MPG HELP!!!

So I just bought a freightliner century 07 model series 60 14L. Had overhead run because I knew nothing about the truck and hoped my mpg's would come up. Well I'm still stuck at 4.8-5.25 no matter how differently I drive the thing. Any and all advice would be helpful for me to figure out what to do next. Also it falls on its face when it sees a hill.

 

I would HIGHLY recommend talking to Rebel127. My Century is Identical to yours.

DD S60, EGR, 14L, 13 spd, 3.42 gears, LP 22.5 pulling a dry van.

http://www.thetruckersreport.com/tr...-wheelers/198348-s60-14l-ddec-v-egr-mods.html

http://www.thetruckersreport.com/tr...01716-its-amazing-little-things-how-they.html

I have seen about a .4 mpg increase so far since Rebel127 did my truck.

As to running in the hills. OMG. It's not the same truck. I set the cruise at 1650 RPM and the hills just disappear behind me.

I am most interested in seeing how replacing that kinked fuel line is really going to benefit me. I still have one more to replace or else I am just going to pull the 90* elbow and put in a straight fitting on the DAVCO inlet side to straighten it out.

 

Specs of the truck?

 

I found my specs on the passenger side dash.

There's a panel just below the fuse block cover that comes out and there is the spec sticker.

 

14L 60s on 22.5lp 13spd 3:36 in the rear midroof xt 242' wheelbase

 

How much weight do you pull, how much do you idle, etc. how much city driving, how much do use cruise control, etc. those are all huge factors in fuel mileage

 

Those are good questions, when I do a lot of hills out west, my mpg sucks, head winds make me lose mpg, it all adds up.

Getting good fuel is another consideration. I always jack up my fuel with a cetane booster, it helps since I had my HP turned up as high as it goes and turned off the progressive shift in the comp program. Which by the way, is what companies and some people do to increase their mpgs, turn down your hp and turn on the progressive shift feature, which forces you to shift at a lower rpm, nearer the bottom of the range.

 

Start looking for air leaks, first on the exhaust side (EGR cooler, exh manifold cracks, EGR crossover tube couplings) then on the intake side (intake boots, CAC, and so on).

 

does a low rear end axle ratio give better fuel mleage?

 

I found my air leaks on the CAC boots using windex sprayed on them. Just set the truck up on high idle. It'll blow big bubbles with the right mix of soap....