thenrie

Just wondering. I'm showing about 21mpg in town, and I can't say how pleased I am, but that is better than my Toyota Tacoma with a 2.7L 4cyl. How accurate are these fuel mileage computers in the dodges? Are they as accurate in town as on the highway?

torquefan

From what I've heard, they usually vary within a couple MPG either way on a stock truck. However, if you've done performance mods, like injectors or a chip, the reading will be pretty much useless.

You might be able to hand calculate your mileage for a few tanks, and see if the readout varies consistently with the hand calculated mileage.

Shorts

http://www.youtube.com/watch?v=8nvuEw9XcuU


Mine is off by a good 3-4mpg. I keep a hand calculated log instead.

03RAMBUNCTIOUS

^^^ haha, Mine is high by 3-5 mpg on average..

.boB

Mines reads about 1/2mpg high. I'v checked it a number of times by road miles and gallons to refill. Stays pretty consistant.

ShaneCTD600

Mine is usaually 4 high.

tlloyd

Mine is consistently 5mpg high at highway speeds and 3 to 4 in the city. I always hand calculate.

thenrie

Hmmm. I guess I won't tell my wife that. She likes the fact that it gets better mileage than my Toyota, which is one of the reasons I got authorization to buy it (she's the family financier, keeps me out of debt). But I want you all to know that I wear the pants in the house. Make no mistake about that! I make all the big decisions for the family, such as how to cure world hunger and balance the national budget, health care reform, stuff like that. I allow my wife to make the small decisions, such as where to live, what house to buy, how to pay for kids' college, etc. Works out pretty well.

I was actually concerned that doing the manual calculation would not be as accurate, because I found it extremely tedious to fill the tank to the neck. I put in an extra 5+ gallons after the pump clicked off the first time, which took me close to 10 minutes due to foaming, and I finally gave up. Never did get it up to the filler neck where I could see it. I'm supposed to have a 35 gallon tank, but I put in 32 gallons with the gauge showing 1/4 tank before the fillup. Could be I have an aftermarket tank, I guess, but it sure looks stock.

Blake Clark

I guess I got lucky. Mine is usually .5 to 1 mpg high.

Jim W

When the truck was new, my mileage gage was off by 2-3 MPG (High). I use to reset the gage every fill-up until I discover, if you leave the gage alone then it will settle down. I am now only 1/2 to 1 mpg off vs hand calculating.
You can slow down on filling up, do not run on the high setting or pull the handle all the way up. I tend to use the first setting on the handle and let the fuel run in slow. This will produce less foam and aeration of the fuel which is bad for the injectors.
Then let it shut off after first click, do this for two or three tanks fullls. This will be an average of the fill ups but this will tell you pretty close to what you are getting for fuel mileage.

Foxborough

I have been keeping track of my mileage since new and found some interesting points on my truck. The OHD is closer to the hand calculations with highway than city. I mostly drive combined mileage never totally city or highway. At the end of the year 2008 the average calculated mileage was 16.59 and the average hand calculated mileage was 17.9, that's only 1.3 MPG apart. I always assume the overhead to be about 1-2 mpg high in my truck.
FYI, When filling up the trick I just give a few clicks till I hear the gurgling or see some diesel spitting some and just call it full. I reset the overhead every fill-up I can't leave it alone like Jim W can .

bansh-eman

Have you guys ever thought of this. There was the post about the Dodges speedos being off from the factory. When going to 285 tires, it brought guys speedos to be dead on. When you calulating, you may be getting a false reading going by the number f miles if the above is true.

1-2-3

I have 285's. My speedo is off about 5 mph at 70 per multiple GPS's. My overhead mpg is dead on if you leave it for some time. It's best that you do not constantly reset it. It calculates from the moment of reset. if your already going 70 mph when you reset it, it will look like your getting way more than you really are. I use mine as a guide. I watch it and try to make it read as high as possible by driving more efficiently.

Lost Lake

These two trucks are so far apart on the Man Scale it isn't funny! That little four banger is nothing like your new six cylinder.

Expect to get 16 - 18 mpg. On good highways you can get 21 if you behave. Put a Smarty jr. on it and get 23mpg.

My overhead is 16% off. I reset it every time. What is this leave it alone stuff? You can't NOT reset it and expect it to read more accurately for the tank you are running. For example:

Reset the mileage thing and run three tanks pulling a 20,000 pound trailer up a steep hill so you get 8mpg. Now fill up and run 50mph on a long desert highway with the wind at your back. Read your mileage and it will say about 10mpg. Is that accurate for that tank? No.

You guys that don't reset are reading life averages and depending on how much city / highway driving you do, it may come close to a lifetime average. That's fine if you want lifetime averages, but pretty hard to see how you're doing pulling a mountain pass for the first time.

Mine is 16% high, and I can tell you exactly how much fuel it will take by dividing my miles by my overhead and applying the 16% fudge factor. Every time. This percentage changed when I got my Smarty and when I change tire sizes. And yes I recalibrate for tires.

thenrie

I have a Bully Dog Outlook computer, which allows me to reset the speedo for tire size. I'm hoping that also affects the mileage computer. Anybody know what sensors the mileage computer uses to figure fuel mileage and whether correcting the speedo with an aftermarket gadget also corrects the fuel mileage computer?