P-lead routed with LSE Sensor?

[szicree]

I know Klauss is pretty particular about what gets routed with the sensor wire, but is the P-lead okay? I'm running it to my EIS, so I assume something is flowing through it, but is it enough to disturb the LSE?

[elippse]

If you are referring to the P-lead from the magneto, it is connected to the primary of the ignition coil in the magneto. As such, it can see fast rise pulses of at least 100V peak, depending on the cylinder's charge density. That could lead to much signal cross-coupling. If you connect the ignition switch ground terminal to the airframe, you have now created an extra antenna lead to the P-lead to radiate pulsing noises into the radio. The P-lead shield should be tied to the magneto case and the ignition switch only, with no other ground leads connected to it. When the ignition switch is open, ignition hot, the P-lead and its shield effectively form a capacitor in parallel with the magneto's capacitor (condenser) and the points.

[szicree]

I appreciate the info. What you're describing is what I've got, shielded wire attached to the mag and to the switch. The ground is connected only to the switch and the mag ground, but when the switch is on I'm sending the signal from the p-lead to my EIS tach input (after routing it through a resistor). It sounds like the juice running through this wire will confuse my LSE so I guess I'll route it well away from it.