Brainstorming has lead me here.
The fuel pump primes when key is turned to hot and then shuts off.
Since i have the push button set up, ive just been turning the key to hot and trying to start it with the button. But since the fuel pump doesnt kick back on while the key is just in hot after it is primed, the car is starting to run on only the amount of fuel that was supplied via prime. Thus, big ol' kaboom backfires.
Unless... there is something that commands the fuel pump on while the car is cranking? i havent had the chance to check the fuel pressure gauge on the rail while cranking, but as you can see in the vid below, once the key is hot, it has pressure and then bleeds off. Only coming back when i cycle the key again.
Untitled by
mickey beggs, on Flickr