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Dave

fuel mileage questions

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Im getting 12 gpm empty and about 10 with an unloaded gooseneck trailer. Is that all I can expect or is somthing wrong with my truck? its got 36000 miles on it

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let it breath if you havent all ready also what gear ratio do you have i am betting its the 4:10 have you seen an incress at all since you have had it also is this over head milage or hand calcuitaded

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Wow,2500 with a low revving Cummins! I know that most trucks (Duramax, Cummins, Powerstroke) fall on their face for mileage at anything beyond 2000.

I know I can get right at 20MPG running at 70 mph, Drop that to 65 and I will see 22. Raise my speed to 75 and I will see slightly better than 16. So I could almost see 12 to 14 for running 80 in these trucks.

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I hope you mean mpg (miles per gallon) and not really 12 gpm (gallons per minute... or I suppose gallons per mile in this case)

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hey Im just a dumb well digger :smart: I dont know what all those letters mean :roll: I got my letters mixed up

That's KO dave I get my Mords Wixed up a lot too.

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Which truck are you talking about, I see 3 in your sig.

If it's the 06, that sounds about right. My boss has a 06 MegaCab and he gets around 14mpg unloaded and normal driving.

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like i tol ya 2day dave,,,,id get 20 on my 2 03's,,,,,,[srw and drw's] but 18 was common. i didnt tell ya that i took my 03 srw on a rd trip at 80mph and only got 14. of crse the wide fltbed with wide wind blocking hdche rack didnt help.

since fuel went up,,,,i slow down and get good mileage. taint NO way an 04.5 and newer will mtch milge of the earlier trucks tho

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I guess I was thinking it would get as good of milage as my 01 which was 12 MPG way overloaded to 17 MPG empty. hopefully the fewer brake jobs will make up the difference overall

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Guest ShanesLB7

I get 18 mpg steadily and drive like a bat out of hell!Loaded pulling 16k I get anywhere from 12 to 16!! I've got 40k on my mega cab

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I am with Shane, I took a trip to California and traveling 80 + most of the trip, I got 18.7 MPG hand calculated and i have 37" tires and the damn thing is nearly 9 feet tall. Back her down a bit and you will get better mileage. Sounds like you have 4:10's and a manual tranny? install taller tires and let her roll out a bit better

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Im not sure of the gearing but I assume your probably right. It already has 285s on it my problem is I pull gooseneck trailers with it. How tall can I go before it starts getting dangerous? with the tires I have on it already feels a little greasy with a load

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Guest ShanesLB7
Im not sure of the gearing but I assume your probably right. It already has 285s on it my problem is I pull gooseneck trailers with it. How tall can I go before it starts getting dangerous? with the tires I have on it already feels a little greasy with a load

I have a leveling kit and 35's and pull a 30' gooseneck with lift all's and heavy equipment just make dang sure you have heavy duty tires!!:thumbup:

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the gears on on the tag in your glove box door. i just got an early 04 6-speed and come to find out it has 4.10 ratio. Not sure if i want to run 37's on this truck or swap in 3.73 as i have a set sitting on the garage floor.

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4.10s and 37 would be good, if you tow a lot I would almost swap in 4.56.

35s and 4.10s is perfect in my truck. I had 3.55s and it was terrible for towing.

Now 70mph is right at 2000rpm. Perfect. I get about 14mpg towing my Jeep at 70-75mph.. about 16000lbs combined weight.

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Well if I go any faster parts start flying off the Jeep :lol:

My setup works pretty good. Went down to Moab, Ut this year and only on the biggest passes I had to keep an eye on the EGTs and just barely back off to keep it under 1250*... I was still able to maintain the speed limit. I think I dropped it out of overdrive once just to spin the engine up a bit more to cool the EGT.

It's awesome passing gassers that are doing maybe 40mph up a 65mph pass and they look over like :shock: :shock: :shock:

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Haulin our 25ft bumper pull camp trailer to cascade we get about 13-14. Way back is a little worse, because horseshoe bend is a pretty big hill pull up.

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I don't know if the original poster is still here.... I have about the same problem as he does.

I say problem because this isn't my first Cummins. The others beat this truck pretty badly for mileage so I know this one can do better. He probably has 3.73 gears as my last truck was set up the same way. I recgonize his numbers as far as speed and rpm. The new trucks don't have the sticker behind the glove box (Or was it in the box?). You can check your gears here: http://www.klenger.net/dodge/general-reference/gear-speed-calculator.xls

You can enter different values for tires and such and it will re-calculate for you.

Ok, my question:

My truck can be driven slow (about 65 mph) and it will get about 14 or sometimes 15 mpg. Hand calculated and I even made sure the speedo and odometers were correct. I have owned this truck since Nov '06. The mileage hasn't changed since day one. My last truck was just like the op's. My first Cummins also got better as time went on. In fact, after a big trip with a good load, my mileage really improved! Not this truck, and I have had it on several break the bank trips with the trailer (low as 8 mpg!).

Anyhow, I have noticed that #2 injector is extremely loud. The rest are quiet. I don't know if that is a problem or not; but, I have to wonder. The rest are pretty quiet. I have taken it in three times complaining about low power and poor economy. They say it is fine since the computer has no codes in it. I tell them that I didn't know that the computer listened to them.....

What I want to do is to find someone who can work on her that is 'authorized'. I figure that Chrysler should pay for the injector and labor. Even if it can't be worked out that way, I want to find someone very competent to work on it. I might even go for all new injectors if someone can recommend ones that will improve my mileage a good amount. I really don't care about power, never have. I want to tune this truck for maximum mileage.

Any and all ideas you all can give would be really appreciated!

Thanks,

Dan

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I put a smarty on my truck and it improved a little bit I can get 450 out of a tank now before I was only getting 400 or so. that was filling up when the needle got to the red so a little under a mile and a half improvement but the power is better so I can live with it

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