Cummins N14 Long Crank Tried the Norm

Filter base could have a crack letting air in.
Could be the fuel filter o-ring is bad.

 

I've had bases with a crack that didn't leak fuel. It was a remote filter base.
Does your fuel line connection at pump have a seal?

 

It still could be a fuel pump. The pump will start to wear enough that it struggles to pull fuel and develop enough pressure at crank to fire it up. Once running at higher rpms the wear is insignificant and it runs fine. I would still do a mechanic pressure check to make sure. To rule out your fuel lines, the easiest way is to make up a test line and connect it right to the pump inlet at the filter base and run the line direct into your fuel tank. Get it running, then shut it down and let sit over night and try again the next day. If it fires right up, then you have a bleed down problem in your lines, if your long crank is still there, then pressure checks are next.

 

I was going to suggest the same thing. My two n14 absolutely hate Baldwin fuel filters. Takes forever to crank with them
Edit: forgot to add that I suspect their oring let's air in

 

Heavyd nailed it. It's easy to make a bypass hose. I used clear plastic hose with hose clamps holding brass fittings on the ends. Not much pressure in the feed line.

I always used fleetguard fuel filters on my last truck. It would always crank a little longer when the temperature was below 20 degrees, even with a block heater overnight.
My "new to me truck" that's the same as old truck (99 fld120 with N14+) has the Davco fuel filter. Much easier to see if there's a bleed back of fuel from filter housing.
I've also had a bad o-ring where fuel line fastens to the filter housing. Depends on style of fittings on fuel line.
Good luck

 

A defective oil pressure sending unit,or corroded conections can cause long crank on N14. Had 99 Pete with 3 senders on it. 1 was cracked at terminal. Truck took 20-30 seconds cranking to start. New sender, 5 seconds to start.