Easy tests: unplug the high voltage wire at the coil (the wire going to the opti). Crank it with your car door and hood open. You hear a nice "snap snap snap" as you crank. Or have someone watch for the spark jumping. If you see/hear that, you have spark.
Next is fuel. Spray some starting fluid or Gumout brand cleaner into the throttle body. Other carb cleaners may work, but I know Gumout works great. Crank it. Should fire up for a moment. If it does, you have fuel problems. Test the pressure. Harbor Freight sells a fuel pressure gauge set for $20. Screws right on to the schrader valve on the back of the fuel rail. Crank it and go read the gauge. Must be at least 40psi.
Finally, if you installed a CAI, make sure clamps are tight and nothing popped off. No hidden leaks. Make sure MAF is not installed backwards (I've seen that before, car will run, but not reliably). LT1 cars will run with the intake elbow disconnected AND the MAF unplugged. Won't drive well. But it will start and idle without MAF (must be unplugged). Try that too to eliminate a bad MAF or intake problems.
Using these few simple tests, I can usually diagnose a no-start on a LT1 in about 5 mins. If no spark, takes additional time to narrow it down to a bad coil, ICM, or Opti. Post back here with results.
Don't just start replacing parts haphazardly. This often makes things worse because you are disturbing things that are working just fine.
Ok so its the optispark that's the problem
Therefore i'm going do this: https://www.ebay.com/itm/322692854278?rmvSB=true
Should we also change the plug wires at the same time as changing the opti ?......(i put in AC DELCO plugs and ACD wires 3 years ago, and ive put on like 30k miles since then)
Maybe just go ahead and change the ICM, and coil too while we're at this?
Im also going to need 2 new water pump gaskets (since it has to come off for changing opti) as well right?
Any other parts i need to buy/or simply just SHOULD buy when changing the opti?
Btw, I also did the "disconnect the MAF while running test": when i disconnected the MAF the car sputtered and ALMOST died when i took the harness off, but then revved right back up in a few seconds, so this means that the MAF is ok??.....that's a legit way of testing it right?
I REchecked all the connections and clamps on the CAI setup and its all tight
Any other advice/tips about what parts to get or things to do when switching the opti?
What about adding/installing some kind of "water pump drain off"......in case for some reason it might start to leak down onto the opti?
Ive looked through a few threads on the site, and ive basically listed here all the advices ive come across that im gonna need to do
But anything else you guys suggest?