Cummins N14 boosting the power/filter vac #'s

The new lines I had made are larger than the old ones. 1" in diameter with a fabric braid on it.

10 micron filter. I was told by Davco I need a 7 micron. Have not confirmed it yet with Cummins. The Davco came with a 25 micron filter, will give that a shot and see what happens.

 

What is the factory suggested micron rating? I only went this low because the folks at Davco said 7 micron was the OE spec. I'm guessing they are way off.

Truck definitely ran better today, not a huge difference but noticeable. About 9/10 LBS on the gauge at idle and no more than 15 while coasting or running the jakes. Actually ran the hills OK.

Had one last line made today, the one from the cooler plate to the filter head, and the #'s at idle are finally in the green! 5LBS idle and no more than 10 while on the jakes. Big difference from 15 at idle and off the gauge while on the jakes.

Any guesses why the #'s go higher when you're off the throttle?

 

Got my "rebuilt" cooler plate from N14parts.com and my check valve is on the way.

I'm looking for a fuel system diagram for the N14. I'm having some trouble trying to figure out what is a fuel line and what is an air line(replacing all the fuel lines). It appears the air compressor and fuel pump are the same unit on this truck...Is that right?

 

Wondering if anybody has advice for unscrewing the cover for the screen on the fuel pump right behind the solenoid? It has a notch for a flat blade screw driver and I just can't remove it.

With all the fuel lines on the entire truck changed as well as the cooler plate there is no change. Still a dog and still high #'s on the gauge.

 

Finally got the stupid plug out that the filter screen hides in. The old filter had completely imploded on itself. The plug was stuck in there BAD and had likely not been removed in many years. Not sure why Cummins put a screw driver slot on that thing instead of a bolt head! My mechanic welded a nut to the cap and that did the trick.

Installed the new filter and there is no change in performance but now the truck is really acting up.

The fuel filter vacuum gauge "hunts" at idle now ever so slightly but more or less stays right around where it was before.

The BIG thing is the truck is having trouble starting, fires right up then stalls out unless you hold the throttle down and help the truck clear its lungs out. Also at 1000-1200 RPM's the truck shudders if you're trying to pull pretty hard, seems to do that intermittently. Last but not least the "Stop Engine" light came on periodically this morning and I'm getting a code 254 which is a problem with the circuit for the shut off solenoid.

By any chance when my mechanic welded the nut onto the cap for the fuel pump screen could that have fried anything in the ECM? I made sure he disconnected the batteries before welding.