Common software for all engine computers is the shut off of injectors to clear flooding.
Turn key on
Push gas pedal to floor, hold it there, this sends >4.5volts to computer from TPS(throttle position sensor), with no crank turning pulses(CKP) this initiates the "no injector pulse" routine.
Keep gas pedal to floor and Crank engine
Engine should not fire, it is getting the spark signal from computer but there should be no injector pluses so no fuel/air mix to ignite.
If it does start to fire then somehow fuel is getting in
Getting spark and getting spark at the right time are two different things.
If you have a timing light check #1 spark against the TDC mark when someone cranks the engine.
Also, as always, recheck firing order twice, been doing wrench work for 30 years and still get it wrong, lol.