Fuel Economy
 

I'm getting a combined MPG of 14.5 or so , I tow often but LIGHT I tow about 2k about 3 days a week and run empty the other 4, I have heard of a LOT better mileage from these trucks and am wondering what I can do to get mine up to par. I just got the truck a couple of weeks ago. I am going to change ALL fluids this weekend (oil, trans, rear end) as well as add a BHAF (baldwin) I have already checked tire pressure as someone once suggested but no other ideas. Help if you can..

keep the boost down and your milage will go up. the more you stopm on it and the longer you hold it down the worse your milage. bhaf and a straight pipe will help to:cool: good luck

I added a VA box which made my mileage go up about 2 mpg. The down side was I burnt my clutch. I plan on adding injectors next. Be sure to put in a fuel pressure guage. These trucks are bad at having Lift pump problems and injector pumps going out.

Is yours and auto or a manual? I have a manual '96 and I average 18-20 around town, nearly 24 out on the highway. Also I do not have any injection pump "upgrades." I'm not in a hurry when I drive either, if so I would drive a German vechile...

auto, piped, intake... HEAVY right foot

10.5ish all city no towing... and diesel just hit 1.99 here... makes me happy

I'm going to have to relax my foot if I ever want to replace the broken shocks on the not so old beast

I just turned over a full tank that included around 400 miles hwy avg@ 65mph.
3 hours worth of steady 5-15mph off-roading in 4x4. Few 5 mile trips between 2-50mph. I have a slightly heavy foot on the hwy, especially in the mountians, were around 200 miles of the trip took place.
MPG came out to 19.6 mpg.

You may want to do some basic checks in the airflow and exhaust dept. BHAF and straight pipe help alot in fuel economy.

I have found that I get almost the same mileage towing the empty trailer as loaded. There are a lot of factors that hit mileage. Four wheel drive hits it, especially on the later models with no disconnect. Posi rear gears hit it some especially on curvy roads or residential. My right foot costs me a lot, drive it the same with the trailer as without. I have a habit of racing ricers with the trailer on. And you have to show the F350's and Duramax's that you have a Cummins.

Too low an rpm hurts mine quite a bit. It likes 18 to 2200 for mileage. The best mileage that I can get out of it is about 53 mph in direct. Too much oil will hurt mileage. The 140 rear axle lube will cut it a little, expecially in the cold weather or short runs. Articles I have read say that running with the tailgate down will hurt it some also.

Oh well just some thoughts.

Keep your foot out of the "GO" pedal! Add a 4'in. exhaust and get yourself a chip.
My mileage jumped up 3-4 miles after I added a chip. When I run out of state (California) My mileage goes up even more. Towing 6,000 pounds runnin 70-75 I average about 15mpg, Empty 23+.

What type of rear end do you have? 4:10 or 3:54?

I too am blessed with poor fuel economy! Its about as nice as long walk off short cliff . I have changed all fluids, most filters, put a K&N, checked tire pressure, straight piped it, chipped it and turnbuckled the turbo. Darn near left the carrot dangling in front of its nose!
I still get 9.5 to 10 whether i am towing 9,000lbs around town or empty down the highway with featherfoot driving. I have seen a few other people with really bad mileage, but they all seem to have come to the conclusion that this was okay. If anyone can come up with a magical cure to aid some sickly Cummins, I'm sure we would all apreciate it. Or any other suggestions would be great too.
:confused: :confused: :confused: :confused:

I too am only getting an average of 14-15 mpg. The best I ever got was 18. Driving flat Montana highway at about 60 mph. I would hate to see what I would get if I were to tow anything. I drive what I would say normal. No heavy foot or quick starts from a stop as I have a 6 speed. If I were to drive any easier I may as well get rid of it and go back to a 4 cylinder import truck. (My 96 Mazda got about 31 mpg) Actually with the price of fuel it may not be such a bad idea. Went from 2.09 to 2.29 over night here.

:(

If your 12 valve has over 80k miles I would suspect the catalytic converter is clogged up. Remove it and use a straight piece of pipe.

OK, This weekedend while changing fluids and filters I am going to add an BHAF and may straight pipe the CAT.

Haulin dixie- I think you may have somthing on the RPM's I do drive around back roads a LOT running 40-45 MPH (I am a landscaper) so that may be part of my problem, I may try manual shifting the auto and see if I do better with higher revs.

Farmerdave- I have a 3.54 rear axle

Maybe I am driving her TOO lightly my dad has been a diesel mechanic for years and told me to "run the h*** out of it" and it will do best.. I dont know what to try next but SOMETHING needs to work, I was pulling the same load with, get this, an s-10 pickup with a 4.3 v6 and auto before and got 16+ MPG.. SAME LOAD SAME ROUTE...

Maybe I can remedy it this weekend. We'll see..

Mine has been junk, also. I had hit 19-20 last year with a mix of towing, then it just disappeared. I've lately been around 16 or so, no long trips, but we'll see what we can do this Sunday if I make it out to the drags in Wisconsin. Want to see some real highway mpgs. This is with timing at 16.5, Goerend Tranny, 3.54 gears, I'll admit the last couple of tanks I have been pretty hard on the skinny pedal:rolleyes: Getting stacks will do that to ya:D I am trying to run a tank through as a "responsible" driver:cool:

Adjust the valves and set up the timing.Kill the kitty and run straight thru exhaust or at least a 4" w/good muffler. What are your gears? I am running straight exhaust,K&N,timing at 16.5 and fuel plate pushed forward and can get 20 mpg if I am easy on hiway,and 17 comb.driving (It does smoke when I have My foot in it).I think the timing really made a difference in the mileage though,besides it ran like a different truck.I have 4.10 gears with 35 inch tires.<><