One more Hood Tach wiring question
 

I think I'm missing something, the car wiring was all chopped up when I bought it and the Tach was working so during restoration I put all new wiring front to rear, using Autowires HEI engine harness (car had an HEI distributor in it) which does not have a tach hook up in it. Tach has 3 wires coming out, one is ground which is good, one is hooked up to the lights on the fuse panel which is good and works and the 3rd goes to the Tach side of the HEI cap. I have 12.5 volts when the key is in the run position going to the tach but the tach dosnt work when cranking or when started.

The new harness uses a pink wire where the TAN wire coming out of the fuss block which Autowire says is the HEI conversion and omits the tan wire which was a resister wire.
Am I missing a splice into a wire or could it be the Tach just took a dump??

Just thinkg out loud here, I dont have a diagram. The TACH wire should not have a steady 12v, if you put a hand held tach on that wire you should read engine rpm (a test light would flicker) Are you sure you are on the TACH terminal?

It has the 12 volts when the key is on, not running. Would the pulsing come when it's running?