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Ignition noise in the radios?

airguy

airguy

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I've got one mag and one Lightspeed Plasma, and the Plasma is putting out significant radio-frequency interference that breaks the receiver squelch on my radios. I'm running auto plugs in the Plasma side, is this likely a plug problem or something else? Where do I start with the troubleshooting?

I have most definitely narrowed it down to the Plasma EI, first off. The noise I hear in the radio is a ticking that is RPM dependent, just exactly like I would expect from hearing the spark plugs fire.
 
aerhed said:
Did you try it with the alternator off? EZ stuff first.
Click to expand...

Actually, yeah - I did, though I suspected all along it was the ignition. I can isolate it via the ignition switch to the right side (Plasma EI) and pulling the breaker on the Plasma power causes it to come and go. It's definitely coming from the EI.
 
Plugs/Wires

I had a noise issue once, it was due to a loose plug wire to sparkplug connection.

Just a thought.
 
N941WR said:
What ignition wires and sparkplug are you running?
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Automotive-style wires and plugs - came with the engine (plugs were new or at least appeared new) thus they are suspect. Doesn't this application need resistor plugs for exactly this reason?
 
Do the plugs have spin on caps like lawnmower plugs?

The wires could be breaking down.

If "old" wires and plugs, replace them all, they don't cost much.
 
Thou speakest truth.

The wires are widely available, any suggestion for a resistor-type plug?
 
I run NGK BR8ES, gapped to .032. Search the forum for the part number as they sell rwo versions; one with screw off caps and one without.

Please report back with your results.
 
Wires and/plugs

I've run many Lightspeed systems and never had ignition noise. I gapped the plugs at .027 and used the BR8ES, BR8EIS, and IK27's. The wires are supposed to be replaced every 5 years. I replaced mine every 2-3 years or at 500 hours. The wires do break down. Use good 8mm MSD wires. They are easy to make yourself. Bad wires and plugs can stress the coils. I have seen coil failures on the Lightspeed and replace them every 5 years as well.

One of the the things I noticed is the the MSD wires that Klaus provides have about 50 ohms per foot. The Taylor wires provided by Electroair have about 350 ohms per foot.

Vic
 
If your problem isn't related to non-resistor wires/plugs - those will definitely generate a lot of noise - try cleaning and then coating the insides of the sparkplug boots with a light film of dialectric grease.

When I first flew the Rocket I hadn't done this and the ignition noise slowly built up over a period of time, ~20 hours maybe, until it was so loud it was making it impossible to hear anything but stations that were very close. The noise went completely away once I cleaned and greased the plug caps, and hasn't come back since.
 
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Plugs are cheap, they'll get replaced. The high voltage wires are well outside their 5-year lifetime, I'll replace them also, that's easy enough. I sent an email to Klaus late last night and he already responded that I should ONLY use the MSD 8mm wire because it's 50 ohms per foot, and has its own internal RFI shielding.

Thanks for the suggestions.
 
If you're using plugs with the threaded terminal on top, make sure the terminals are tight in the short term. Switch to solid terminals in the long term.
 
I had radio squelch breaking on mine - the problem was a little corrosion on the metal parts inside the boots which clip on the spark plugs. I removed the corrosion with a piece of Scotchbrite, and sprayed a little Tri-Flow in them prior to re-assembly. Problem fixed. I now put Tri-Flow in them each time they come off. My wires are about 8 years old, about 800 hours. Dual Plasma III's.

Interesting side note: the corrosion was just such that turbulence would create the squelch breaking. I could pull 2 g's, break squelch, relax, ok. Must have been a subtle movement of the boot.
 
airguy, curious, did replacing the ignition wires fix your problem?

I have dual plasma iii, and LSE1 creates a lot of interference (it's gone when I switch LSE1 off). I have reseated all the cables, the plugs are new (50 hours or so) so I am at a loss where else to look for the interference.
 
rotoiti said:
airguy, curious, did replacing the ignition wires fix your problem?

I have dual plasma iii, and LSE1 creates a lot of interference (it's gone when I switch LSE1 off). I have reseated all the cables, the plugs are new (50 hours or so) so I am at a loss where else to look for the interference.
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Check the fast-on connectors on the coils.
 
rotoiti said:
airguy, curious, did replacing the ignition wires fix your problem?

I have dual plasma iii, and LSE1 creates a lot of interference (it's gone when I switch LSE1 off). I have reseated all the cables, the plugs are new (50 hours or so) so I am at a loss where else to look for the interference.
Click to expand...

Is this a new problem or has it always been there? If new, replace the coax going to the coils. If still there, swap the coils between the two Lightspeed ignitions and try again. If the problem moves you found the bad coil.

I assume you already tried replacing plug leads.

Carl
 
AlexPeterson said:
I had radio squelch breaking on mine - the problem was a little corrosion on the metal parts inside the boots which clip on the spark plugs. I removed the corrosion with a piece of Scotchbrite, and sprayed a little Tri-Flow in them prior to re-assembly. Problem fixed. I now put Tri-Flow in them each time they come off. My wires are about 8 years old, about 800 hours. Dual Plasma III's.

Interesting side note: the corrosion was just such that turbulence would create the squelch breaking. I could pull 2 g's, break squelch, relax, ok. Must have been a subtle movement of the boot.
Click to expand...

Just out of curiosity, wouldn't the Tri-flow act as a insulator a bit? Or do you put it on the boot portion only?
 
rotoiti said:
airguy, curious, did replacing the ignition wires fix your problem?
Click to expand...

Actually yes - I made a new set of wires with MSD material and the problem disappeared immediately. I must have had a case of old or damaged wires somewhere on the engine.
 
Carl, the problem is new, appeared maybe 15-20 hobbs hours ago.

I have not yet tried replacing the plug wires, no. They only have 240 hours since new. Should I look into that?

I can swap the wires between LSE1 and LSE2, that's a great idea.
 
I had radio noise from the ignition on the Plasma III and found that closing the plug gap down to .030" eliminated the radio noise. When the plug gap increases to the mid .030's, the radio noise returns. Reducing the plug gap made a major reduction but changing plugs to a different brand made very little difference.
 
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