i installed an old Sunpro power curve LED tach (CP-8098) and it doesnt work. i ran other tachs with the same wires, like an Autometer 5 inch and another Sunpro II tach, and it worked fine. but when i tried to put this LED tach, all it does does is that the 1st LED will blink and nothing else. theres night light and stuff, its just that the RPM is not being read or something. wrong wire? but its the same tach signal wire i been using forever.. help anybody?