If you have fuel in the engine valley. Then it is injection pump related. Maybe the hard and soft 3/8” hose going under the intake to the fuel filter but I have never had one of those leak on me.
There is a 1/4” hose going from the fuel filter to the IP. Hopefully, your is cracked or loose. Which is the easiest and cheapest fix. Pull the air filter, get a cushion from a lawn chair, put the cushion over the hood latch, radiator and engine. Lay down on the cushion and work your hand along the hose all the way to the IP feeling for leaks.
If that came up dry, use mirrors, lights and magic to look at all 8 injector lines at the IP for leaks. Normally, only the ones on the bottom ever seem to leak. I can’t remember if those are 5/8 or 11/16 sized fasteners. Whichever the lines at the injectors are, the ones at the IP are the other. Use a crowfoot socket and a long extension to tighten them up if leaking. If not leaking, leave them alone.
The only thing left and most likely cause is the IP throttle shaft seals. There is one on each side. If that is the leak I suggest an IP replacement. Yes, supposedly you can do the seals on the engine. However, if those seals are dried out and leaking. What about the seals inside the IP which are the same ancient age?
