Thread: Tacometer

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How do you wire in a tac? i got it from a friend and he doesn't have the instructions anymore so it has red, green, black white wires on it. i know that the green is the ground and the red is the hot ones but do i hook the reb to the fuse box, and the greend wire to the chassy, but what wire goes to the distrbutor. it will be hooked up to a small block chevy 327

Thanx Cd

Not all tachometers are the same. It might be helpfull to know what brand you have, then someone might have the installation instructions for that particular unit.

Some thoughts. First, unlike house wiring, green is not necessarily ground. More often, while not always, in automotive it is the black wire. Likewise, the white MAY be for an internal light. Look around the housing to see if there is a "switch" of some kind for selecting the number of cylinders. If you have dual points typically (meaning not always) you would chose 4 cyl for an 8 cyl engine. Look at where the wires attach inside the housing (if there is one). Hopefully one of the connections is marked "S", that would be the one that goes to the "-" on the coil. The Batt or "B" terminal would go to the "hot" side of the ignition switch, or a switched source of power. Sometimes the lead from the coil will require a filter to inhibit cross-over signal interference. Again, that would depend on manufacturer. Hopefully it's not one of the old style tachs that require a remote sending unit and you only have half of the system.

thanx bob, its a newer tach. i know it don't need a sending unit. umm it has a switch so you can choose 4, 6, and or 8 cyl. im not sure if the manufacturer is stamped on it. but when i get it back from my best friend tomarrow i will look for a manufacturer.

Thanx bob
Cd

Green goes to the terminal on the coil that goes to the distributor. Black is ground. White goes to headlight power so it's lighted when you turn the lights on, and the red is 12v power (only on with key on.)

That's the way they usually hook up. Good luck!


MMMM.......TACOmeter

FYI= tachometer

Green wire: Coil negative. White wire: Dash lights(the ones the dimmer dims) Black wire: Chassis ground(any bare metal in the car) Red wire: 12 volts positive switched. That works on Autometer, Sun gauges, Autogauge and NAPA gauges. If a wire is marked "S" that is the signal wire( coil negative). You did not mention the car it is going on, be careful of some newer cars that operate with crank triggers and coil packs, really complicates the install. Remember, FUSE power leads and use grommets when going through metal. Christopher.

im putting it in my 81 chevy pick up so i can see what this new engine is doing. Ya i know i miss spelled it nick. i was in a heary and after i posted it i was like sh** oh well its all good.

Thanx for all the help i will put it in when all this snow melts we got hit hard today so it wont be in tell next weekend or so. Thanx again

Cd

well i got the tach in today and works great, thanks for everything guys. Cd