Why does my 93 Chevy 2.5 L 4-cylinder backfire and will not start?

My 93 chevy 2.5 L 4 cyl back fires when trying to start, just replaced the distributor cap, ignition wires, and spark plugs, I feel pretty good about the firing order at 1342 starting at 1 o'clock and rotating clockwise, is the timing out now? It did run although before the wires were changed