why didn't my controller mod work? (360)?

i just tried modding my controller to do rapid fire. i put the leads on the led p1 and then the middle pin on the trigger, i tested it out and it just shoots once, not rapid fire. i tested it on black ops.

i know my soldering was perfect. my controller didnt have that big metal box on the chip but it did have a crystal. my controller came with the new xbox 360 4gb . its black. was i using the wrong type of controller?