Magneto P lead wiring

[skyyking]

1. Which end do I ground on the magneto "P" lead wire?

2. If I have an impulse coupling on the LH mag only, how do I wire it to the ignition switch, does some provision need to be made to ground out the RH mag during starting?

3. Is it O.K. to bundle the magneto wires thru the firewall with everything else, EGT, CHT, Alternator out, Alternator Field, Master/Battery solenoid switch control, wiring. What I am after here, is there any undesireable noise on these lines that might create havoc, esp to the mags.

Thank you for your help!

[dlloyd3]

Ground the P lead shields at the magneto end only. My Slick 4370 and 4373 mags are marked GRD at the appropriate place.
If using the ACS key start switch from Vans, they have a wiring diagram and provision for grounding the right magneto while starting. Regardless of what type switch or switches you use, you will need to ground the right (non-impulse) magneto while starting.
Keep the P leads away from everything else. I had mine come through the firewall with the alternator then tie wrapped to the main harness under the panel. Had noise while transmitting on the radio. Most of the noise went away when I separated the P leads from the main harness.