The Diesel Stop banner

1 - 20 of 27 Posts

·
Registered
Joined
·
505 Posts
Discussion Starter #1
Background on the truck:
2016 crew cab 6.7, auto, 4 x 4, 3.55 rear end.
Getting to work (Highway/city) on the mileage gauge, I am seeing an average of about 14 mpg. On the highway average I usually don’t see more than 16 mpg.
On the forums I’m seeing people saying that they’re getting 20mpg + on the highway. What gives?
Do I need a reflash of the ECM or what am I doing wrong?
 

·
Registered
Joined
·
348 Posts
I am in the Houston area as well and "in town" I usually average about 17.9, but it can drop to 15.x depending on traffic. I have managed 23.2 on the open road, but there are lots of variables that can affect MPG. My guess is that you are not doing anything wrong nor is anything wrong with the truck. If you are driving in town most of the time, then I would opine that your regens are happening more often and those definitely impact MPG.
 

·
Registered
Joined
·
505 Posts
Discussion Starter #3
I would be very happy with numbers like yours. How is your trucks build specs compare to mine?
 

·
Registered
Joined
·
64 Posts
I have a 2016 crew cab long box with 32,000 miles on it. My truck has 3:31 gears and 18 inch tires. I get about 17 1/2 miles per gallon at a little over 70 mph on the freeways. I get about 14-15 on city and country driving . I get 11 miles per gallon pulling a 31 foot 5th wheel and 12 to 13 pulling the four horse trailer. My 2016 gets 1 to 2 miles per gallon less than the 2011 I had.
 

·
Registered
Joined
·
1,013 Posts
My 2011 CC Dually with 3:73 gears gets a best of 17 and a half mpg on the highway at 70 mph and 14-15 in town. My old 97 7.3 got 20.7 mpg with 4:11 gears at 55 mpg, about 17 at 65 mph. I'm not complaining, but I too wonder how some of these trucks are supposedly getting 18-20 mpg driving 80 mph while I'm using the cruise control and staying under 2000 rpm. The power this thing makes offsets the mediocre mileage but I don't understand why we're not all averaging about the same mileage.
 

·
Registered
Joined
·
773 Posts
I have gotten just over 19 mpg in daily driving for mine (2011). But it's not my daily driver anymore. I'm getting around 17 mpg. I can't say anything for "city" driving, as I don't really do any. I just take my overall average.

I would say you are maybe a little on the low side, but nothing to get overly exited (or upset) about. As was said above, there's just too many variables to say whether there's anything wrong with your truck, or it's just your driving style.
 

·
Registered
Joined
·
348 Posts
I would be very happy with numbers like yours. How is your trucks build specs compare to mine?
I think they are close or maybe even the same--I have the "short" bed version with 4x4 and 3.55 gears.
 

·
Registered
Joined
·
505 Posts
Discussion Starter #8
My odometer is 50miles under the 36k mark. I took my truck in this morning for a leaky battery before the warranty was up.
I asked them to check for codes while it was there. I did though have an emissions warning light about six months ago, drained the fuel separator and it went away after two key cycles and never came back.
 

·
Registered
Joined
·
505 Posts
Discussion Starter #9
I would be very happy with numbers like yours. How is your trucks build specs compare to mine?
I think they are close or maybe even the same--I have the "short" bed version with 4x4 and 3.55 gears.
Just curious also, what size tires are you running and avg air pressure? Any mods, such as air cleaner, etc?
Trying to figure out some of the variables.
 

·
Registered
Joined
·
348 Posts
Just curious also, what size tires are you running and avg air pressure? Any mods, such as air cleaner, etc?
Trying to figure out some of the variables.
I am running the stock 20" Michelins (which I despise--3 out of 4 have been replaced due to defects) with 65PSI in each one. No modifications, but I am running a NAPA Gold air filter instead of the OEM MC because the NAPA (which is a rebranded WIX) traps more silicon than the MC does. I do use Diesel Kleen, Howe's, or Stanadyne in every tank for water control.
 

·
Registered
Joined
·
868 Posts
I'm not complaining, but I too wonder how some of these trucks are supposedly getting 18-20 mpg driving 80 mph while I'm using the cruise control and staying under 2000 rpm. The power this thing makes offsets the mediocre mileage but I don't understand why we're not all averaging about the same mileage.
My late father-in-law used to say, “There’ve been more lies told about sex and fuel mileage than anything else”. ? I’m certainly not accusing anyone here of being less than forthcoming with the truth. I just thought it was funny.
Anyway, I wouldn’t really expect our trucks to be anywhere close in fuel mileage. Driving style & habits account for most of the variation as well as things like tire pressure, load, terrain, modifications & other factors. Cruise control is not the friend of fuel mileage. The only thing it will do is hold a constant set speed. Your mileage would be better if you held constant pressure on the throttle, allowed the truck to slow down going uphill & regain the speed going back downhill (traffic permitting).
Just as a point of reference, my 4 door 4X4 dually with 3.73 gears gets 15 - 16 mpg solo (using the driver info display). I consider 15 mpg to be adaquate & 17 mpg to be really good. Towing the 16,400 pound 5th wheel in my sig, I can depend on 9 mpg & Im really happier if I just don’t look at the mpg when towing. ☺ I’ve often wondered if 4.10 or 4.30 gears would yield better mileage towing this heavy 5er. The truck tows great & I’ve had no problems.
To make a long story unbearable, I don’t think there is anything wrong with your truck. Just drive it & enjoy the ride!
 

·
Registered
Joined
·
67 Posts
My late father-in-law used to say, “There’ve been more lies told about sex and fuel mileage than anything else”. ?

This is SO spot on! Especially regarding the fuel mileage. Who cares about sex . . .?
 

·
Registered
Joined
·
505 Posts
Discussion Starter #13
I picked up my truck yesterday, and got a new battery under warranty. While it was there they checked and found no codes. They also did what they call a multi point diesel inspection and everything was fine.
The dealer also told me to make sure my Regen was completely before turning the truck off. That it would try tokeep doing it every time the truck was started, until it was complete and this would affect mileage greatly.
How do you know when it has finished? My truck will have the red/orange pop up saying that it has been initiated but turns off after about a minute. Supposedly it takes 30 minutes? Five days a week I never drive over 30 to 40 minutes at a time.
Thanks
 

·
Registered
Joined
·
505 Posts
Discussion Starter #14
I do use Diesel Kleen, Howe's, or Stanadyne in every tank for water control.
Willing to give one of these a try.
Looking at pricing, Diesel Kleen and Howe’s are the most economical, but the Howes adds ant-gel which is not needed here.
Which would just be good for water and possible fuel mileage increases? I see the DK also has cetane booster, not sure about Howe’s.
 

·
Registered
Joined
·
581 Posts
One thing not mentioned in this thread is the fuel. I have seen a significant difference in fuel economy with the quality of the fuel you run. This is true with diesel and gasoline. That said I get around 12 -13 with mine with my average use which sees a combination of stop and go, a little highway and towing. Empty truck with no trailer and strictly highway driving will get right at 20.
 

·
Registered
Joined
·
773 Posts
Maybe it's that new math.....
THIS!!! As I said, I really don't think you're that far off on your mileage. And for terrain like you drive (same for me), cruise control is absolutely your friend. It will hold the speed much better than a human foot could do. I would tend to agree in a hill area, but not on relatively flat roads.
 

·
Registered
Joined
·
2,501 Posts
I use the Stanadyne. I does not emulsify the water and try to pass it through the fuel filters for it to be burned in the engine.
 

·
Registered
Joined
·
505 Posts
Discussion Starter #18
Just an update on the mileage.
I just recently bought a set of Cooper Tires in 295/70/18. These are taller and wider than the stock Michelin‘s that were on there. But I’m consistently (2nd tank) getting about 2 miles to the gallon more. Go figure?
I assume since I have the 3.55 rear gear that it is raising the gear ratio and causing better mileage?
I have gone from 14 to 16 mpg on the computer and it should be reading opposite with the larger tires fooling the speedo.
As soon as I am on empty on this tank, I will take hand calculations.
According to my GPS there’s only a 1 mile an hour difference, being faster than the speedo.
 

·
Registered
Joined
·
2,501 Posts
The larger tires would in theory make the ratio a smaller number, i.e., 3.25 or 3.31 or similar. The engine turns less RPM to maintain the same speed.

The smaller the ratio number, the more the gear is designed for fuel mileage. The higher the number, the more it designed for torque and pulling.
 

·
Registered
Joined
·
505 Posts
Discussion Starter #20
All true, but also in theory the larger/wider tire is heavier and has more rolling resistance. Which should in turn affect/worsen mileage.
 
1 - 20 of 27 Posts
Top