bad mpg's any advice?

If you want to make your boss happy, drive safe without violations, treat the equipment with respect, shift properly, try running at 55mph and maintain your vehicle. If you are only getting 4.5 mpg, have you checked the air filters? Wait until summer, winter will always result in lower MPG because cold air is denser and increases drag. IF you are really adamant about getting better MPG look into tires, you might need better traction in the winter, but you will also increase your rolling resistance which means higher MPG. If you can't fix or sacrifice any of these things, then you might just have to be happy at whatever you are getting to get the job done.

 

The ex fleet truck is a good question depending on how the engine was spec'ed

 

STexan is right on with that light foot idea. Have you tried that? Lower rpm shift points? Softer takeoffs, timing lights, the usual stuff of driving? My bookkeeper told me I spent 36% of my gross income on fuel, $60K. I'd tried for a lower number and asked him, but he said the average of 15,000 O/O's was 42-44% of gross income for fuel. That's a lot of money to leave on the table if you're pushing your rig for another load. You might or might not get that extra load, but you'll for sure use more fuel if you do. For me, it's more than worth it to minimize fuel consumption. It's smart choices.

 

All trucks hate winter fuel, newer trucks with DPF really hate winter fuel. You do what have have to do to keep fuel from freezing up north, but the new motors hate #1 diesel, and they seem to hate Power Service and Howes even more.

I had to do 2 parked regens in the past 3 weeks due to the combination of nearly nonstop idling when parked and winter fuel.

My DD15 dropped from close to 7.0 running from MN to FL., to below 6.0 at times for weeks running CA, UT, MT. Tuesday I ran I94 across MN, ND, and eastern MT. in 30-50mph headwinds/crosswinds with a not very heavy loaded reefer. This was the backside of the storm that hit Kentucky Yesterday. With all the idling and that poor motor screaming just to do 55 to 60 MPH. I saw about 4.4 MPG for that trip.

 

Get your foot out of it and try to get in the highest gear as fast as possible. That doesn't mean racing the motor what it means is bringing the vehicle up to highway speed in no more time than if you ran the motor up against the peg (governor). Shift sooner and keep the rpm's down. Try progressive shifting, that may help.

 

I have been around 6.7 on my IFTA the last 3 quarters. 97 379 horse power unknown (a lot) 650/700 range. 15 speed with 3.55 rears. I am easy on the pedal and keep it under 65.
Sheet & post 39 foot frame, occasionally pull heavy vans 38k light weight . Steel lined set up for hauling aluminum turnings.
Give it time to break in and you to learn how to drive it efficiently.

 

Do a pressure test on your air to air. Probably have a leak in your air to air. Maybe a hose but more than likely your charge air cooler. High temp silicone is a cheap fix but of course everyone will say buy a new one.

 

On a new truck it would be warranty. No matter what. It doesn't pay to short cut anything on a truck.

 

New motors take some time to break in. I drove a brand new (500 miles) KW T680 hauling dry van and it averaged around 6.8-7.2 for the first 40-50K miles. After that the average improved to 7.8-8.5 hauling a variety of load weights and in a variety of terrain in the summer months.

The adage to be "light on the foot" is the best advise IMHO. Lower rpm shift points will be best. Cruise at around 1200 rpm's with these new motors and stay light on the throttle. Even pulling grades you can find a gear that will get you up the hill in the 1200-1300 rpm range, just above the "wave" of peak torque, in order to save a bit on fuel. Ease off on the throttle as you crest the hill and allow the downhill to help be really easy on the throttle to build speed as you shift at lower rpm's.

If you have a boost gauge or scan gauge that will help give you immediate feedback on your driving habits. Try to keep turbo boost at or below 50% at all times. Using a boost gauge will help you understand how little throttle you need to give it, and when climbing hills I found that the feeling is like you are easing up on the throttle by millimeters at a time as you climb to keep boost down.

Driving efficiently will likely have minimal impact on your ability to get the job done on time.