I got a 81 firebird with a stock tach that reds out at 6000 and im very challenged when it comes to the wiring part of the car, i want to put an aftermarket tach in it and i dont know how.The tach has got 4 wires, red, black, white, green, i know ones goes to tach on the distributor cap , one would go to a body ground, one to a power wire, not sure on the last one and wich wires will do what. is it posible to disconect my factory tach and use those wires ? and would they be the same colors....thanks for the help:thumbsup:

I got a 81 firebird with a stock tach that reds out at 6000 and im very challenged when it comes to the wiring part of the car :confused: , i want to put an aftermarket tach in it and i dont know how.The tach has got 4 wires, red, black, white, green, i know ones goes to tach on the distributor cap , one would go to a body ground, one to a power wire, not sure on the last one and wich wires will do what. is it posible to disconect my factory tach and use those wires ? and would they be the same colors....thanks for the help


:thumbsup:

One might be for the illumination. What kind of aftermarket tach are you installing. You can probably get the wiring info from their website.

Green is the signal from the coil.
Red is the 12V hot when key is on.
Black is ground.
White is illumination.

I'm not sure how the wiring on a 2nd gen factory tach connects, but likely you have three wires to the tach, probably colored as follows:

white = signal from coil
pink = 12V hot key on
black = ground

Your OE tach probably has a bulb above or behind for illumination, with a gray feed wire and a black ground ending in a bulb socket.

here's an Autometer installation PDF; the wiring is pretty standard for aftermarket tachs in general.

http://www.autometer.com/productPDF/1077B.pdf

I believe white is the sender wire, for a factory tach.

On your aftermarket tach:

Black is ground.

Red is power, connect to IGN terminal on fusebox.

White is "Illumination" you can connect this to the tachs red wire (light will be on whenever engine is, at full brightness) or to the cars "illumination" circuit. (the tach will only be lit when the headlights are on, and will dim when you turn the headlight switch) At least on Firstgens, this is the gray wire in the dash harness. The easiest place to splice into it is the wire going to light the heater controls, or in an automatic car, the wire going to light the shift quadrant lights in the console..

Green is the wire that needs to go to the coil.

I merged your 2 identical threads posted about 12 hours apart.

It is neither helpful nor desirous to post the same question multiple times.
(wow, I used a big word, hope I speeled it right!)

Thanks alot guys i dont think ill have a problem with the install anymore.Sorry about the double post jim im on dial up so my puter goes so slow sometimes, i pushed the stop button and pushed submit again ,and 2 threads came up
Thanks everyone :thumbsup: