i disconnected the tack wire at the guage ,why does it have spark now and the tack doesnt work any help pz thanks james

Did the engine start up now? If it did then either the tack is bad or you the gray wire hooked up wrong some place. Make shur you don't have 12v power at the gray wire at either the tack end or the coil end. Take the test light and hook it to a good ground and touch the gray wire it should not light up. "BUY A MANUAL"