help with fuel mileage

sounds completely par for that engine and truck. ECM's lie by .5 or better so start accepting that. Also almost completely convinced that people lie about MPG and tell you about that one freak really good tank that they got good mpg on. From what I see do and EGR delete on that and lots of problems will go away.

 

Must be doing something wrong.

Been showing 7.8+ mpg this trip on paper...... 8.3+ on the computer. .been running the apu about 18 hours a day though. Uses about .14 gal per hour though.

 

2011 Prostar, ISX 400, 9 speed Eaton Fuller.
Run 65 to 68 hauling up to 46k dry van, average 33k over the last 3 months.
My 12 week average is 8.6mpg trip, 7.8 overall.
1. OCD about tire air pressure including company trailers.
2. Live on cruise control even if its for a few miles.
3. Gentle on the pedal. Don't bother trying to win a drag race off a light or ramp.
4. Never push the 'resume' button to get back to cruise speed.
5. ISX engines don't like biodiesel; use a fuel additive. I use FPPF Fuel Power.
6. Change the air and crankcase filters often; no more than 50k. The crankcase filter is under the finned cover on the left that overlaps the block and head.
7. Most important. Every day or so I pat her on the dash and say, "Good girl. "

Edit
Started using Mobil full synthetic oil and picked up a half mile per gallon with no other changes.

 

I know this is an old post but would like to have someone feed back on my fuel problem. I have a 2006 9400i eagle international with a Cat motor and i am spending waaaay to much in fuel and it is killing me. I would like to for someone to tell me what to do and I just got the truck in April.

 

What is your actual mileage? How much are weight are you carrying? What RPM and road speed are you traveling at? Do you idle a lot? Is this truck geared properly for your application? When was the last time a top end tune up was done?

 

Iam at 916898 miles and I was going to get the top end tune-up soon and I try not to run no more then 44000 pounds. I don't understand what you mean geared for my application mean?

 

If you run highway and your truck was spec'd for more city or regional then you will run high rpms on the highway all the time. The gear ratios in the transmission and rear ends are all different for all kinds of applications.

 

So what do u suggest?

 

what do you pull? flat,van,tanker? what gears are ont he rear? what size tires? how fast do you run on the freeway? from wha ti understand cats dont like high RPM. IIRC 1400 is about the highest(if i am wrong i know i will be corrected)

 

Get out of trucking, LOL!