You should begin a systematic troubleshooting approach to your problem. Get a spark tester, the kind that puts a load on ignition system simulating compression pressure, and a fuel pressure gauge.
Also check for codes, the 3 ignition biggies dtc's 16, 41, & 42, don't light the check engine light but will keep car from running. On your 93 you can use a paperclip on the dlc to check for codes. Connect terminal A & B of dlc turn ignition on and codes should flash.
When car won't run, first test for spark. If good spark, attach fuel pressure gauge and check for 41 ps1 or more at key on prime.
If no spark, go to sticky threads of this section and open the diagnosing the optispark tread. Watch the video and run the tests. shbox.com
also has opti testing, as well as coil testing.
and yes, use wiring diagrams in service manual to check grounds, power supplies, connectors, connector pins, etc. Opti wire harness, which runs from opti to passenger side of intake manifold, is a prime candidate.
Service manual, in wiring diagrams, will have component location listed to help you find those pesky grounds.
Go to 4th gen section. Look for thread titled "GM service manuals". Open it, click link, download 93 factory service manual. It will have wiring diagrams, troubleshooting help, a ecm connector symptom chart, driveability and emissions section.
So your task is to find out if spark or fuel pressure is missing when car won't run. When you find which one, report back and we can take it to the next level.