Fitech EFI Rpm Noise Solved

The pickup coil (Hall effect, variable reluctor, etc) doesn't necessarily need to be shielded but the wiring is a must because wiring acts as an antenna

There is also a strategy with BALANCED circuits. Old copper phone lines, and the old TV twinlead are examples of this. Because the wiring is (supposed to be) balanced, it picks up noise equally in both conductors, and this actually causes a cancelling effect.

If you remember TV twinlead, you twisted it....this was to help maintain balance and aid in cancelling noise. Even old telegraph/ telco wires were twisted to maintain balance, AND IN FACT THAT is how ethernet cable works--------CAT-5..

Here is a twist in a telegraph/ telco line. It is for one reason........to maintain balance and to cancel noise

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It is recommended to twist wiring such as the Mopar ECU pickup. This actually may not be as effective in this case, because one leg of the pickup circuit is actually grounded in the ECU. Nevertheless it helps form a shield. This low current "signal" wiring should not only be run away from powerful circuits, especially ignition, but near a "ground plane" that is the firewall