Horrible mpg

[JimT]

As someone who lives in the NE, I'll add that traveling in the NE can actually be worse for your fuel economy. Once I get east of I-81 and North of I-80 I consistently see a drop in fuel mileage, regardless of load, even with an empty flatbed. The terrain and traffic does not lend itself to optimal driving techniques. Running I-84 from Scranton, PA to the MA line (a regular route for me) always results in lower fuel mileage. That being said, my 2250 can still manage 7 on an average day in this area, BUT that depends entirely on location. When I run a load out of Northwestern CT down to NYC I may only get 5.5-6.5 mpg between the hills and stop and go traffic.

Suggestions, try dropping your speed. If you have a boost gauge try to keep it 5-15psi, even on climbs. I've found I can climb most grades at a maximum of 22psi boost to maintain speeds 45-55, while 15-18psi when I drop lower. Most of the time I keep the boost between 5-10psi, operating between 1400-1600. (1500-1700 for most grades at higher boost levels). Sometimes I let it get down to 1300 before I downshift, but only when I'm running 10psi of boost and usually it's only because I'm about to crest the hill or I screwed up and wasn't paying close enough attention.

When running purely by boost you will spend part of your time driving 45mph or so up the hills, but the flip side is, with enough weight, you'll easily be able to hit 80 on the way down. The average travel speed once all is said and done for me is usually right there between 58-62mph.

I WAS getting about the same numbers you mentioned while my aftertreatment was still intact, however I was active regening, on average, 50% of each day! After the surgery I gained about 1-1.5mpg which was all getting dumped in to the exhaust.

Just for reference: I have a 2012 Pete 587, cm2250, 13 speed, 3.42 rears. Top gear is 1400 rpm at 65 mph and 1500 rpm at 72 mph. I have a mid-roof and run flatbed. Tall and light loads are worse for my fuel economy then short heavy loads. I also have a significant amount of blow-by and am currently using about 2-2.5 gallons of oil between about 10k oil changes. Just hit 550,000 miles.


What else can you tell us about your truck, trailer and operation? What kind of maintenance history? Do you have Insite? Any current problems, MIL's or CEL's? How's your oil consumption, oil change intervals, aerodynamics, tire wear? What parts of the NE do you frequent? Slowing down, limiting boost is probably the biggest thing that will help, but as Rawze said there are 1,000's of variables.