Before putting more work and money into this issue; it would be important to sort out whether this is a fuel problem or an electrical problem. The first thing I would do is to replace the fuel filter. If this doesn't fix it; disconnect the fuel line at the engine, run the fuel line into a catch can; turn the key on to the point where the dash lights come on, and see whether a stream of fuel is pumped out of the hose into the can. If there is no fuel flow, and you do not get power to the fuel pump; the fuel pump fuse, fuel pump relay, or fuel cutoff relay may be defective, so I would then replace the fuse or one or both of those relays. If that doesn't fix it; I would then replace the fuel pump wiring harness (this is a known problem on this model). And if that still doesn't fix it, I would replace the fuel pump. I'm posting a link to a photo of the fuel pump relay below.
But if you do get a strong stream of fuel from the fuel line; I would first check to see if there is a strong spark at the plugs when the starter cranks (by attaching a plug wire to a clean spark plug, and clamping the threaded part of the plug against the metal of the engine). Try this on several different plug wires. If you don't get a steady stream of sparks from each plug wire; I would check to see whether you get full battery voltage at the battery terminal of the distributor cap. If the voltage at the cap is more than 0.5 volts below the battery voltage while the engine is cranking, you may have a bad ignition switch or a bad neutral safety switch. If the distributor is getting full battery voltage while cranking, I would replace the distributor cap and rotor; and install a new set of spark plugs at the same time. I would also test the resistance of the plug wires (should be less than 1,000 ohms for each inch of wire length) or just replace the plug wires.
If you get strong sparks at the plugs; I would then get a solenoid test light; and test for voltage pulses at the injector while the engine cranks. The 350 and 454 engines in 1989 both had throttle body injection, so there is only one injector on that motor. It usually is not necessary to rewire the injector; but the wiring connector at the injector can become loose or corroded.