Sounds normal to me

First off 75mph with an extra high trailer, gonna make a lot of head wind -- back the speed down some
The lift on the truck will also add some under carriage wind drag

 

I haven't got any real numbers towing yet, but I get around 17-18 mpg driving back and forth to work and mostly local driving. My truck is a 16 and bone stock. I've put about 22,000 miles on it since we've owned it, been to Florida twice (From N.E. Indiana) and have only added DEF to it 3 times, 2.5 gallon each time. Of course I know you will use more DEF when towing but that still seems a lot pulling just 7,000. Someone will be along soon with some better help then I have given you. Good luck!

 

I do not see a problem with your increase - it follows directly in line with your fuel usage and load... and in my opinion, moving 75MPH towing a trailer is hammering even if the truck does it with incredible ease. Simple rule: higher fuel usage and higher load = higher DEF usage.

 

Fuel sounds good, DEF maybe a little high.

 

Why are you running a banks at level three and monitoring fuel/def consumption?
Seems like you are asking to use more

 

DEF usage is controlled by programming and the sensors down stream of the SCR
maybe need to look at the health of the SCR catalyst and sensor readings to see if there is any problem

 

The reason I’m asking is a friend has the same exact truck and gets 18mpg when he is not towing and 16mpg when towing and does not use as much def as mine does. Also my 6.0 does the same trip at 14 mpg with the same trailer and weight but going faster. If I set the derringer at stock and drive locally it will only get 15 mpg and that’s not normal according to everyone I have talked with about this. The truck actually was worse without the derringer it would not even hit 14mpg local or highway.DEF consumption was a little high imo but not an expert at this . I’m thinking of deleting everything that I can to fix the problem. Not worried about emissions and don’t care to much about what the government says I should have on the truck . I deleted my 6.0 and it ran 1000 times better and was getting 20mpg instead of 10mpg so screw the emissions standards.

 

15 city with a 6.7L stock is certainly “normal” as is 8-10 mpg towing at 75 mph.

Hand calculate and don’t believe the hyperbolic bragging of others.

Best I can do is 19-20 empty on flat highway 15 city and 9-10 towing. (6.7L with 3.55 SRW )

 

Got it I can’t get over 15 on the highway. I’m getting 12.5 city and 14.6 highway. After hearing how this motor was that much better than a 6.0 I figured it would do better all the way around. I was thinking the DEF system had a problem because it was getting 14 towing then went into regen and the fuel mileage dropped to 10.4 mpg. The mileage empty was also better before so I assumed I had a problem. I know for a fact my buddy has the same truck and he gets the mileage I stated and he hasn’t used as much DEF on the same trip as I have. But I guess it is what it is and I will go back to using the 6.0 f350 .

As for your question heavy gd I have the derringer set in the middle as suggested and I’m not monitoring fuel and DEF consumption just comparing to my other f350 and a friends f350. I was always told how bad the 6.0 was but I never had any issues and it actually runs stronger and does better towing than my 6.7 . I’ve had these 1 ton diesel’s for years and never got this bad of fuel mileage from any one of them except this one. I have to be honest my 6.0 and 7.3 are probably the best motors I’ve had. My 6.0 would haul my back hoe around pretty dam well and still got decent fuel mileage.

 

Have you checked with the dealer to see if your vehicle was covered under the recent emissions recall? Mike is a 2016 and before the software update I used a lot more DEF than after the firmware upgrade. They also corrected a list of other issues I had like the fuel gauge being way off, before the free update I had 6 gallons of fuel left when low fuel light came on, after the update its now closer to 1.5 gallons.

 

SSgt, comparing yourself to others is the thief of joy.

 

Heavy gd I just like to make sure my equipment is running the way it should and if not then it’s gotta be fixed. Just don’t want any issues coming at me when I’m not expecting. I also thought these new trucks were better. I haven’t used this truck for pulling my stuff until now but I guess I will stay with the older stuff they run better and stronger. The factor is at $6.05 a gallon in the north east you have to keep your equipment at its best or you aren’t making money just throwing it out the window

 

I'm in agreement with @FordDoctor . I had an issue after an update where my consumption went up significantly. It has since leveled back out as they said it would. What I did learn from the dealer is that DEF consumption can be as much as 2-3% of your fuel. Towing my toy hauler to Homestead FL and back (1055 miles each way), would chew through near a tank of DEF. That's averaging 11-12 mpg and staying 70 mph or under.

 

How is your mileage without the toy hauler? I can only get 15.6 at best without my trailer and still uses the same amount of DEF running the speed limit on the highway total trip was 2010 miles and 5gals. Of DEF . Trip down 75 mph loaded 10.6 and 2.5 gals of DEF. Trip back was no trailer and I slowed down to see if I could get better results. Derringer was set to stock setting on the road back and best was 15.6 mpg which is worse than 6.0 with 3.73 gears and doing a lot faster. My friend has the same truck 19 f350 lariat premium 4x4 with 3.51 electric limited slip. He gets 18 mpg unloaded and 16 mpg with the trailer loaded. Just doesn’t seem right and if I have a problem starting I just want to catch it before it gets worse. If no problem then I guess the 05 will stay as the tow vehicle.

 

Mileage depends a lot on driving habits

Tires and if you have a lift also makes a diff

 

factory size tire and no lift . No matter how I drive this thing it is getting the same as I stated since it was in the last regen. the truck was doing better before the regen I was getting 13MPG before the last regen while towing now I'm getting 10.6 so I am assuming something is going on with the truck that is why I am asking so I don't have a big problem on my hands.

 

Where are you? When I lived in the Blue Ridge the best I saw per tank was 14. Now in the flatlands I see 17/ tank empty. Highway in the FL- SC route I managed 22 in a tank. But that was empty, stock height, factory rock hard crappy Michelin tires under 70 the whole way. I think the real # was 21.7

 

Banks was uninstalled and no difference. I am in upstate NY and traveling down to the lake Lanier area of Georgia. I spoke to banks and rebooted the derringer also if that doesn’t do anything they are getting that back and then I think I’m going to look at my fuel filter’s maybe I got a bad tank of fuel. If nothing from that I will just go back to using my old work horse the 05 6.0 350.

 

Yup. Winter fuel and hills. 15 sounds right.
Edit- C&D real world testing of the 6.7 found similar results as what you are getting.

Vehicles Tested with the Worst Highway MPG

A Jeep Gladiator Mojave returned the same highway fuel economy as a Ford F-250 Super Duty.

www.caranddriver.com

.

 

Not only winter fuel but garbage fuel . That fuel isn’t half of what it used to be. I think my problem is an update that ford did on the truck when it went in for service.

 

Well, that's true from what I have seen. One station near me (Shell) is selling a non Shell diesel for about 30 cents lower than anyone else. I consistently get worse MPG using that fuel over using Shell branded or Sheetz diesel. Don't know the difference. Maybe it's the Cetane? I have read that typically Cetane in my area is 45- 47. Maybe that fuel is the bare minimum 40?
I've also witnessed with my own truck that my economy tanked (pun intended) when they did the NOX sensor update last year. It came back, but the first tank or two really worried me. Even got a CEL for cylinder contribution imbalance but it went away.

 

So your friend says he gets 16 MPG towing the same tall 7k trailer you tow? I know these new 10 speeds get better fuel economy, but I don't buy that math... Your numbers seem reasonable for how you drive coupled with the winter blend you're burning.

 

I know on my truck lower mpg can be a sign of a boost leak or a dirty MAP sensor. Usually just requires tightening a clamp or two and taking some electronic contact cleaner and a paint brush to the MAP sensor.

 

I drive the truck in Georgia for a week using the diesel fuel that isn’t cut with kero (winter blend) and mileage didn’t come up . I’m thinking either the update that the dealer did or I have a problem with the regen system because all this started after a regen on the highway. No trailer and empty driving like grandpa can’t get past 14.6 without the derringer hooked up on the highway or city driving. I’m hoping that this problem is just crummy fuel and I can change the fuel filters and start over.

 

Like I said earlier if my mileage doesn’t come back it is what it is . Hopefully the DEF consumption doesn’t get any worse .Just sucks digging deeper into my pockets for no reason other than having douchebags for politicians that want to make us go to electric junk . Hopefully a fuel filter change will help but I can always go back to the work horse for towing.

 

My 2022 F-350, Lariat, 4x4, SRW, LB, 3.31 gears, electronic locking differential, gets 20 hwy @74 mph (empty) 15 mpg city and towing my 30’ fifth wheel @65 mph (that’s the maximum rated speed for the tires on the 5th wheel). The truck is completely stock and has 4,400 miles on it.

Towing the same 5th wheel and @ the same speed with the 2016 F-350, King Ranch, 4x4, LB, 3.73 gears, electronic locking differential, the best mileage I could get was 10mpg, 15 mpg empty hwy and 13-14 city. I traded this truck in for my special order 2022 F-350 Lariat.

 

My first PS was a 14 F250 with 3.55's. Not towing, highway mileage was in the 20.5 to 21 running 65-70, in town 14.5 to 15. Went through a jug of DEF about every 2500 miles. Towing a 37 foot, 12,000 pound 5th wheel highway mileage dropped to about 11 to 11.5. Went through a jug of DEF every 1000 miles. Truck pulled like a champ.

Sold that truck to a buddy, bought a 19 350 SRW with 3.55's. Best I ever saw highway was around 18. Didn't matter about driving style or speed. 60 got no better than 70. Pulling the same 5th wheel, got about 10. Used DEF twice as fast.

Upgraded 5th wheel to a 43 foot, 16,000 pound. Mileage dropped to 8.5 to 9 at best. Stayed in 4th or 5th the majority of the time. Drank DEF almost as fast as diesel. Had to add a jug of DEF every 500-600 miles. Got real tired of that REAL fast.

Traded that in on a 20 F350 DRW with 4.10 (10 speed trans). Highway mileage not towing, running 65 to 70, 19 all day every day. Towing the same 43 foot 5th wheel, 11 to 11.5 and honestly DEF usage is hardly any different. Stays in 10th most of the time except going downhill.

Say what they want, there is something just not right with those 17-19 trucks. Maybe the upgrades to the engine needed the 10 speed to actually perform their best.