Cascadias with dd13 and dd15 mpg

Hey steertire. You have a dd13 and get 7 mpg w/ heavy loads? I have a dd13 and I get 5.5 or 6 at the most. I have also seen 4.9.

I have tried many things like cleaning Venturi pipe and many other. I do not iddle and most of the time do 65 mph.

What would you think it is wrong with the engine? Some would say it is the fuel quantity valve, but to be honest I do not see any problems with it.

Thanks. I'll be waiting on your reply.

 

Can’t answer that question for you. I have the DD15. My prior was DD13, it was okay but not great.

My current 2 week average is 7.6 mpg. With a mixed bag of heavy and light loads. I ran 70-75 mph on the light loads because of delivery windows. So the average could have been better.

Heaviest load grossed 79,200 from Sac to Seattle up the I-5, at 6.7 mpg.

 

Alright. Thanks for replying. DD15 has more power; therefore, more mpg. I am to the point that I see that dd13 has just poor fuel economy. My DPF filters are clean, injectors are clean, IMAP and DELTA P are clean and calibrated.

The only thing is left to test is the fuel quality. Fueling at TA instead of LOVES. In my experience LOVES has great fuel, but sometimes B20 fuel is just not good enough. You know what I mean...less ethanol more diesel.

 

The rule of thumb should be smaller engine = less power and mpg. Also, more wear and tear since it spends a vast majority of its time exceeding its real capabilities.

I started driving with a Cummins 250. There’s no way in hell I would put that truck under the loads I pull today.

 

Yes. I kind of figured that one by looking at the oil on this dd13. I had to opt to do oil changes every 10k miles and using rotella oil. It turns dark quickly while the isx 15 that I had took longer to turn darker.

 

No.

 

2020 DD15 Cascadia, 12 speed automatic, 2.85 rears. At 175K.

I cruise at 62-63mph 90% of the time most loads weighing 20-35K, or 75mph when going home. I average around 8.6mpg. I’m based out of North Carolina and typically hit up Atlanta then work my way up to Louisville or Indianapolis and run the Midwest then get back to Atlanta to go home. I avoid the east coast and northeast.

The plastic air line fittings on the air dryer like to come loose and leak air from time to time. Just check them during your pre-trip or replace with brass fittings. Other than that I do a PM every other month or around 20K miles.

My previous truck was a 2017 International with a Cummins as a company driver. 10 speed manual. Not sure on the rears. Governed at 65 and cruised at 62-63mph. Drove it to about 390K before my company sold it. At around 250-300K the fuel efficiency started to diminish drastically. Went from low 8s to low 7s by the time they sold it. Ton of bunk HVAC issues and the windshield leaked and it was a rough ride. But fleet maintenance schedules are garbage so it’s not all the fault of International. I liked the sleeper more than in my Cascadia.