olha bem o manual:
O módulo MSD é capacitivo.
Trigger Wires:There are two circuits that can be used to trigger the MSD Ignition; a Points circuit (White wire) and a Magnetic Pickup circuit (Violet and Green wires). The two circuits will never be used together.
White: This wire is used to connect to the points, electronic ignition amplifier output or to the Yellow wire of an MSD Timing Accessory. When this wire is used, the Magnetic Pickup connector is not used.
Violet and Green(Magnetic Pickup Connector):These wires are routed together in one harness to form the Magnetic Pickup connector. The connector plugs directly into an MSD Distributor or Crank Trigger. It will also connect to factory magnetic pickups or other aftermarket pickups. The Violet wire is positive (+) and the Green is negative (-). When these wires are used, the White wire is not.