I bought a 2004.5 2500 about two weeks ago with a leveling kit and 315/70/17 on it. It has ~90,000 miles on it.

First question, since there is a tire height difference, the speedo is off. What are my best options at fixing this? I know I can go to Dodge and have it programmed, but if I change the tire height again im out the cash again. Ive been looking at programmers... but as far as what I want and what the wife will allow is another story.

Also, the fuel mileage is not what I expected. I am getting an average of 12 to 13mpg being very light on the the throttle. I picked up a bottle of Howes Meaner Power Kleaner and ran 8 ounces when I filled up the other day in case the injectors need cleaning.

Are there any sensors that may need cleaning? The mustang will start getting bad mpg with a dirty MAF.

So far, I LOVE this truck. The power of the diesel is amazing!!!!!!

 

Welcome to DTR

the dealer says they cant calibrate for bigger than 285's or so. Best bet, get your own programmer. When you and the wife are ready, do a bunch of reading, you'll get many different answers. I recommend the smarty.

the sensors dont need cleaned. Howes is a great start. check your air filter. big reason for poor mileage. Also with rubber that big, the motor is working harder to get to speed and will have worse mileage. Do you know if the ecm has ever gotten the poor mileage flash?(computer work)

 

Not that I am aware of. Hasnt had the recall "honk feature" done either.

Do 2005's have this updated program?

 

After having mine flashed it improved some. If you take it in be sure to tell dealer not to flash the transmission saftey flash. They may have you sign a disclkamer but they are not required to do it if you forbid it. Mine, after much fuel dealer work is again very poor, 18 is best empty and 8 or so w/5th wheel. Got as high as 21-22 empty prior to having injectors replaced not not very good.

 

if it had the flash, it should have a common white lable up on the radiator support, handwritten with the new flash number, and the date. Not all techs do what they are supposed to tho, so if it is missing, its only a 50 50 chance it wasn't done

 

You can have anyone with a Snap-On scan tool change for your tire size. You have to go into the ABS menu. In there you can get to the "revs per mile" or "Tire Count" section cannot remeber exact name and change the revs per mile to what you want. You would need to know what the Rev per mile are for that size tire.

Question on the mileage ? If the speedo is not correct how do you know what you are getting for mileage?

I get between 17-18 with my typical highway/around town. Better if I have more highway than around town with my 2004.5

Jeff

 

You could always buy a Smarty!! The Smarty can resize the tires in your ECM. And you can always use an extra 170 horsepower or so!! More soon with the new HOT Smarty.

 

Because the mileage will be off by the ratio of tire heights, just as the speedo is.

(315*.70*2)/25.4+17 = 34.36 in.
(265*.70*2)/25.4+17 = 31.61 in.

34.36/31.61 = 1.0869 in./in.

Since that is "unitless", you can use the ratio to find true miles driven vs. odometer miles driven, and use that value to compute miles per gallon.

 

A 2004.5 can be reprogrammed for 315/70/17 on it. Just tell the dealer to reprogram the speedo for 603 revs/mile. I think the newer trucks cannot be reprogramed for tires larger than 285's but the older ones are OK

 

ah, someone who knows exactly what's needed. great mark!