I just bought '09 Freightliner Cascadia with DD15 in it. The ECM report shows 6.84 mpg lifetime but we have only average like 5.5 mpg in 5,000 miles we owned, what are we doing wrong? I bought this truck on basis of better MPG. My driver has been going 65-67, I told him to drop it to 60-62 now to see what it does. Has 3.42 gears with 10 over. I didn't think the RPM it was traveling at was issue but may be wrong. Is there any place that does ECM changes to get optimal MPG but not kill power? Heard a place in Iowa does for like $300, any idea? Thank you for any input!

 

something is wrong. a buddy of mine is running a cascadia with a 435 DD15 going though pa doing 70.. he's getting 7.3mpg granted he runs light but still. do you drive yourself? if so why dont you make a few trips to see what its really doing.

 

Place you refer to having ECM done for $300 is Trent in Effingham, IL or his sister, Dusti, in Quad Cities. Give Trent a call and see what he can do for you. 217-994-1831. He does wonders for Series 60's and other engines. Not sure what he can do with a DD15.

I know one guy that has a documented history with his DD15 of roughly 8.5 mpg. He is an independent and Freightliner has him on their "slice of life" thing they have going on. Henry Albert is his name. He regularly runs around 65 mpg. Not sure how heavy, but loads are not always lite. He has done a laundry list of things for aerodynamics and such to his tractor and trailer, so that is going to account for a major reason he gets good mpg. I haven't a clue at what RPM he is running at 65 since I do not know all of his specs.

 

Your 5.5 also by ECM, or at the pump?

 

I hand calculate every tank.

 

Also I drove with driver for about 150 miles pulling heavy load and drove it like egg under pedal. Friend followed him next day and said drove like old lady so he drives respectable. All I know I have to get better than what its getting.

 

The past 2 tanks have started getting below 5 mpg and driver been running 62! He is headed to L.A. out of Arizona now, told him when he gets to Ontario this afternoon to get it serviced. I know air filter is like new but wondering if fuel filters are starting to plug up so figure services it. Arrow truck said recently serviced when I bought but I don't believe them. This was a Prime Inc truck, you think they may have had computer at low power setting? Taking to Diesel Doctor when I get in their area. BTW I had at Freightliner Monday to check make sure nothing wrong, they said looks fine in computer. All they did was check for codes, etc. They said they didn't have time to look at settings. Hopefully just setting issue and fuel filters.

 

I drive a 09 Cascadia DD15 and 13 spd with similar specs and found the mpg is about 5.5 on the ecm, but I pull heavy paper loads thru Oregon and down into Cali, lots of hills. I did notice better fuel economy in the first 10k on a service and it decreases as the oil and filters get used and our shop runs 30k on services.

 

Changed fuel filters in Ontario west, unloaded in Burbank, drover empty thru L.A. empty (horrid traffic) to Rancho Cuchamongo and thru the traffic its over 7 mpg now.

 

Fuel mileage is really pretty pretty simple. Purchase a truck that is designed to run in the sweet spot, in direct gear at the speed that you are going to drive it, then haul the lightest load that you can get. Oh and travel with the wind and down hill.
You purchased a truck that was run by a large fleet, they had it set to the lowest hp available and had the speed set at 60 or 62 mph. That is why you can't get it to the fuel mileage that they had. Besides fuel savings they know that thier (unexperienced) drivers are safer at that speed and thier shippers want them set that way, to be green.
If you want to have maximum fuel economy decide what speed you are going to drive it, then get new rear ends geared to drive at 1250-1300 RPM in 9th gear (direct), because 10 is overdrive. Now lets say 1300 Rpm in 9 gear at 62 MPH, and you still have a go fast gear to go when the law and loads allow. Your other option is to drive it at the speed that runs it in the sweet spot right now, in overdrive.
No turd-blo, air cell, air scab, majic oil additive, will get you where you want to be. Although if you are hauling a van you should be in a condo, and the ecm might be optimised but this is questionable as you don't know what the operator knows about the system that the mfg company is constantly tweeking.