard of this being an issue with the Cummins.

I top off (one gallon) in my 2022 and have done so from day one, so far no problems, in my old 06 when traveling would top off 2 gallons at every fill and in 15 years of doing so I had no problems.

 

[68PowerWagon]

Yeah, I am the same way... when I know fuel is going up, I cram as much as I can in there before they raise the price. Don't believe I have ever had any issues.