dbeer

I have an 2002, 2500, 4x4, completely stock other than a K&N air filter. I’ve been getting only 14 mpg. Before I was getting 18 to 20mpg. I ‘ve been around 5 Cummins of various years getting 20 mpg or better. I have replaced the lift pump. No help. Fuel filter. No help. Regular oil changes. No help. Changes in fuel. No help. Fuel additives. No help.



One mechanic says a problem with injector timing, another says that’s not possible due to the computer. Another says, valve adjustment. I feel like a doctor is saying “here, take this pill and see if it helps. And by the way that will be $200.00”

I ‘m am not interested in chips, exhaust, air intake or any other modifications until I can get my mileage back to at least 18 – 20 mpg again, where I think it should be (at least) It should be getting at least that, with just stock equipment. Any ideas? Please help.

KATOOM

How long has it been since your fuel mileage has dropped? How many miles on the truck? Whats your fuel pressure? Has your VP been replaced? Whats your engine temp been lately? Remember that diesels like heat and your fuel mileage will drop a little in the cold winter weather.

SIXSLUG

Winter fuel?

Change in driving routine?

Auto trans? Is it slipping?

rickf

Did THAT truck get 18 - 20 or are you comparing it to others that do? What gears are in the rear? What is your driving style? A lot of questions to be answered before you can get an honest answer. Mine is all stock with 4:10 gears and I am getting consistent 15 MPG.



Rick

anotheraznguy

wow.. i dont know how you guys are getting so low mpg..
im getting 21-23 mpg city/hwy mix

have you checked your boost hoses?

KATOOM

Are you using the overhead display or are you hand calculating? And even at that, are you calculating the right way? I say that because there is loads of wild fuel mileage claims and then there's been guys who will use the speedo running different size tires and divide miles by the size of the tank, not the fuel uses. So inaccuracy is ramped.

dbeer

Yes this truck got 18 - 20 mpg about 6 months ago.
I generally keep it about 65 or 70. I don't rod around.
I got 4:10 with a 6 speed manual.
Have tried several different fuels and or additives

SIXSLUG

I started hand calculating recently and I found a drop off of 2 miles per gallon from the overhead. I started fueling at a commercial dock and can let her rest and top the fuel up the filler neck to get a true starting point.
Also with my summer tires my speedo is showing a tenth mile under true distance and with the gps. This is a drag because they are the stock size. My taller winter tires are right on the money.
14-15 town, 17-19 Hiway, under 68mph.
This always seems to drop about 1 mile per gallon in the winter.

rickf

70 mph with 4:10's there is no way you are going to get 18 - 20 mpg in my opinion. I just get that in my Powerstroke with 3:55 gears. Then again I do not know the final ratio of a 6 speed but still..................


Rick

dbeer

The overhead display seems to be within a few tenths of a gallon to actually calculating it by hand. The truck is completely stock; tires, exhaust ect.etc. I use to get 18-20 empty and 13-14 pulling a load.

dbeer

If all you can do is tell me what an idiot you think I am. Then I really don't need your comments. And neither does anyone else here. I don't need a lesson on how I drive, or how to calculate mileage. And if your do not want to believe that I got 18-20mpg then that is up to you.

rickf

I don't know why you want to slam me like that but obviously it works for you. I am also a new guy here but I am also a 40 year certified master mechanic. If I wanted to tell you that you were an idiot I would have no problem in doing so and I would have just come out and said it. I did not tell you how to drive, I asked your style. I made no comments whatsoever about how you calculate your mileage. You will never have to worry about my comments to you again because I will never offer any help to you again. I am a member in very high standing on seven different technical boards and I run into your type once in a while, You want to know why but you know it all so the only answer you will accept is the one you have in your head. You are the classic "my way or no way" personality and I have no time for you.

If this is how the people are on this forum then I have no time for it.

Rick

KATOOM

Whoa..........slow down guys. rickf was trying to point out as I was too, there is lots of inaccuracy and wild spectacular fuel mileage claims but hey, if you did it right and you're getting good mileage then awesome for you. I too used to get about 20 unloaded but I cant seem to get that anymore. Maybe because I haven't taken a long road trip lately unless I'm towing something. 18-20 mpg isn't to outlandish anyways but I've seen some claim in the high twenties and even thirty mpg. Now thats just ridicules.

Mike L

Holy crap guys! - Settle down some will ya? I don't think anyone is flaming anyone here - we are all here to help. SHEESH!

Just so I can throw in my .02 here - my fuel mileage had dropped dramatically since the weather changed to winter mode and the fuel is now winter blend. This is my very first winter with a diesel motor and I can't believe how crappy my mileage is. Nothing has changed with the way the motor runs, no new parts, nothing. Just winter driving now and the fuel consumption rate is alarmingly poor.And, of course, the cost of diesel is now up to $1.02/ltr where I am. Colour me a poorer man now!

Cheers!

Mike

DodgeRam24V

i had issue with my 99 APPS, when changed it jumped up 3-4 MPG. don't know how that is related, but it is somehow.
it fixed was my cruse control too, keeping it a steady MPH that it was set at.