I have a 2003 7.3L F250 4x4 that get 10 MPG hand calculated no matter how I drive it. Only had the truck about a month now and am concerned something is not right.
Drove the first tank like I stole it (man these things are fun!) 10 MPG
Changed oil and filter, fuel filter,
DIY Tymar intake with the huge (barely fits under the hood Donaldson filter)
Sticktion eliminator and Diesel extreem
Drove a half tank keeping it under 2K RPM, 10 MPG.
I run empty, no trailer, no load. Driving is always around town, stop and go stuff.
3.73 gears with 33x11.5 tires, extended cab
Any idea why it remains 10 MPG no matter what? Could I have a clogged EBP sensor or failing injector?
Up pipes "look" fine, no soot that I can see.
I have never seen boost go above 15# seems to kick in around 1500 RPM maybe, not sure as I have not paid attention to when it kicks in.
No smoke, no engine lights.
Will check for pin holes and tears tonight.
3.73 confirmed
Primary Features
Build Date: 18.07.2002
Vehicle Line: F250/350/450/550 Super Duty
Body Style: Super Single Cab
Version: 250 Series
Engine: 7.3L Diesel V8 Turbo
Transmission: 4 SP Auto 4R100 (Diesel APPLI)
Drive: LHD 4WD (PTD)
Axle Ratio: 3.73
Emission: With 49 State Emission Requirements
Air Conditioning: Manual Air Conditioning
Territory: (+)"USA"
Paint: Dark Shadow Gray
driving around town stop n go is going to get that mileage with a one ton diesel...
I got 14mpg my worst tank in my 99 but I take a lot of dirt roads with no stop signs. I don't think the truck is bad, its the driving in town full of stop lights. Do you have a monitor just to be sure though?
Technically it's not stop and go, its short 5 mile trips at no more than 45 MPH from home to work. Occasionally there is city driving and very little highway so far.
These trucks have a TON of sensors feeding information into the ECM. if one of those is failing or a mechanical part has failed it would affect mileage so a monitor like the torq pro app on an android based tablet or phone and then a blue tooth to obdII adapter would let you read the readings from your ICP sensor, IPR sensor, Boost PSI, HPOP pressure etc. It can save money versus the throwing parts at it because these trucks are expensive.
I am willing to bet there is a boost leak (not always easy to find without a monitor) or its the stop n go. your truck weighs over 6,000 lb and even with a diesel stop n go really kills the mpg.
Have you checked your brakes to see if any dragging? the caliper guide pin guide bolts have been know to stick and that could be a factor with the reduced mileage.
I think I figured it out and maybe someone can correct me of I am wrong.
Original tire size is 265/75/16
New tire size is 285/70/17
According to tiresize.com @ 45 MPH I am actually traveling 46.5 MPH. This is a difference of 1.5 miles.
So I recalculate last mileage of 127.9 and times by 1.5 gives me 191.85 miles driven
I then divide that by gallons used, 12.03 and I get 15.94 MPG
Yes, yesterday I used a speedometer/GPS app and it is very very close.
I am in the middle of restoring a camper before Sukkot (10/16) and have no time to work on the truck till after then. At that time I have a list of things to check.
Yes, please elaborate. I have read many posts about this but I am unsure if by wiring open they mean disconnect harness and put in a loop wire to maintain signal back to computer or use bailing wire and tie it so the valve holds open.
Is not the default position open? If so can you not just unplug the harness which would allow it to remain open without wiring it to secure position?
So my old roommate has a 4dr long bed 97 and he does all town, short trips he gets 10mpg at best too. It might just be the stop n go man.
He said it's been that way for about a year now. He's got 35s, leveling kit, and. Ts 6 pos chip with 6637 intake. 253k miles but he's rebuilt front end, trans, new bearings and seals in rear, rebuilt turbo etc
So here is something interesting.
The last 3 fill ups were hand calculated to around 8 MPG.
This last time, I did the same around town driving to work and back and then pulled a 5K pound trailer about 20 miles on back country roads. Filled up and calculated....
16.5 MPG! WTF?
The only thing I have done is disconnect the waste gate hose.
The only thing I can think of is maybe the oil in the HPOP has finally recirculated and is now the clean stuff I put in a few hundred miles ago, if that is even possible to cause such a thing.
Not to hijack the thread but I've put a tank and a half through mine since I picked it up and I'm getting right at 13 mpg, it's my DD and my drive to work is about 5 miles of sprinting between stop lights then about a 3 mile run at 60 mph.
The worst I've ever got was 12.7 mpg in December all city long warmups, 2 year average is 14.7 and best was 17.7, most of the time I'm keeping up with traffic, rolling coal once in a while >
What surprised me was how little difference there is between all highway and city mileage compered to a gasser.
fwiw, i get 13 - 14 tops. really, no matter way. similar to you.
i've just done up pipes, rebuilt the turbo, riffraff wheel, and am
putting a 4" exhaust on. will have the ts 6 on it as well once i get
it back together. kind of anxious to see if those changes gives
me a bump or two in mileage.
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