Engine/Transmission (1998.5 - 2002) Fuel Mileage

[J DeMaio]

Hi guys:



I've been running my new truck now for a few weeks with no problems. I think it will make a good truck, it has a lot of power! My question is that I've ran it enough to fill the fuel tank twice and with the calculations, it's getting 14 miles/gallon I had expected it to be quite a bit higher. I've been driving it in town some, but alot of interstate driving also. Is something wrong? Would my 285 tires affect the odometer, creating the change?



Thanks,



John

 

[KL]

John, a lot of members report a loss of 1 - 2 mpg with the use of winter fuel. Another thing you mentioned that you drive on the interstate a lot. They trucks are not very aerodynamic, so once you get above the mid 60's your mileage will start dropping.



You are also correct that your odometer may be off because of the 285 tires you have. Have you checked you tire pressure lately? This cold weather we have been having lately can effect the tire pressure, a under-inflated tire can also reduce your mileage. KL

 

[LittleM]

John,

My 01 quad 4x4 has gotten as good as 24 mpg in the summer, this time of year I'm getting about 20. I still have 265's on mine and I put a bed cover on. most of my driving is at 60 mph or less.

 

[stacerbob]

Is the speedometer recalibrated?

 

[dvaughan]

John, make sure your air filter is clean, if it is pluged your mileage will go down. Also clean your AIT sensor, if dirty can give a wrong reading to your computer, saying your engine is cold(giving it more fuel) when it is actually up to temp. Make sure your fuel filter is clean, you should change every other oil change. Check your fuel pressure , if low it can give you poor mileage. Do you have the history of the truck? Don't let it idle for to long as it does nothing for mileage. Try not to let your right foot get to heavy(ha ha)

 

[RobbyRam]

If you want good MPG'S on a Dodge Ram Diesel, and pretty fair power too, the best combo, in my opinion, and others too is:

DD2's and an EZ! It's perfect, unless you want more power only, or more milage only!

But for both together, that is the combo that works best, PERIOD! Add a DTT transmission to it, and you've broken the rules

Bob in Sacto

 

[JR2]

14 mpg is not bad. . I have kept records of ever drop of fuel that has gone in my truck and after having the truck for two years I did an average of all the info and came up with 15 mpg. That includes just about every type of driving you can do (summer fuel, winter fuel, tow light, running empty, speeding excessivly and dring 10 mph under the limit, ideling for hours, etc) except towing heavy loads. The winter fuel we get hurts the mileage, it drops to 12-14 in the winter. In the summer it goes up to 15-16 in town and 17-20 on the highway.



JR2

 

[mcoleman]

My truck usually averages around 20 mpg. With the winter fuel mix I am getting mid 18s. The wife has gotten 22 before but my best has been 21. 6. I changed my IAT and picked up mileage also.

 

[diesel DOG]

I get as high as 23 @ 50 MPH and it drops form there from drag. 65 may yield 17-18 crusing. Around town with a lead foot average 12-13

 

[DavidPope]

i got an 01. 5... and got almost 18MPG



Then I changed up to 285's right around the time winter fuel hit...



Now I am getting 14-15MPG without re-calibrating



Anyone know the % change on the speedo for popin 285's on a 4x4.

 

[FireHouseBBQ]

I just got my Ram about a month ago. I have the stock set of tires on it and also a topper and I am only getting 16mpg at best.

 

[ntillm01]

Before anyone gets feeling too bad about their mileage from a full-blown truck, ask your neighbors what their SUVs are getting and you'll feel better.



Mine? Stock 3500, no bed cover and I get pretty much what diesel DOG gets: Around 50mph cruising, 20-22mpg. On highways that I do 65-75mph on, 16. 5-17. 5mpg is the normal. The trip computer tells me where the air drag starts to pull me down. In-town, 14-15 consistently.

 

[J DeMaio]

David:



Those are the size tires my truck has on it, 285 BFG AT's. Something's telling me that maybe my speedo hasn't been re-calibrated. I've been gouging on it pretty hard lately, man will this thing fly!



Thanks for the posts!



John



P. S. If you know how to re-calibrate the speedo or see if it's been done, please post.

 

[jeepit]

Prior to my current vehicle I had a Dodge gasser 360. Best ever mileage was 11 mpg and the worst while towing was 8 mpg and not enough power to get out of its own way. With new truck I can get 20 in summer on highway, 18 city and 13 towing with what seems like an unlimited amount of power to tow up any hill. Now with winter setting in I just filled up today and got 14. 8 with last tank. I am happy!

 

[Oil Burner]

before stage II injectors i got about 17 in the winter, now with the II's I get around 19. 5 (hand calculated) in the winter. Check your IAT, it may need replaced.

-Jason

 

[DavidPope]

So does anyone know the exact difference for having 285's on there is?



I get roughly 450 Miles on 29-32 Gallons of Gas

 

[stacerbob]

speedo

Reason I asked is we often get people saying that their mileage is crap or they have a (example) '78 Chevy 3/4T 4wd w/4. 56 and it consistantly gets 18MPG or their Cummins is only getting 11 and they are figuring with the mileage that is showing on the odometer. Like it came with 245/16 and they have put 315's on. GPS for exact mileage. I think Superlift makes a box to recal the speedo, I am sure there are others.

 

[JFinke]

It belive it's around 7. 5% difference from 265's to 285's

 

[Hohn]

Originally posted by DavidPope

So does anyone know the exact difference for having 285's on there is?



I get roughly 450 Miles on 29-32 Gallons of Gas

Hopefully not gas, but diesel hehehe. .

Anyway, 265s are about 650 revs/mile while most 285s are about 625 revs/mile. That works out to a 4% correction, so just add 4% to your calculated mpg.



Justin

 

[PRout]

9-10% was a pretty close correction factor for going from the stock michelins to 285 bfg/at's on my y2k 4x4. Spent alot of time trying to come up with a good quick rule of thumb number, and using 9% put it right on at AAA's cal center, and also coincides w/ the GPS. With worn tires the number drops to 6-7%



You're probably at about 15. 5 mpg, which does seem a little low unless youre doing alot of stop & go driving, pulling some weight, or hot-rodding it. My 4x with alot of stop & go driving still gets about 17. It was worse without the timing box & injectors.