Disappointing highway fuel mileage

[jacknife]

Are kidding ? 75 mph and *****ing about 19 mpg ! At that speed you should be jumping for joy !

 

[Grizzly]

My truck and 5th wheel loaded for our recent trip to Alaska weighed just under 20,000 lbs. We drove 10,500+ miles at no faster than 65 mph. We drove much slower in Northern BC and the Yukon as road conditions and speed limits dictated. Our hand calculated round trip average was 10.58 mpg. The overhead averaged 12.9 mpg. I did use my Transfer Flow 65 gal fuel tank/tool box combo in the Yukon where diesel was the most expensive. I refilled the Transfer Flow in Anchorage, which had the least expensive diesel in Alaska, to get through the Yukon on the way home. The cheapest diesel was here in Albuquerque at $2.32 per gal. The most expensive was at a place between Whitehorse, Yukon and Dawson City, Yukon at $1.90 per liter, which equates to $7.18 per gal, Canadian.

Sure wish I'd have got 19 mpg. george

 

[Doubleclutch]

Nice pics, Griz.

 

[zb39]

I'm lucky if I get 13 on the highway.................no kidding. But I didn't buy it for that.

 

[Sierra1]

I've had this 2015 2500 for approx 9 months now, 12k miles on the odometer. Most all of my driving is around town and towing. Just yesterday we left for our family vacation so we got our first true highway miles.

Drove from Maryland to Pigeon Forge, TN with most of the miles down RT81. Drove between 70 to 75 mph on average, not any higher. Cruise rpm was right at 1650 rpms. Had the cruise set on when I could.

Trip odometer said right at 500 miles till we pulled in, low fuel light had just come on. Filled up and hand calculated which came up with 19 mpg.

My old 2003 would get 20-21 mpg on highway...and that was with 3.73 gears, shorter factory tires and probably turning 2200 rpm at 75 mph.

Also, I sure wish Titan would offer a larger tank for the short bed crew cab. I kinda miss the larger tank my old trucks long bed had.

I have a truck similar to yours 2015 Cummins/Aisin CC, LB, 4x4 and got 22.1 MPG from Kansas City to Florida, and 20.9 MPG on the way home a different route that took us through the mountains of Arkansas. I had about 4500 miles on mine when we left out, and I couldn't have been happier with the mileage considering we ran anywhere from 65-80 MPH the entire trip with 5 of us on board, and a bed full of stuff. I have a soft bed cover over mine which might account for a little of the mileage, but otherwise I think we're close to the same. Since day #1 I've been told I have a happy motor as far as mileage is concerned. When I had about 3k miles on it I hooked up 28k pounds to the back and drove the truck like I stole it every chance I could hammer down. Although the trip was not very long (~65 miles), I think really getting after it with that kind of weight help to expedite the break-in process some. Every week I routinely tow ~10k pounds hauling water, that trip is about 5 miles tops. This is my third Cummins powered truck, and I can say with certainty that the other two didn't get good mileage till they had about 30k miles on them. For sure switching over to full synthetic oil helped smooth out the motor, and really working it when I had some weight behind it didn't hurt either. This new truck seems to get clogged up when I just ease around town for any length of time....I also burn through the DEF a lot quicker. I'm highly considering buying a Race Me Ultra so I can delete the emissions on the exhaust and motor. I think I'm going to stick with the OE downpipe and tailpipe, and only get a straight pipe to replace the filters. I think freeing up the exhaust will really help things out. I doubt I'll run the tuner much over the first power level as I've learned my lesson with messing up the transmission and motor running the tune too high on some of my other trucks. The Race Me Ultra allows you to run stick power levels and delete all the emissions. The only mod I have right now is a K&N filter in the OE airbox, and I removed the foam from the intake silencer.

 

[Cummins12V98]

Sierra1, repeat after me....."I am my own warranty station"

 

[Grizzly]

Nice pics, Griz.

Thanks Doubleclutch.

george

 

[AH64ID]

The only mod I have right now is a K&N filter in the OE airbox.

Why ruin a perfectly good truck/turbo with a crap filter right off the bat??

I don't think there is a better filter available than the OEM filter, and that is true for all 03+ trucks with the stock airbox.

 

[Mingoglia]

I've also found now that I've hit 10k miles my mileage has gone up a couple MPG. My heavy foot and 4.10 gears still don't yield "great" mileage, but it's all relative.

 

[pjorlando]

Took mine on a nice long run over the holiday weekend. From Long Island to Washington DC. 2 nice things, the first being diesel at 2 bucks a gallon in New Jersey, the second being 20mpg while cruising at 70 to 75 mph, I do use the cruise control , when I can. My '06 never saw better than 16 on the open road. I can't and won't complain about the improved economy I am seeing.

 

[PGAdams]

just finished a trip to FL from GA. New 2015 3500 3.42 rear. about 1700 miles on the odometer. 20mpg 13.8gal, 75-80mph with a/c.
the onboard computer read 20.9. calculator computed 13.8 gal, 268miles
On the return trip yesterday, into the North wind better, 19+mpg.

 

[Cummins12V98]

Took mine on a nice long run over the holiday weekend. From Long Island to Washington DC. 2 nice things, the first being diesel at 2 bucks a gallon in New Jersey, the second being 20mpg while cruising at 70 to 75 mph, I do use the cruise control , when I can. My '06 never saw better than 16 on the open road. I can't and won't complain about the improved economy I am seeing.

You have 3:42's?

 

[rrl989]

Took mine on a nice long run over the holiday weekend. From Long Island to Washington DC. 2 nice things, the first being diesel at 2 bucks a gallon in New Jersey, the second being 20mpg while cruising at 70 to 75 mph, I do use the cruise control , when I can. My '06 never saw better than 16 on the open road. I can't and won't complain about the improved economy I am seeing.

Other than a few spots on the NJT, where do you ever get to cruise at 75 mph on a LI to DC trip? I'm guessing you're reading the lie-o-meter because no 8500 lb DRW gets 20 mpg at 75 mph speeds, not even my old 12V.

 

[2rrRAM2nv]

I'd be happy as heck. I commute to my work apt (145 miles 1-way) doing 76 on cruise, and currently, I get 16.5 OTW to WY and get almost 18 OTW home from WY. mind you, I do realize I'm hauling butt so MPGs are gonna suck, so I guess I can't complain. I haven't bothered with hand calculate since I didn't buy the truck for MPGs, I bought it to do truck stuff. If I wanted MPGs, I would have bought a 1500 ECOdiesel.

 

[pjorlando]

I guess that my lie-o-meter is wrong. When calculated by gallons used into miles driven, I actually saw 18.9 mpg, average. And yes, I did cruise at lower speeds during my trip. Living out in Suffolk County, going 70 is slow on the LIE. My trip was done leaving NY at 0300 in the morning. No traffic, and yes, cruised right through the BQE, Staten Island, and NJ. The only place I slowed down was in Delaware. I can't explain my good fortune, only that it surprised me and put a smile on my face.
I too have owned a first gen, 12 valve. Lucky to get over 65mph, fuel economy wasn't much more impressive. 10 to 12mpg. My second gen did better at 16mpg, it was a 12 valve also, P-pump. Both of my 3rd gens saw 12 to 16 on a good day. But I'll stand by this 4th gen as the best. I'm getting old(soft and lazy) I do appreciate the finer features this truck has. The little extra fuel economy is a plus. IMHO.

 

[rrl989]

I guess that my lie-o-meter is wrong. When calculated by gallons used into miles driven, I actually saw 18.9 mpg, average. And yes, I did cruise at lower speeds during my trip. Living out in Suffolk County, going 70 is slow on the LIE. My trip was done leaving NY at 0300 in the morning. No traffic, and yes, cruised right through the BQE, Staten Island, and NJ. The only place I slowed down was in Delaware. I can't explain my good fortune, only that it surprised me and put a smile on my face.
I too have owned a first gen, 12 valve. Lucky to get over 65mph, fuel economy wasn't much more impressive. 10 to 12mpg. My second gen did better at 16mpg, it was a 12 valve also, P-pump. Both of my 3rd gens saw 12 to 16 on a good day. But I'll stand by this 4th gen as the best. I'm getting old(soft and lazy) I do appreciate the finer features this truck has. The little extra fuel economy is a plus. IMHO.

Recently moved out of Suffolk to FL, and hated the southern route to DC and switched to the GWB instead. I can get my 2014 lie-o-meter to average in the 20's, but truth is 15'ish mpgs.

 

[pjorlando]

Funny, I lived in Florida, moved back home after 21 years away. I did miss the snow and my wife wouldn't raise our kids down there. Education system isn't as good as here. There is hope, I will move again, south when my second retirement comes due, this time not as far south. I can't take the constant heat and humidity. I have too found the route through SI to be a PIA. I've often use the GWB, but the Cross Bronx can be a mess any time of day or night. I travel upstate frequently and try to stay as far away as possible form the city.

 

[rrl989]

Funny, I lived in Florida, moved back home after 21 years away. I did miss the snow and my wife wouldn't raise our kids down there. Education system isn't as good as here. There is hope, I will move again, south when my second retirement comes due, this time not as far south. I can't take the constant heat and humidity. I have too found the route through SI to be a PIA. I've often use the GWB, but the Cross Bronx can be a mess any time of day or night. I travel upstate frequently and try to stay as far away as possible form the city.

LI continues to lose the jobs, mine moved to FL. I bought my 2014 3500 to do daily battle on the LIE as I did for 16 years in my 98 3500, now I have all the 4x4 and "winter" options which are useless here in FL. With almost one year now here in FL, I miss "home" and the ferry over to CT for NH and Maine trips. Gave up my camper already, now the truck is going too. Good luck.

 

[GCuzzy]

Were you towing, sounds not. I think you're engine & transmission needs more miles. At 63 mph I get about 24 mpg after 70k, I too am planning for a larger tank.

 

[TNT]

My 12 dually gets 12 if I baby it, 10 most of the time, and 6 when I tow my 48' enclosed trailer at 70 mph.