Fitech EFI Rpm Noise Solved

Good call on the shielded wiring. Every low amp ac circuit is supposed to be shielded from noise as much as possible. 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 and electrical noise (starter, coil, msd, plug wires, overhead power lines, radio freqs) will alter the ac signal and give you crazy rpm/cam/crank timing readings. Not what we want with a boosted V8.

Megasquirt made it hard for me and I faught it til i finally realized i needed a pull-up resistor in line with the pickup.