Help! 7.3 milage. What works

[PJ-Hunter]

Believe IT!!!!!!!!!!

I have a 2003 F250 shortbox with the 7.3litre. I installed a 4" exhaust, installed a cold air intake, cut a much larger hole at the intake located on the Driver's side behind the grill.

I have a 4" ProComp lift and I run 35s. I also have a big Ranch Hand bumper, mainly to keep deer and elk from ruining my intercooler.

I have always run a chip. The first on was the Bully Dog 4 bank chip. I now am running Bully Dog "Triple Dog" tuner and it rocks!
http://www.bullydog.com/product.php?ID=2&ModelEngineID=259&Year=2003&MakeModel=FORD F-SERIES 250-550 It has a ton of features and it also calculates mileage and grades you on wasteful energy. When I'm taking it easy (65-70) and just driving empty I can get up to 24mpg (depending on where I am driving. With an enclosed trailer (loaded) I drop down to 13-16mpg. And I know that the tuner isn't calculating wrong. I have manually figured it out too.

I want to delete the muffler but it sounds weird. Kinda fluttery. But I have heard that you can get a noticeable increase in power, lower EGTs and better mileage by taking it off. My brother did his on this Dodge and it ran better, sounded mean too!

I also figured out that I get better performance and mileage if I tow in the performance setting instead of the Tow setting and my EGTs very rarely get to 1100.

 

[scratley]

24? Wow! Never heard that before. Did you notice how much of a gain after each mod? Or did you do them all at once?

 

[Snodawg]

2002 F250 Extended Cab 4x4 Stock exhaust w/ muffler delete, AFE stage 1, leveling kit with 315's, no chip 140,000miles.
17 MPG Hiway at 74 MPH
15 MPG City

BTW Muffler delete is not too loud. I had the same concerns, but love the way it sounds now except when your outside of the truck and it goes into warmup mode......sounds horrid then.

Highly doubt that I will ever sell this truck (even if I buy a new one). It's just been too good and it's a 7.3.

 

[Blk88GT]

No way you're getting 24 hand calculated MPG. Maybe on the gauge, but not calculated.

 

[psd1]

Best way to improve your mileage is to slow down.

 

[suva]

Best way to improve your mileage is to slow down.

Yep....
In the work truck (06 cummins) I get 19-22mpgs, when the old man drives its 15-16.
In my old Ford (95 5 speed powerstroke) I can get just under 20 if I keep it at 55 or so, at 65 its down to about 15.

 

[Wheel House Motorsports]

driving a lot of country roads in the summer cruising at like 55-60 i get consitantly 17-18. start cruising the highway at like 75-80 she drops down 2-3mpgs.. it doesnt like getting into boost.

as for getting 24.. how is the downhil tailwind??

as far as muff delete. they sound nice. i had my stock setup with no muff and its really not that loud at all.. i moved it so its stock to where the muffler was then it kicks out 4" tip in front of the rear tire. sounds nice. not to loud but has a nice roar if you whack the thing to the floor. but as someone said.. when it goes into warmup mode, or as we call it, "space shuttle mode" its retarted loud. mine is actually painful if you stand right by it.

 

[merlin2569]

2001 F250 3" Lift and 33's. AFE Intake, Bully Dog Chip, and MBRP 4" Turbo Back Exhaust. Get 9-11 pulling my 30' enclosed with 6 sleds in it going 75-80. Goes up to about 15 it seems like no matter what speed I drive without the trailer behind it. With that said i wouldn't give up my 7.3 for anything. Bought a '08 6.4 3 years ago had it for 8 weeks and it was in the shop for 6 of those weeks. Luckily i hadn't sold my 7.3 yet and probably never will. The 7.3's are never gonna make the power or get the mileage that a 5.9 cummins will but they are the most reliable diesel engine out there. Just my .02 on them.

 

[4GR8X]

Verify your 35" tire size has been entered into your trucks programing software. If it has not been done you should see your shifting points change for the better. This should improve MPG and performance some. Not a super expensive task. I've had mine updated at my local Ford dealer.

Is your gearing 3.73?

 

[rdr99]

Measure the circumfrence(sp) of your tire then figure out the revolutions per mile, this will help the programming do the best shifting.

 

[PJ-Hunter]

24? Wow! Never heard that before. Did you notice how much of a gain after each mod? Or did you do them all at once?

All at once

No way you're getting 24 hand calculated MPG. Maybe on the gauge, but not calculated.

Hey. maybe it's special. All I know is that the programmer calculates MPG and fuel usage by gallon and it always matches up within 1/2 gallon each time. I won't argue with that. I do know I'll only drive it on weekends now and not very far. Pretty sad that diesel is just a few cents cheaper than jet fuel. If it goes up, I'll start running jet fuel, it can be done with no mods

 

[scratley]

Verify your 35" tire size has been entered into your trucks programing software. If it has not been done you should see your shifting points change for the better. This should improve MPG and performance some. Not a super expensive task. I've had mine updated at my local Ford dealer.

Is your gearing 3.73?

Yes it is. I am guessing the computer has not been done. It shows 77 mph when i am going 71.

 

[dmkhnr]

Yes it is. I am guessing the computer has not been done. It shows 77 mph when i am going 71.

You gotta get that fixed. Your shift pattern is way off, the truck probably feels like a dog. If you call dp tuners and get them to burn you a chip, they will correct the tire size and shifting points.
You can also send your ecm into dp tuners and they can reflash it with their hp tune and correct your speedo for under $100. (great deal if you don't need to drive your truck for a week.)


I get 100 mpg when driving down the grade (hwy 50 from lake tahoe) so I've got your 24 mpg beat by a long shot. Honestly, I've heard of 2wd manual transmission single cab 7.3 breaking 20mpg. At 24 mpg I could almost drive 1000 miles on a tank of fuel.

 

[vdog0531]

i did the 6637 filter with a 4" exhaust on my 03 with a 7.3 and had innovative diesel do some custom tunes on a sct x3.... love it. driving on the aggressive street setting like a 16 yr old in the first tank of fuel netted me a hand calculated gain of 1.5 mph. Once you get used to the extra power and drive her normal, you will see lots of mpg. more air intake, more exhaust flow and some custom tunes.... huge difference

Vernon

 

[scratley]

Thanks guy's i appreciate all the info. I am going to do one thing at a time. Like i saisd i don't drive it much. 200 miles in the past 2 months. And now it will prolly sit till fall. Would like to sell the nitto 35's though. They are the new trail terrain tire. would take 200 a piece for em. paid 320 fronts are like new rears are maybe 75 percent. 18 inch wheels

 

[Rixster]

Park it, then it doesnt burn any fuel !

 

[Top Notch]

Has anybody tried a F.A.S.S. fuel pump on a 7.3? If so what kind of results did you get? Or any other after market pump?

 

[scratley]

Park it, then it doesnt burn any fuel !

Thanks Bro! Yeah that seems to be working well. 60 bucks to fill the damn car. Think the truck can sit till winter

 

[cowboymann02]

I also have a 2000 f250 shortbox turck that has been modified. heres a run down for you. gets me 16 MPG in town all day.

AEI intake (larger 5 7/8" intake filter)

4" cat-back exhaust to rear of truck

bully dog programmer (that way you have 3 setting to choice from) or sign a waiver for the CRAZY LARRY set if you want to break parts) HEHEHEHEHE

Banks big head waste gate actuator

285 kelly brand attitude tires

Plus here is a bonus that most guys don't know about with the older 7.3 & 6.0 motors. there is a small fuel line sping and fuel filter that is usually mounted into the casing of the fuel filter housing, on my 7.3 it is on the top right side of the fuel filter housing, this spring gets weak over time and starts to rob the truck of fuel milage. loss pressure in fuel filter area. i just got mine last week for a cost of about $56.00 at ford.

the filter spring kit should contain 3 o-rings, a spring, and small odd shaper retaining nut/cap and a small inline filter (1/4" round at most x 1" long)

hope this help you out and good luck.

 

[Snodawg]

Do you have the part # for this "kit"?