does it have a block heater? if so plug it in for an hour or two and see how it starts.
if it fires right up then it maybe glow plug issues. easy place to start.
1988 FORD 4x4 Ranger. swapped in mis-match hodge podge of HMMV-CUCV 6.2 stuff / 4l80 into ford np208. All that crap is riding on ford 60's spinning 305 tires on up to 44's depending on the days menu.. so how ya like me now?