doesnt crank when cold

This has happened twice now with my 90 2.4 mighty max in the last week.Start up in the morning is fine but after I shut it off for at least a hour I get a crank no start.Now there is spark and if use starting fluid it fires and runs for a bit.I started the truck last week with the temperature about 30 warmer than it was when it died(died between 25 to 32 degrees)and it started.A week and a hundred miles later it happened again in about the exact same conditions.I have read that the capacitors in the ecu tend to go bad in extreme weather over time.I know the fuel pump is controlled by control relay that also controls other functions.Is it fuel freezing or pump bad,I am looking for a wiring diagram of the relay to isolate power to the pump.It died leaving a job interview and had to get towed back home didnt look to good on my part
90 mighty max 2.4 179,000 miles

and it started again when it is warm out go figure

Had similar problem with mine and it turned out being the cold start circuit on the ecu. If it has not been repaired or replaced I would start with that. Any odd ball problem that comes on quickly is more than likely the ecu on these trucks.