7.3 fuel mileage question

[skyfish]

Tire size

Hello, I have been looking around here and noticed that everyone is talking about recalabrating the computer to fit tire size, I know that this is an old thread but I wanted to give some info:

I have a 2000 F-350 Crew Cab 7.3 4x4 I got new in 2000, I dont remember what the stalk tire size was but they were smaller, after they worn out I put some BF goodrich 285/70/R16 on it and my speedo is 100% correct (I have checked it with a GPS unit at speeds of 90+ over long distance 200+ miles using my cruse control!)

The only explnation that I have for this is that Ford and Other's under clock the speedo because tire's are not the same size from one manufactior to the next, there could be some legal resson aswell.

 

[bartman]

I believe 285/70's and 265/75's (stock) are about the same overall height thereby not changing the way your speedo reads.

 

[skyfish]

I believe 285/70's and 265/75's (stock) are about the same overall height thereby not changing the way your speedo reads.

I do know that I went with a taller tire when I went to the 285's (I wanted the extra clearance for 4x4 roads hear in Colorado), and the new 285 spair barly fits in the hole I had to "force it in" and the factory tire had some play. The tire's that came with the truck only lasted 20k man they where junk!

 

[bartman]

I have seen some junk factory rubber on trucks, but 20k is ridiculous.

 

[skyfish]

I have seen some junk factory rubber on trucks, but 20k is ridiculous.

Thats what I thought!!!
and they was BALD at 20k!!!!
I tow alot of weight but I would expect to get more than 20k!
I get about 45k on my BF Goodrich and thats to 1/8" tread

 

[s d mills]

Phil, previous owner of my truck, said he got 33K out of the factory Generals and switched to UniRoyal Laredo AWPs that were on it....still serviceable but worn to replacement bars when I bought it with 78K on the clock. I figured 45K was reasonable relative to the price ($115 ea mounted/balanced, tax, etc which dealer paid). I've now got 19K on them and the rears are still like new. 60% of the mileage is from pulling a 7K loaded car hauler.

He had Dunlop Radial Rover ribs on the front....they were wearing funny (outside edges). I had the alignment/ball joints/tie rod ends checked when I bought the truck....all okay. I wore the fronts completely out over 19K miles, had alignment etc. checked again....I'm shocked! Ball joints are now shot.

I just put UniRoyal 235/85/R16HDs ($262 out the door) on the front and truck's mostly sitting in the driveway until I have time to throw ball joints in it.

I have high hopes!

Oh....fuel mileage has remained 16-17 mpg unloaded rural, city and highway; 12 pulling the car hauler, with summer fuel. I averaged 15/12 over last winter. Whatever gains I might make in mileage on the interstate are probably lost from cruising at 75 mph.

 

[chickiepickie]

Remove those sh%thole tires and drop some 10 ply low rolling friction tires on that truck and you could get 4 to 6 more MPG believe it or not.

 

[ljmoya]

During the rally I spoke with a few people about fuel consumption. From the info I gleaned, I have determined that I am burning a ton more diesel than others. When I got it, I was getting right at 12MPG. I have completed the mods below as well as an Edge Evo programmer which i run in the middle tune, and I now get 12MPG. So, the programming yielded me zero. I have not changed my driving habits, and all my numbers are hand calculated and I fill to the brim with each fill. I know that it's 4x4 and CC and LWB, but others with similar or even bigger setups are getting closer to 16MPG. I want to know what's with my mileage and how I can fix it. Any ideas would be welcome.

Thanks
Bart

I am in tha same boat that you are in when i first got my 2002 7.3 truck I was getting around 18 MPG on the highway and 14 to 16 in town Now I am down to 12 MPGSin town and 14 on the highway. I will change out the gas filter I havent done that for a for the last 12,000 miles. So I will try that. I had a new transmission installed I burned the old one and I thought maybe that may have some thing to do with it, I dont think so. I have a bully dog chip on mine and when I bought it I had it programed for a standard transmission and now I am sending it back and having programed for a auto, which is what I have, but I have had that chip on since day one and I dont think that could be it: but I might as well have it programed correctly.I havent thought about changing the fuel filter. I also have 4 inch exhaust, a K&N filter, gauges. I also installed a cam postion sensor before the old goes out and that didnt help with the milage. A friend of mine also told me to clean tha map sensor with a cleaner that you can buy at the local auto shop I did that but I havent drove it long enough to tell the difference.I really is upseting that the MPG decrease, you would think as the engine breaks in the MPGS would be better. I will let you know if the chip helps and the filter.

 

[bartman]

Cool, thanks. Also, let me know about the map sensor results.

 

[dzl_x_4x4]

Have ya' tried washing the motor? I think that the "FOO-FOO" package costs you 3-4MPG's.

I betcha' haven't changed your driving habits, do you pass cars now you couldn't have passed before? There is your answer!

If you got those numbers at the Rallye those are "Beer Adjusted" MPG's. It is a different numbering system all together. I am sure my mileage goes up after a few cold "1's".

During the rally I spoke with a few people about fuel consumption. From the info I gleaned, I have determined that I am burning a ton more diesel than others. When I got it, I was getting right at 12MPG. I have completed the mods below as well as an Edge Evo programmer which i run in the middle tune, and I now get 12MPG. So, the programming yielded me zero. I have not changed my driving habits, and all my numbers are hand calculated and I fill to the brim with each fill. I know that it's 4x4 and CC and LWB, but others with similar or even bigger setups are getting closer to 16MPG. I want to know what's with my mileage and how I can fix it. Any ideas would be welcome.

Thanks
Bart