The pink lead from the tachometer connects to the (+) positive post (terminal) of the coil. The pink lead supplies12-volts to the tachometer when the ignition is turned on.

We're glad you asked. Electronic Ignition Tach: How It Works In a Distributorless Ignition System (DIS), each coil is responsible for firing one or a pair of plugs, so they fire less frequently.

The Retrogauge Mini-Tach is easy to wire. There are three leads: Signal, 12-volts, and Ground. Signal goes to the "-" or distributor side of the ignition coil.

The tach's third wire (usually brown in color) is the one that actually connects to the negative (-) side of the coil; it serves as the tach's trigger or sensing circuit.

The pulses from the pickup coil (wire loop) coming through the hardware interface to D2 of Arduino triggers an interrupt upon falling. The interrupt is linked to a count process which includes a very ...