I just got my Mooneyes tach in the mail today. Before I hook it up I want to make sure I'm doing it correctly. My car has a Buick 300 with points (non HEI). The tach has 4 wires red, balck, green and white. Red is power. So it should go to the HOT side of my keyed ignitin switch. Black is ground. I can figure that one out. White is lighting. This should go to the headlight switch. Green is tach signal. This is where I'm a little lost. My guess would be to the + side of my coil. I am not 100% for sure and I don't want to fry the tach. Can anyone point me in the right direction?? Thanks as always. Todd
Some tachs can be connected to either side of the coil, if you have a ballast resistor. The - side of the coil will be bouncing between 0 and 12 volts, depending on if the points are open or closed. The + side of the coil will be bouncing between about 6 and 12 volts (if you have a ballast resistor). In either case, the frequency of the "bouncing" will be what the signal input of the tach is looking for, not necessarily the voltage level.
My system does not have a ballast resistor. I'm going to hook it up to the - side of the coil. If it is hooked up to the wrong side, will it fry anything or just not work? Thanks, Todd
Hook it (GREEN) to the (-) side of the coil ! the rest of the wires as you stated above... Crank the motor and watch the tach work as you stomp the gas pedal... Have fun....
Your system has a resistor wire it is the wire from the firewall junction block to the coil "+". Your "tach signal usually goes to the "-" or distributor side of the coil.
I stand corrected. I do have a ballast resistor. I did not wire the car and it is way high up under the dash. Anyway I ***ume it still goes to the - side of the coil?? Thanks, Todd
Just finished hooking it all up. Fired it up and it works like a champ. Thanks fellas!!! Always greatful for the help. Todd
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