I have a 1992 7.3L diesel and I just started having problems with it cranking.
In the mornings it cranks up fine but once it's a hot it won't crank, it sounds like its not getting fuel. I just changed the glow plugs and the glow plug relay but that didn't help at all

Can someone help me??

Have you recently purged water from the fuel system and changed the fuel filter? Are both batteries fully charged and battery terminals and cable connections clean? Has the engine oil and filter been recently changed?

PSDs use the Hydraulic Electronic Unit Injection (HEUI) System, so it completely relies on the oil level and condition of the oil to fire the injectors. Running the oil level low or too long can cause unusual problems. Since you have a 1992 PSD, this information may or may not be applicable to your truck. The HEUI System may have come about a year or two later.

As the name implies, the HEUI injection system uses hydraulic energy to actuate unit injectors. A PSD has two oil pumps--a low pressure lubrication pump, located near or in the front engine cover below the water pump, and a high pressure hydraulic pump, located at the front of the engine V, underneath the fuel filter assembly. If the problem persists, I would focus on the High Pressure Oil Pump.

Have you checked the fuel pump it may have given out