b18coupe

when i tried to crank the car from the inside it wouldn't turn over, but when i left the ignition on and ran a wire from my starter and touched it to the postive battery terminal it fire right up, what could cause the motor not to fire when i turn the ignition from inside the car? another problem when i had the motor running i let it idle for a few then brought the rpms up when i done that the number 1 spark plug wire blew off the spark plug.