Tacho wiring for 20V

[jondee86]

Quote:Then take a wire (splice it to the existing) from the coil negative and
connect it to the tacho wire.

Tacho needs the flyback voltage spike generated by the coil. The wire in
the pic would normally be connected to the OEM igniter, and would get the
signal from there. Since I don't know what ignition system you are using,
I just assumed you would be using the ST coil, which has a plug instead
of open terminals. Therefore I suggested splicing to the negative wire, as
that is where the spike originates.

If you have multiple coils, MSD or some other fancy ignition, it can get
a bit more complicated. Signal converters or pull-up coils are only
required if you are trying to use a low-level tacho signal from the ECU.

Cheers... jondee86