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Lightspeed plasma III ignition noise

AltonD

Well Known Member
I saw a thread earlier this year about this very issue. I searched and cannot find it.

My plasma ignition is causing some noise in my 430W. Has anybody else had this problem? if so, how was it resolved?

The output leads are ran seperate. the unit itself is mounted right behind the 430. Avionics filter?
 
Use dialectric grease on all the high voltage boots/connections (coils and plugs). This will last ~ 100 hours, repeat at annual or when the noise comes back. Make sure you carefully clean the insides of the boots and the spark plug insulators before using the grease.

I'm assuming, of course, that the noise you're hearing is ragged ignition noise in your com audio.
 
I'll give it a shot. I did notice yesterday that the noise is most prevalent at low RPM.
 
Hi Alton,
Are you also running with 1 mag on your system? If so, does the EMI noise go away when you power down the EI and just run on the mag? Is the noise a click or more like a chirp or just a ratty, scratchy noise?
Thomas Shpakow
G3i
 
One mag, one EI. It sounds more like a chirp and does go away when I kill the EI. It does vary with engine rpm. At higher RPMs, it almost appears to be gone.
 
One mag, one EI. It sounds more like a chirp and does go away when I kill the EI. It does vary with engine rpm. At higher RPMs, it almost appears to be gone.

Check the posts on your Lightspeed coils. I had one break loose after a zillion hours, but it wasn't a hard failure. First signs were clicking noise, before the EGT even started to indicate anything amiss. (BTW, the only reason the post broke loose was because my spark plug wire retaining clip broke...chain of events...).

Definitely worth a quick look-see (wiggle the posts and make sure they're still epoxied in good as new, and make darn sure your spark plug wires are held by clips), and I second the comment about checking the spark plug connectors & boots & using something like DC-4 in there.

Hopefully it's something simple & easy & cheap.
 
For that matter, double-check the plug wires at the plugs, too.

I've had Lightspeed in two aircraft, never any noise.
 
Thanks everyone. I will try all of these.

Dan, what type of clips are you using to retain the Plasma spark plug wires as the run over to the plugs? BTW, you need one more post to bust 2000.
 
Dan, what type of clips are you using to retain the Plasma spark plug wires as the run over to the plugs?

My Lightspeed kit came with a couple of plastic clips for the wires. I got a couple more. They look like this:

250


I use two per side. If memory serves, on each side I have one secured to a pushrod tube, and the other is just "inline" as a stabilizer sorta dealie. The key imho is to keep those spark plug wires from flopping around at all, and it takes any sort of stress off the coil posts. If the wires be floppin', the coil posts be breakin'.
 
Hello Alton,
Has the chirp noise been there since you installed your LS? If so, with a cap discharge ignition system possible small traces of EMI (most noticeable @ low RPM) could be back feeding to your main busbar, depending on where you connected to your power source. We solve this issue with a 26k uf cap filter.
Thomas Shpakow
G3i
 
[...] with a cap discharge ignition system possible small traces of EMI (most noticeable @ low RPM) could be back feeding to your main busbar, depending on where you connected to your power source. We solve this issue with a 26k uf cap filter.

Hi Thomas,

Could you elaborate on this a bit? I am about to run the power wires to my LSE Plasma III box and I've been thinking about the EMI issue a lot. I assume you put the cap directly across the power/ground inputs as close as possible to the LSE CDI box, correct? I could probably find room for a cap like this one at this stage in my build (it's a 26mF 50V cap - hope that link works).



thanks,
mcb
 
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My power comes right off the battery, then to a breaker on the panel with all of the other breakers. I suspect this is the problem. That puts the power wires running in parallel through the harness.
 
Hi guys,
That is correct; Mount the cap as close as possible to the module and directly across the power/ground inputs. Matt, the one you pick out (p/n DCMC263U050AC2B) from Mouser will work just fine also.
The 26k capacitor that we use on the modular Series-1 ignition kit is available separately through us ($45.00); we purchase these caps from MSD (MSD P/N 8830), or you can pick these up locally @ quality auto parts store or order also through Jegs or Summit racing. The dimensions are (2.500?H x 2.00?W) and it comes with a mounting bracket. The voltage rating on the MSD cap is 35 volts. Here?s a link to our page with the MSD cap info: http://www.g3ignition.com/MSD_installation_instructions.html#
Series-1 install drawing showing the cap filter wired. http://www.g3ignition.com/series-1 drawings cs.pdf
Our Series-2 module has the internal cap (same 26k capacitance).
Hope this helps,
Thomas Shpakow
G3i
 
Thanks, that's very helpful. I think I will make provisions for mounting a cap near my LSE box, just in case I need it. Much easier to install an extra nutplate now instead of later when I'm lying on my back. :)

cheers,
mcb
 
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