93 Astro Fuel Problem T.B. bad?

Hope some one can help me.
Just bought a '93 4.3l with throttle body unit, 123k on the clock. (Vin=Z) The seller said it ran fine, he parked it, it wouldn't start the next day but it fires on starting fluid.
The van has sat for two years. I figured it's just another bad fuel pump, and replaced it, added fresh gas, no crud in the tank. Still, no go. Replaced fuel pump relay, and hooray! fuel pump now runs. Still won't start. The cranking oil pressue is good. It fires on starting fluid.
I figure the fuel filter(s) are next thing to rpl. Any ideas about what else may keep fuel from flowing in a throttle body unit? Can they be rebuilt with a kit like carburators? Should I bleed the gas lines? Any help will be greatly appreciated!

When it cranks, are you seeing the injectors fire?

Could be a bad ECM....

Ouch! the ECM - not a cheap part. The only other thing I can think of related to a lack of fuel pressure is the fuel injector pressure regulator. (not a particularly cheap part either)
I'd give a new fuel filter a shot first.

93 is still OBDI, right? Have you tried shorting the two pins in the diagnostic connector and reading codes off the check engine light?

I am somewhat skeptical that the fuel filter could become clogged so much that it would prevent the engine from even hitting.