Before you continue, your 7.3 IDI is mechanically injected, therefore you will NOT have an HPOP for the fuel injection system. My apologies for wasting your time.
I would still focus on the Fuel Delivery part of the Fuel System for a No Start and drain the fuel bowl & change-out the fuel filter and check the mechanical injector pump from pump-to-injectors for signs of fuel leaks.
Check these Links to see if any apply -
You don't have to drain the HPOP, just make sure it is Full.
The HPOP is located on the Top of the engine in the Center, Front between the cylinder banks and vertically inline with Engine Front Cover. The Oil Fill is a small Plug with a Hex (Allen wrench) in it on the Top Cover of the HPOP. It is about 5/8" in diameter. Mine likes to fall off the wrench (get a replacement here -http://guzzle7pt3.com -- Ford does not sell one). They are also good for a O-rings and other Diesel Stuff.
The "Full Level" is usually about 3/4" below the bottom of the Threads of the Fill Cap. Check it first to see how low it is. Sitting for three years it may have leaked down into the crank case. Fill it to the bottom of the threads just to feel good about it. In fact, if it is really low or even empty, that could very well be the reason it won't start because this is the source of the Oil that 'operates' the fuel injector (at least on the PSD).
1997 Cargo Van. 7.3 PSD - 185k miles. Stancor GPR, IH Waterpump w/ Filter.
Last edited by stever88; 03-06-2019 at 12:01 PM.