I'd like to know if my fuel economy is up to par or if I'm missing something.
The truck is a 92 D250 club cab 2WD automatic. 3.54 locker out back spinning 275/65-16 tires.
The fuel pressure has been given one full turn, the smoke screw was tweaked and the pin was rotated. My muffler magically disappeared and that's about it. No other mods.
The truck is sitting at 241,000 miles.
I get right at 17 mpg in the city and 17 to 18 mpg highway unloaded and cruising between 65 and 70 mph.
At higher altitudes the mileage improves a bit.
Filters are clean and tire pressures are fine.

Should I be getting better mileage than this? On road trips, I usually let the speed vary with hills (love that gravity mileage boost) and drive by the boost gauge. I keep the load on the engine about the same whenever possible, even if it means slowing down a bit.
Towing light loads gets about the same. Hauling 6000 lbs or so (hot rod on open trailer) I get about 15 mpg.
I'm about to drive from Dallas to Syracuse to pick up a 2000 lb mill. It's a 3000 mile trip and I'd like to get better mileage if possible.

Whaddya think?

 

Did you correct for the different sized tires? I get 16-18mpg with my 92' W250 empty.

 

Maybe I got the tire size wrong. I'll have to look again when it's not raining.
They are the same height as the stock 235/85-16. Less than 1/4" difference.

 

Got 23mpg empty when the speedo was working in my '92.

 

I'm getting 22mpg empty running with a right foot that only knows one position
truck is bone, I mean BONE stock with auto.

Now if only I could get some more power

 

I'm getting around 23 empty in my 91. Pretty consistent, even with some loads here and there. I haven't turned anything up though, which I'm sure affects mileage.

 

I am getting around 22-23 empty and about 18 pulling an 8500 lb load. Only mod is having opened up the stock AF housing.

 

If you want improved mileage outside of what you have done, I would get the timing set. If it hasn't been done yet, get that done and have them advance it a degree or so from the stock 10° at idle. Advancing the timing will help.

Also some fuel conditioner would help to clean the system a bit. Better injector spray pattern gets you better power and mileage. If you burn it better, you use less.

Performance modifications will not affect mileage greatly unless you are using full throttle all the time. Whether you have 180 HP or 600 HP, you use the same power to cruise down the road. Diesel only use as much fuel as required, its not mixture based like gasoline engines.


Hope that helps a bit.

J-eh

 

geesh, id be jumpin for joy with that MPG. jiMMy

 

I wish i got that mpg. but my 14 size shoe doesnt seem to stay off the go pedel. lol

 

My size 15 may have something to do with it but I'm not amputating!

 

Even with the speedo no longer working, and the mods on the truck...it seems I get about the same mileage as before. I just keep my foot out of it and try to stay out of heavy boost on road trips.

 

you're getting good mileage as it is. Anything better than 20 is exaggeration, basically. I have a 93 D250 clubcab AT and I've managed 16 to 20 consistantly city and highway combined. I had a best with the wind at my back of 25 mph on a 400 mile trip. If you want better than that buy a halfton with a 4 or 6 banger in it. Otherwise, you're asking for a miracle.

 

My last fill up, which is to the rim where i can see the fuel was 28.2 gallons 614 miles. That was one tank of fuel. I fill up and then go 100miles after the light comes on to refill. The big increaser seemed to come with the 4" exhaust. I just changed the air cleaner from stock to the 14" cone that is the same used in the scotty 2. I'll let ya know if it makes a difference when i get back from alabama. I plan to drive the 500 miles and 3days of misc running around on the first tank and fill up for the results before the trip home.
-Jim-

 

What Lil Dog and cdodgeguy said. I never got any better mileage than you're getting when my truck was stock, now I get about 15 mpg in town due to my injectors. You're doing OK, but advancing the pump timing may help a little.