Truck Repair: n14 wont start, fuel water separator, breif history

Question
i have 92freightliner with a 435 n14 that will not run it will run on ether changed the 12v fuel switch as this has happened in the past getting a code 431 breif history leading up to this truck would start to dy like clogged filter cracked filter loose retighten truck would restart almost like fuel was vapor locked. would eps make truck not start thanks in advance .have 5 n14's and have had alot sensor problems with these motors tps,speedo,oilpres. wiring harness etc. i am having better service from ddec 60 series motors  

Answer
The EPS would make it not start but a fuel restriction would make it starve for fuel ie vapor lock.Could be a number of things like plugged tank vent,fuel line crimped,cinked or "flapper" inside or a fuel water separator sucking air.TPS want make it die,just go to an idle,& oil pressure will derate then shutdown(if enabled).