Only 5.5-6.3 MPG in 2013 Cascadia

What's the trailer, usual weight and the area you run in?

 

How fast are you driving? Do you idle every night?

 

How many miles on truck. That sounds like a classic case of needs to go on the rack. (Errrr tune up valve adjust time)

 

It's an ISX they are red for a reason.
The most finicky engine ever if not kept proper they like to fail at 500,000 miles.
If your loaded to near gross weight most of the time, on factory setting you are in the right ballpark. Also your emission system has recalls right now. Going west most of the time is windy and up hill both ways.

 

Speed, weight, tires, heavy foot, terrain, engine maintenance, Engine tune, idling?

All of these things will pay a pivotal roll in fuel economy.

I have a big thirsty CAT in both my truck. 2005 Columbia with a BXS ACERT C15 and a 98 W900 with a CAT 3406.

My first truck was the Columbia. Originally a 435hp motor. I bought the truck with 825k mi. it had bad tires, a leaking CAC and I drove it with a heavy foot and always 70 - 75 mph where ever I could.

Through a combination of things,.. I got everything wrong with the engine repaired and got ahead of preventative maintenance. I got better tires on both the tractor and trailer. I upped PSI in my steers and on the trailer. I cut back my speed and use te boost gauge to adjust my right foot. I now am the slow guy in the right lane doing 63 - 65 mph. I retuned the engine and its now at 500hp set for efficiency. I bought a generator and no longer need to idle the truck.

The combination of these things Took me from 4.5 - 5 mpg,.. to now seeing 6 - 6.5 mpg. Even in the W900. And I pull open deck.

You cant run a truck hard and speed over 70mph all the time and expect good fuel economy. Its just doesnt work out. I had to learn the hard way.The difference from 4.5 to 6.5 mpg equates to saving over $20,000 annually at the pump. You guys can drive how you want. But I can think of better was to piss through $20k than out of my stacks.

Hurst

 

Agreed. I drive a 2017 Cascadia with a Detroit DD15 and the DT12 automated manual. Even with heavy 42-45K pound payloads the lowest fuel economy I’ve gotten was maybe 7.2 to 7.4 mpg. With lighter payloads my truck averages 8.4 to 8.7 mpg,although in some cases it has gotten as high as 9.3 mpg. Also,keeping up to date on maintenance and good DRIVING HABITS is key to getting good fuel economy(no playing He-Man super trucker at 70-75+ mph).

 

It depends on the gearing of the truck when dropping speed, sometime it hurts your mileage. When I decided to go to Canada with my current company, they had to drop our trucks to 65 from 70 because we were going to Quebec and Ontario. My MPG's dropped becaue our trucks are geared to run 70 @1350 rpms. Dropping me to 65 took me below the peak power band in high gear and it downshifted much sooner on the hills. And when I worked for Crete, the same thing happened. The older year trucks were geared to run at a sweet spot at 65mph, when they slowed them to 62, their mpg's went down. All their newer trucks had been geared to run at a lower speed, so they got better mpg's.

 

You're on the right track . Though we're missing some info . How many miles on the truck ? How long since the dpf was cleaned ? How long since an overhead was done ? Swap out some sensors and if necessary do the work to the dpf and and the overhead . Some other preventive maintenance with that after treatment system is cleaning your doser valves . I've had both of mine clog . A spray with brake cleaner is all you need .