Cummins N-14 power????

I have one like yours only a year newer that I bought in January and it always has pulled like a mule , I cruise at 1500 to 1550 and downshift about 1300 .
Fuel mileage sucks ..never over 6...but I'm always heavy and my trailer grabs alot of wind .
Other than mpg I've been very happy with it .

 

Does it have a boost gauge,if so what is it under a hard pull.You can tell a whole lot from that.Check air cleaner restriction,fuel filter also. Owned an N-14 500 for a long time,ran great.

 

First thing is to check maintenance items that affect performance, i.e. filters. Next is to verify the intake and fuel system doesn't have any issues like a torn CAC hose or cracked fuel line that is sucking air. After that is verified then you can dyno it and verify performance but don't compare it to another truck/engine combination unless everything is the same, you'll prejudice yourself and one or the other will never perform "right".

 

i've seen fuel pump drives being worn out on these. with lots of hours those ecm's can cause issues with wearing out injector driver transistors too, i'd check for proper fuel pressure first, 25 psi during cranking, 120 psi at 1200 rpm and 150 to 180 psi at governed rpm.

 

they also have a fuel supply fitting check valve before the fuel pump, they sometimes get gummed up

 

Yes,run the rack,easy to do,get that correct,so you have a starting point.My 95 N-14 500 would pull 37-38 psi of boost,depending on the atmosphere.Whenever my boost would start dropping,first thing I would do is change the fuel filter,99% of the time that was the problem.No fuel,no boost.

 

I changed an injector, which was working intermittently (somehow my mechanic spotted it), did valve adjustment and gained about 0.7 mpg. Heavy 6.5 mpg, under 20k about 7.5 mpg running 65-70 mph with dry van