Follow the fuel. Start at the tank make sure you have good fuel in it. Make sure the filter has fuel to it , then make sure that the fuel is getting to the pump. then see if the pump is pumping fuel to the injectors. If no fuel to the injectors and you have fuel to everything up to the pump and the right pressure to the pump your pump is shot. Also don't be afraid of ether just don't abuse it. just a sniff. disable the cold start system and give it a quick shot in the air tube at the filter. that truck should not need anything as a cold start aid in florida at that temp. A cummins will start at just about any temp when all is right. vp44 pumps are known for failure. If all that checks out it may have a bad crank sensor you may need a good scan tool to help your diag. Diesels are simple