Pickup - Chevrolet :: 1993 - Cranks Fine But Won't Start?

A friend is stumped by a problem with his truck, so I thought I might get some insight here. I haven't actually seen the truck, all that follows is from what he described, I'm just the messenger here.

The truck had been running fine on a used engine installed about six months ago. Then he ran it out of gas, it hasn't run properly since. It cranks fine, but won't start. He says it WILL start when spraying starter fluid into the throttle body, but only while the starting fluid is supplied. He also says he disconnected the fuel line somewhere near the engine, cranked the engine, and got good fuel supply (but no fuel pressure gauge reading). He's done some logical things: new fuel pump, fuel filter, spark plugs and wires. No luck. Figuring that he'd sucked something ugly into the injectors, he decided to replace those with no change (yes, I cautioned him about throwing expensive parts at it with no clear reason).

He reasons that he must be getting spark based on the engine running with starter fluid, and there must be fuel based on his test with the open fuel line, so he thinks it's an electronic problem, presumably the signal to the injectors. This is out of my league...and my friend is a carpenter, not a mechanic. If he could get a scanner would this kind of problem register a code?