B18c1 no start. Help!

I (hopefully) am nearing completion of what has become a 2 month project of installing a 95 GSR engine, along with all the dash wiring into my 97 Civic EX. I have tried to start it and the starter motor turns it over but won't start.

-I used the noid tester lights and they flash, so I'm assuming fuel delivery is okay.

-Spark is there, but last time I checked it , it did seem a little weak and/or inconsistent.

Could weak spark cause it not to start? I'm wondering if it could possibly be a bad ECU, the car was in a fire and the ecu didn't get touched but I'm wondering if all the heat could have still fried something.
I made it this far, could you guys please help me out, give me some advice on anything else I might check, anything at all. My car is my life, and I'm out of a job currently.

yes. check the ecu as a faulty one would cause the car not to start. secound i would check the fuel pump, timing, and the dist, all these would cause the car not to crank.

turn the key to the On position but dont start it.. does your CEL go off when the main relay clicks? If it doesnt then heck what code/codes your throwing and let us know... weak/irratic spark is usually a faulty ignitor inside your distributor