Resolved CubCrafters Lycoming cc363i erratic RPM and now running rough on R lightspeed ignition

[Cubonaut875]

It sure has been nice but he's thinking of retiring!

 

[Neal]

Coil pack replaced and engine roughness is fixed. Erratic RPM remains but it seems it's only on the LEFT side now.

I called Klaus at Lightspeed and asked if I should change any other coil packs, he said no, it's not an ignition issue, it's a wiring issue. He said CubCrafters is not wiring the ignition to the GEA24 per the Lightspeed manual and that's the problem. I'm waiting to hear back from CubCrafters but why haven't I seen this issue until a month ago? Strange.

Tomorrow I'll return to the plane and disconnect/reconnect all spark plug leads and disconnect and inspect the spade connectors on the upper coils which are the left side ignition.

Concerning, exhausting, but a good education nonetheless.

 

[Cubonaut875]

Does the erratic RPM present as an alert on the G3X/GDU465? or did you notice it by intrument scan? I keep the same four cameras on pretty much every flight and save the videos to a very large hard drive. I've been looking through my videos to see if I missed and RPM changes. The You Tube videos are pretty much just a fun side rather than the real purpose of the camera's

I definite agree about the education aspect and the extreme admiration I have for homebuilders/ EX3 builders in general

 

[Neal]

Does the erratic RPM present as an alert on the G3X/GDU465?

That's a good point. The RPM goes into a red box so it's easy to see, however, there is no audible alert. But in the past when my prop went to 2710 as the stop is slightly off and/or when I push on the prop lever during takeoff, I do get a "prop overspeed" audible alert. Interesting that I have not gotten that unless it has to be over a RPM for an amount of time and this erratic behavior is not holding long enough.

 

[Neal]

All spark plugs changed today, one more coil pack changed for L ign 1/2 cylinders, still have the issue. Will change coil pack for L ign 3/4 tomorrow putting what came off of L 1/2 as it wasn't bad. I will definitely be changing plugs every condition inspection.

By the way, as you may or may not know, the guidance on changing spark plug wires is at 500 hours. Now I understand why, if you have a bad one it could kill your coils.

Not having fun!

 

[Neal]

Well, it's been a joyous week of a lot of labor that if I couldn't have done this myself probably would have cost me a fortune. One heck of a learning experience and good stuff to learn so all good in the end.

So I had TWO BAD COIL PACKS. Prior to today 3 of them were changed and I still had erratic RPM on the L ignition so I decided to change out the 4th one, so all of them got either a swap or new. All 3 of my new coil packs are in use, I figured why deal with moving what is probably a good existing one over when I have new so I used the new ones. After replacing L ignition cylinders 3/4 (upper right coil) voila, my problem is gone! RPM is now stable.

Flight tested good with solid RPM at 2680 at WOT.

In talking with Lightspeed they have had some quality issues with the manufacturer of these coils, sadly, so getting these original ones out makes me feel better, I still have one in play and will leave it unless another problem presents itself.

 

[Neal]

Here is a video on this saga for those interested: