Getting started with a 2005 Volvo with the ISX.

[Waterloo]

I'm going to throw something at you, how old is the motor's ECM? I am only saying this through personal experience. I just replaced my up until a few weeks ago working perfectly ECM. Well, I thought it was working perfectly, and according to Insite, it was. Well, she took a dump on me the other day, I had a new one, tuned by Rawze, sitting in a box at the house, so I was not stranded long and not far from the house when it failed.

The truck has been getting terrible fuel mileage since around 800,000 miles or so, but I have had two in frames in that period. Truck now has 989,000 miles on her, and I blamed these new motors and break in time.

Well I was wrong. The new ECM with the identical Rawze installed programming took my fuel mileage on paper from 6 to 9.5 mpg. This is a mid roof, no fairing or skirting, huge gap between tractor and 53' dry van, 3:42 gearing, very heavy tractor with steerable lift axle, Herd Moose Slayer Defender Bumper, Tri-Pac, Wet Kit, Lockers, and not that fuel efficient tires on the drives.

That new ECM has already paid for itself in a matter of weeks in fuel savings alone. I don't know how old your particular ECM is, but I would take a look at it it. If it is the original OEM from 2005, and still working, well it may not be. I would seriously think of replacing it with a new Cummins unit, or one of their remans. I have a reman, no issues in the past couple of weeks. Just something to think about, as I had the same Volvo in 2005, only difference, 3:55 gears, 13 speed 500 hp. I was getting consistent 7.5 to 8 mpg pulling a dry van. And I was not driving it like I drive today.