1998 Astro Van starts-shuts right off

[Daddydugster]

I recently bought an Astro van from off of Craigs list, surprisingly not at all like the seller represented it (what a shock) but I needed a van and the price was in my budget. Most issues I am able to fix minus one. For the second time in 3 or so months the thing would start, run for 2 seconds, and shut off.
My buddy, a hell of a mechanic came to look at it the first time it wouldn't run, after he got off work. He asked a slew of questions and sat down in the drivers seat, cranked it, and it started right up.
It again did it yesterday and had me stumped. It wouldn't start all day but started up at dusk. I shut it off, grabbed my dogs, jumped in only to find it wouldn't start. The security light would come on, I tried the reset thing, I checked the electrical system, etc and finally, on a hunch, took the dash cover off and found a rats nest of wires from a long ago, half-azzed alarm install that had been partially removed. I cut all the wires that clearly dead ended in an empty plug, put the disemboweled van back together and it started right up. HERE'S THE THING: I have no idea if what I did is what effected its sudden return to operability or if the gremlin got tired and went to take another three month hiatus...