I know this subject has been beaten to death and then some, but every time I read about someone getting 18-20 mpg with their similar truck...and I go to the filling station and get13-15 mpg...I wonder what the deal is. Obviously, I don't race it, but, I don't baby it either. I've put a lot of time and money into increasing my mileage...new ip, new injectors, new return kit, electric lift pump, new brake system, new fuel tank pick ups, after market fuel filter, keep clean air filter, new rear fuel tank...it doesn't make any difference if I use a diesel additive or not...I wonder if it could be something like valve adjustment or tweaking the timing, which I'm hesitant to jack with since the truck works pretty well. Does anyone know anything they've tried that dramatically effected their fuel mileage? I'm about 6k lbs, E40D with 40k on a rebuild., 3.73 rear end, 2wd, michelins with 80 psi...I keep deciding to ignore the mileage thing and get on with my life, until one of you comment on your rig getting 18-22 mpg uphill 7% grade at 80mph pulling 10k against a headwind...then I start to wonder...what am I doing wrong???

 

I get about 11mpg running down the interstate with an empty bed.
201K on the ticker 4X4 C6 and 4.10 gears.

 

some 3.55s or 3.08s would help your mileage some......

 

you said you havent touched yuo timing eithr, when I got my truck I was getting 9mpg and had to advance my timing alot and started to get 13-14mpg, maybe you should get your truck pulse timed, I will be doing the same once I get a new injection pump

 

You're believing ridiculous internet claims. Fuel mileage is lied & exaggerated more than any other thing, except maybe how good looking she was & how big that bass was.

3.73's? Did you manage to find a factory rear end with them? Or you planning on rebuilding your axle? If so, have you priced a ring & pinion for our trucks? The cheapest set I could find (with a Chingchong rebuild kit) is almost $500. Expect to spent well over $700 for name brand gears & Timken rebuild kit.

 

Oh...I had a brain fart...my truck has a 3.55 rear end. So, mostly 13 and sometimes up to 15 mpg is within the envelope and I'll quit agonizing about my poor mileage and just enjoy the ride...which I really do. I like my truck. My wife doesn't, but, so what. She likes my BMW K1200LT.

 

Before I blew mine up I got 17- 18 mpg consistantly for over 10 years. I dont think Im lying about that,or anyone else here is either.

 

Excellent choice in 2wheeled transport. Savor the 45-50mpg you get out of it, and just enjoy driving the truck because, well, these trucks are just awesomeness.

 

I said it is probably the most heavily exaggerated claim on the Internet. It is also a very "user specific" condition. When do you stop filling your tank? Stop at the first cutoff or tamp that extra 2 gallons down in there? Those 2 gallons make a definite ding in what your overall mpg's are. How heavy is your skinny pedal foot? You cruise at 58mph, no matter what, driving highway, and your mileage is going to be higher than driving in town, or driving at 82mph, no matter what. How heavy do you load your truck? Deer slayer bumpers or factory? See how easy it is to distort your mileage vs someone else's?

And once ULSD came on the scene, mileage has dropped a couple of MPG in my experience.

 

David85 has low gears but he gets like 24mpg with his truck, and like Rick there are many people who are getting mileage same as his.

I'm thinking you may have timing issues.
My truck is alot more heavy duty setup than your truck and I get your mpg

bad timing can be a night and day difference with these trucks (first thing I learned when I got this truck) does it smoke at all once up to normal engine temperature? my truck had a grey/blueish haze that was gone when I advanced my pump.

Also this may be unlikely but have you checked to see if you might have a dragging drum in the rear or disc brake in the front? swollen brake lines too. 20yrs of hydraulic fluid in rubber could wear things out if you havent changed them haha I need to do mine soon

 

i was getting 16.7 average all day long in my truck pulling a car trailer. loaded one way, unloaded back. i have a zf5, 4.10's with 37's at the time. the turbo helps big time, driving it easy helps more. keeping the speed low and taking your time on take-offs are key. i never went over 55-60 in o.d. and the drive included 20 miles of 6 degree inclines and drops. when i went to the 42's same everything else but added intercooler i dropped to 13.5mpg loaded. not sure her empty mpg because i hardly drive it without a trailer. oh, and cruise control helps big time too. (wish mine worked!)

 

going from n/a to turbo i went from 12mpg to 16.7. my next door neighbor went in his f-superduty tow truck went from 9 to 12mpg. hes got a ton of blow-by though. tired engines cant be helped nearly as much as a lower mileage truck

 

So, I'll try advancing my timing a little, try to find a turbo I can afford and see what that does for me. You did notice I have all new brakes, hydroboost and brake lines, right? I had a suburban with a 6.2 and it got 20mpg no matter what...Of course, it didn't pull a heavy load very well...but I could load up the rear with fire wood and it was like nothing was there![until I started down or uphill...]

 

you need to keep fluids changed.
this means the front/rear axles/trans/engine.
old broken down lube won't do you any good.
(use synthetic everywhere you can afford it.)


when checking mileage.it's important to check tanks back to back.this eliminates any "guessing" done at the pump.
take peoples claims of 20+ mpg "peaks" and throw them out the window.this means nothing.
(iv no doubt these rigs can hit that on average out on the flat,with stock beds.especially on long runs.)


what size tires do you run,and what speed do you travel most often?

my mileage to date is:
15.25 @ 27 tanks.(most of them being consecutive and like all of them just before the DRW conversion.)

my set up and mods:
https://www.ford-trucks.com/forums/g...F250HDXLT.html


my mileage info:
Ford Truck Enthusiasts Forums - Garage Fuel Economy
(chipper truck.)

timing needs to be checked and set every 30k miles (roughly) for best performance and fuel economy.
it certainly needs to be set after new ip and injectors.

you need to keep the air filter clean,clean,and cleaner!
as well as the exhaust open.an old plugged up stock muffler = doom and gloom for performance and economy.

if you have changed tire size,it is extremely important that you recalibrate your speedo/odo,or your calculations are worthless.

i shouldn't be able to touch your mileage.
im DRW,not on flat ground like Texas,carry heavy loads often,and have a large frontal wind catching bed.

the way you drive means everything.
take off like most people do today,and its not the best.drive over 55 mph and it also suffers.

a "beater with a heater" isn't going to be a fair comparison if your running a/c all the time out there in Texas either.
check my records when i use a/c.a worn out pump.....possibly? but whatever the case,it hurts(not that i care much when im working and its hot.)

more fuel economy tips to follow:
https://www.ford-trucks.com/forums/9...ing-25mpg.html

 

When I bought my truck, the seller made claims of "up-to..." "20-ish mpg". I kept close track for several months and found that (unloaded) it ran at 17 mpg almost no matter what... 55 mph or 75 mph didn't seem to matter. Dirt road travel 25-35 mph, some 4x4 was the same... 17 mpg. Pulling a trailer up hills it dropped drastically (10-ish???) which I expected. The truck has a Gear Vendor Under/Overdrive gear splitter to help out with the 4.10 gears, so the 17 mpg was with the OD on... a 22% upshift in gear ratio. With the OD off, it ran at 15 mpg all day long, so the gear ratio is definitely important! It's not the 20 mpg everyone "expects" from a diesel pick-up, but for a 24 year-old F350 4X4 crew cab long-bed I am ~very pleased with the fuel efficiency.

1986 F350 4X4 Crew Cab
6.9L IDI non-turbo
4.10 gears, T19 4 speed, Gear Vendor Under/Overdrive, 30 inch tires