Radio noise

Requesting assistance from all you electron chasers.

Recently I have been getting radio noise in my King 97A. I only get this noise,which sounds exactly like when the squelch is ON, above 1800 RPM. I have dual Plasm III ignition systems installed and have narrowed it down to the right system (goes away when right system switched OFF). I have checked everything I can think of with no positive results. Any thoughts greatly appreciated.

It would be helpful if you provided some more info on your installation. but I'll take a shot. The Plasma III does draw more current as the RPM increases so it's important that the power leads coming from the battery all the way back to the ignition box are shielded. Also keeping the wires that connect to the ignition coils away from avionics as much as possible. Again posting a wiring diagram and what you've already tried would help.

I had a plasma II system and frequent changing of the spark plug leads was necessary to keep radio noise under control. By frequent I mean every 100 hrs became routine.

Klaus tends to like lots of spark energy which overpowers the supression in the wires if it deteriorates at all.

Thanks for your suggestions. I will look at the installation wiring and spark plug leads. I will also look through my records for the wiring diagram.

Same problem

I had the exact same problem even isolated to the right side too on an EFii system. I was told that that sort of ignition noise can only come from either spark plugs or spark wires. To fix the spark plugs the recommendation was to increase the gap. You will need to find out what gap size is tolerable on your system before doing that. I did that and it did not fix my problem. I changed out my spark plug wires and it went away. I have read that in some installations carbon spark plug wires are necessary but they need to be changed out annually. Hope this helps.