6.4L Power Stroke Engine and DrivetrainDiscussion of the 6.4L Power Stroke diesel engine and drivetrain in the 2008 Super-Duty trucks. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 6.4L Power Stroke engine.
I just came back from a "380 gallons of Diesel" trip. Dallas to Northern California and back. We pulled our 8000lb boat and loaded the back of the truck with camping gear. My mileage there and back stunk. 9.1MPG average, hand calculated the whole way at every fuel stop. I filled the tank right to the top of the fuel fill hose every time. I carried two extra 5gal cans of fuel just to ensure I never ran out. (The fuel tank is WAY too small!)
18 Fill ups (I'm not including the last fill up as I also put the fuel in from the two cans).
380.046 gal of fuel
3450.1 miles traveled
9.1 avg mpg
Longest distance between fueling - 283.9 miles, 29.588 gal, 9.6 mpg.
Average speed 70 to 75mph (depending on state).
Odd thing since I have gotten back. My mileage seems to have improved. In my one tank I have used since returning, I have gotten 19.1 mpg (mostly highway, some stoplights).
356.1 miles
18.64 gal
19.1 mpg
The mpg computer registers and holds as much as 23.5mpg as I reset it while traveling on the highway, curious to see what it would say.
Has anyone else experienced this?
Is it due to the engine oil being broken in (7000 miles now on this oil), or the engine more broken in (around 28000 miles on the truck)?
Is this possible? Is it real and will it stay that way now?
I am curious how many miles this next tank will produce.
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2003 F-350 6.0L CC/SRW/SB 3.73 Auto..
Edge Juice Platinum w/ Attitude just to monitor
Xcal2 w/ID tow w/JAKE,Street,Extreme Street
K&N FIPK kit
NO TURBO or ELECTRIC PROBLEMS
3 injectors, 1 set of head gaskets @ 95,000 miles
rebuilt tranny, plates and soleniods
built 03/27/03
H2Oman
I read someplace that until the PSD get's a 'real' work out, fuel mileage won't improve. Others have had the same experience as yours - put some weight behind it, make it work for a living and POOF the engine is officially broken in and the mileage improves. What a hoot. I guess that's one of the differences between diesel and gas.
Keep us posted if you validate.
I have found my mileage has improved with more ummm mileage on the truck. As stated were you towing with your increased fuel economy.
Silly thing with this truck is that I have found is that if you are doing the speed limit on the highway and don't deviate from it (even just a little bit) my economy is amazing. 110 kph in Canada here and I can get about 19.5-20 mpg.
I have found my mileage has improved with more ummm mileage on the truck. As stated were you towing with your increased fuel economy.
Silly thing with this truck is that I have found is that if you are doing the speed limit on the highway and don't deviate from it (even just a little bit) my economy is amazing. 110 kph in Canada here and I can get about 19.5-20 mpg.
I was going to respond sooner with the exact same response. I keep a fuel log. When I bought the truck (new), it was getting around 12 MPG. 6k miles later, I'm getting around 14 MPG. No changes in driving habits, and I usually ride with the big rigs.
Owner of Defiant Truck Accessories says that these trucks are "programmed" to get better mileage over time. A programmed break-in, I suppose. I'm inclined to agree, because it does seem to get better and better with each tank.
I was going to respond sooner with the exact same response. I keep a fuel log. When I bought the truck (new), it was getting around 12 MPG. 6k miles later, I'm getting around 14 MPG. No changes in driving habits, and I usually ride with the big rigs.
Owner of Defiant Truck Accessories says that these trucks are "programmed" to get better mileage over time. A programmed break-in, I suppose. I'm inclined to agree, because it does seem to get better and better with each tank.
Do you notice a difference in mileage with whatever speed you're cruising at?
Obviously there is going to be a difference but I notice a SIGNIFICANT difference between 110 kph and 120 kph (68 mph-75mph). Not anything like being able to watch the needle on the gauge drop or anything.
I just did a 3,000 mile round trip from San Diego to Yellowstone National Park pulling my 10k fiver, used 296 gallons which equals 10.1 MPG. Climbed a lot of mountains, pulling the fiver over 8,000 feet four times or more. I drove a bit slower, 60 MPH in California (Heavy CHP activity) and 65 MPH out of CA, trailer tires are only rated to 65 MPH and with diesel on this trip averaging me $4.80 per gallon, I decided to go for fuel economy instead of time.
Don't know the particulars of your truck, but mine are in the sig below.
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2008 6.4L F350 King Ranch, Crew Cab, Long Box, 4X4, Dual Rear Wheels, 4.10 rear-end
Don't forget we are now running summer blend fuel, so by now the stations have pretty much turned over any winter blend in the tanks. You usually see a drop in MPG with winter blends.
Do you notice a difference in mileage with whatever speed you're cruising at?
Obviously there is going to be a difference but I notice a SIGNIFICANT difference between 110 kph and 120 kph (68 mph-75mph). Not anything like being able to watch the needle on the gauge drop or anything.
Most definitely. As long as I keep it between 55 mph and 62 mph, I can usually maintain real close to 14 mpg; I can usually get better if I ride close enough to a big rig so that he breaks the wind for me. Don't do it enough to tell you, but am certain that anything faster than 65 mph is a significant drop in efficiency.
BTW, my truck is bone stock. No intake mods, chips, etc. 100% stock.
mine did the same thing after towing a long distance. but after a short time mack to the same ole mileage. Guessing while towing it is the same as a regen with the much higher power settings, and egt (passive regen)
hey all ive been reading the posts on here for quite sometime, however i never registered until now after finally purchasing an 08 ford F250 CC SB ,
the truck now is sitting at 14,300 miles (bought from US) i live in canada...i have a 6inch fabtech lift with 37 inch toyo open country tires, unloaded between driving on the highway and rural roads ive been averaging consistent 16.5-18.0 mpg, hand calculated in liters to US gallons...not imperial gallons. Regen is still in place, no programmer, i due however run the ford fuel additive. As the millage has increased the fuel millage has also increased. Adding the increased tire size has not hurt the millage whatsoever in my driving conditions, if i drove in stop and go traffic im sure that would be different. As someone else had mentioned keeping the speed at about 100km or just over 60mph makes all the difference, (my speedo is calibrated for 35inch tires so its slightly out) i know people with F450s who are not nearly as happy as myself, and i also dont do much city driving, but for what i use the truck for im extreamly happy and cant complain about the millage at all....only problem ive had was a radiator replaced and its never leaked since
Break-in makes a huge difference. I just completed a run from Woodbridge CA to Duncan BC, Canada to pic up a car (carried a front end dolly in the bed of the truck up, towed a car (Jag XKE) on the dolly back...total of around 2000 miles. The truck started with about 12000 on the clock and was getting +/- 17 MPG mixed city town.On the way up to Canada driving easy with a cargo of prolly 800 lbs of dolly and tools @ 65 MPH the overhead showed 21.5 MPG. Driving around Vancouver Island without the stuff in the bed it showed 22-22.5. With the Jag on the tow dolly it showed 18-19.5 on the trip back.
I hand calc'd the entire trip and it came to 19.3 MPG...I'm getting happier as the engine breaks in.
Point is.....whatever ya got (6.4, 6.0 5.9, 6.7, 7.3 etc) you will get a big junp in fuel economy at some point when break-in occurs
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'06 Ram 3500 4X4 QC CTD 6sp LB
'01 F350 PSD 4X4 6sp Crew Cab (sold)
'68 F250 C/S 4X2 C6/428PI
Stidham 24' enclosed car hauler
Bunch of big old cars
In theory, practice and theory are the same.
In practice, they are not.
2008 F350 DRW crew cab, FX4 package. S&B cold air intake. FS 2500 by-pass oil filter, B&W Turn over hitch.
Linear Mode
