ignition coil -> spark plug

[nick753159]

well, I'm trying to wire a new ignition system for my gun, and its not working out that well.
the system has a 9 volt battery, automotive ignition coil, and a spark plug.
I've ran a plug wire from the plug to the center plug on the coil, and then positive/negative wires from the coil to positive/negative on the battery.

i took this off a diagram i found online somewhere. i was planning on wiring a switch in, but first i wanted to test it, so i just quickly touch the positive wire to the battery terminal, but it doesnt do anything.


any help?


EDIT: I believe ive solved the problem. 1 wire also needs to be ran from the spark plug body to the battery. ill check on that tomorrow when its light out.
anyone know why that would make it work?

[shud_b_rite]

Because your sparkplug needs to be earthed. When the plug is screwed into the engine head the threads of the plug are toughing the engine (which is connected to the negative of your car battery) and the ignition lead provides the high voltage which bridges the gap to the earthed side. If your plugs are not earthed then the spark will have no where to go so nothing happens.

[TurboSuper]

Also, it probably won't make a spark when you touch it to the battery, but rather when you disconnect it from the battery.

[Matheusilla]

You also need a capacitor. I'm pretty sure it gets placed between the coil and the battery on the negative side (earth side, same as spark plug ground). Also, you'll probably need a bigger battery for the automotive coil to work.