Why my 94 Astro van will not fire
this generation of gm vehicles is easy to troubleshoot. the engine needs 3 things to run: compression, fuel, and spark. since you mention fire, i assume you have no spark.
disconnect any random spark plug wire and connect the end to a hei spark tester. crank engine and observe for spark. if you have no spark, disconnect the center terminal of the distributor cap and use the hei tester in the same manner. spark means cap and rotor bad or bad plug wireset. no spark means make more checks.
check for battery voltage and good ground on distributor. check for open or shorted ignition module or ignition coil windings. if power and ground is present and ignition coil tests ok, check for ignition pulses at coil primary. if you have no ignition pulses feeding the coil, change the distributor.
with that generation of vehicle, the ignition system will operate without help from the computer. don't even troubleshoot the guts of the distributor, if you change the cap, rotor, and anything else, it will be the same price as a remanufactured distributor, and might not fix the problem. if you troubleshoot a low volrage related issue (no pulses, shorted or open circuit, unstable timing, etc), change the whole thing.