I have a 2001 Dually HO Cummins 6 speed,3:54 ratio.
I cannot get better than 17 MPG if I was getting towed.
I hear reports of 25-29 MPG with these diesels...Is there something wrong with mine?
K&N airfilter,amsoil in motor.everything is just about stock....

I am ready to sell this thing!
Is my injector pump bad maybe?
or is 17 MPG driving like a grandma expected mileage???
Thanks.
DD

 

More information would be helpful here. For example, are you 4wd or 2wd? How long have you owned it? Do you use winter blend fuel in KY or not? (Makes some differance in my experance). 17 MPG is that highway only? Do you have a fuel pressure gauge and do you monitor the fuel pressure to tell if a lift pump is begning to fail (needed on these 24V trucks.)

Take a minuite and breath easy. Selling a truck due to 2-4 mpg less than you expect will take you a long time to make up in lost money on a transaction. In truth, hand calculated, my mileage with my truck in the signature, which is one of the most fuel effecient, lightest-weight rigs with the Cummins, is around 17-20 in town (winter to summer) and 21-24 mpg highway (winter to summer.) I question the accuracy of anything above 25mpg with a 6800+ lb truck that is rather poor aerodynamically. And all things considered, low 20's is exceptionally good for something that heavy. Got any friends running a GAS 5.9 V-8 truck? Ask them if they want to trade...

 

I'm on my 4th dually never got better then 18 out of them they were all 4x4 my wifes is a 4x2 and it gets about 19 on the highway. a lot of these numbers are from single wheels they always get better mileage

 

I've never seen any better than 15 mpg out of my rig, the mods that I have made have only increased the economy.
Them two extra wheels really get ya in the fuel economy department .

 

Those "Reports" you got are BS, my 2500 4WD gets a little over 20 un-loaded on the highway, and that's with a double-overdrive. About 15 towing 10K. I figure it gets about double what the comparable gas big-block version. Case in point, a guy we race with tows with a Dodge Dually V-10, and he stops twice as much as I do!!

Tom

 

Bad "reports" I would say. I have an '01 SRW, 4x4 no mods driven reasonably I get about 16.8-18.2 NEVER much more, with a load more like 14 to 15. Now I don't know much about what the DRW does to you, but I would imagine you would loose .5 MPG or so.
My brother in law has a '96 SRW 4X4 short box, he is doing good if he see's anything over 11 (seriously). Load it up and forget that, more like 8-9 MPG!!
Be happy with around 17, you might get 19-20 if you keep it around 60MPH with no head wind over a couple of hundred miles of flat ground.

 

My truck is a 2 wheel drive,I had the fuel transfer pump replaced under warranty BEFORE any signs of trouble.
Truck has 120,000 miles.
I have owned the truck since it had 50,000 miles (3 years)

 

I have achieved 19 and change on a road trip on more or less flat road, unloaded, tires at 75 psi, and keeping the speed at ~60-65 mph.

Booooooooring.

Usually ~17-18 driving normally on the road, and ~16 in town when avoiding the "Stop Light" drag races.

Keeping the Boost readings below 10 psi helps.

 

When I bought my truck it showed 15.5 avg mileage and was pretty close, a friend was getting a verified 20+ so I started bombing, the superchips was my firs mod it brought me up to 18ish, then I installed the Van Aaken and injectors which brought me up to 21+. the odd thing is with just the tuner I got best mileage at the lowest rpm, after the VA 1800-2000 was my peak mileage area, my truck last went on a 350 mile unloaded rt and did 23.6 mpg verified on paper. I have since installed the drag comp so it is all out the window now Oddly enough I hear many people say their over head console is haywire on the mileage, after adjusting for my tiresize with the tuner, mine was never off by more then .2 mpg! that was with the tuner and the tuner and VA, I think the drag comp has screwed it up. I assume the added timing is what does the mileage number, I have also been told that fue lpressure affects the timing of the vp, that said my fp never dropped below 20 at cruise...did that help? who knows, but it is WAY cheaper to drive now then when I bought it about 150 miles to the tank cheaper!

 

want to trade my chevy 1ton drw gets 4 mpg towing my TT, and you complain?

 

Trade??
I will pass thankyou.
4 MPG!?!?
How can you afford to keep something like that?
The $$ you save on fuel would make the payments on a Dodge Diesel.
What is a "TT"?

 

TT = Most likely a Travel Trailer (Bumper Pull)

 

I am with the rest of you. I get about 16 unloaded and 13 with my fifth wheel on. I just started the mods and am hoping for a little improvement. at first I was disapointed but now i am used to it.

 

When someone says they're getting 29 mpg they are flat lying to you. The best I've gotten in my truck is a touch over 20 and being very gentle with it... no racing from dead stops and keeping the rpm under 2000.

 

The best I've ever seen on paper out of my truck is 23.1 MPG.

I've been keeping a fuel record for the last 3 years of ownership and the software I run gives me a total average MPG number back which is in my SIG below.

Don't race from a stop to speed limit.

Don't let the boost climb high above 10 PSI. Try to keep you boost down low...

Don't try and run over hills / long grades at speed limt (reduce your speed -10)

Try to unload anything not needed in you truck. (Reduce your weight if possible)

Leave early and let you truck warm up. Also try to keep your engine warm. (For colder climates) I've noticed a huge decrease in MPG if you have a day of start and shutdown for short trips (less than 5 miles). The engine never seems to get out of the cold cycle and consumes large quantities of fuel.

Enjoy the day... No need to hurry!

Yeah I know it a Cummin's it need to be taken out for a good race once in awhile!