Help...trying to add a tach to 94 Impala ss

Got all the wires hooked up and carefully hiding till I got to the part where I need to tap into a wire into the ignition coil. Three wires...pink with black stripe, pink and white. Suppose to go to a neg wire..used the power meter on all three which all had power. Went by the chevrolet dealership with no answers. HAS ANYONE HOOKED UP A TACH TO AN 94 IMPALA?? Thanks!!!

Found my own answer if anyone wants to attempt this.



An alternative to the PCM connection would be to use the negative coil signal. On a '94 or '95 Impala, there are three wires at the coil, two in a grey connector (pink/black and white/black), and one in a black connector (pink). The negative coil connection for a tach is available in two places. One would be the spare unused terminal location in the black connector (this is what I actually used when I originally installed my tach). The other is the white/black wire in the grey connector. The spare terminal in the black connector and the white/black wire are connected together inside the coil, so they represent the same signal, which is the
negative side of the coil.

Note that '96 Impalas use an improved coil with more spark energy and a different connector with only two wires (although there are three terminals in the coil, only two have wires connected to them). In the '96 models the two wires to the coil are pink/black and dark green. The dark green wire is the negative side of the coil, and could be used to run a tach