CubCrafters Lycoming IO-360 (cc363i) erratic RPM and now running rough on R lightspeed ignition

[viator092]

@Neal Yup...you make that mistake once.

@Cubonaut875 ......Cost!!!

 

[Cubonaut875]

@Neal Yup...you make that mistake once.

@Cubonaut875 ......Cost!!!

Ha - I was 99.9% sure of that but I just had to check. I replaced my ignition back up battery at my last condition inspection, of course it should be replaced every inspection, from what I understand, and of course was not at my previous inspection at the authorized Cub Crafters repair facility. So I guess I'm even on overall cost of ignition batteries since I paid 100% more for the most recent replacement.

 

[Cactus Charlie]

You may need your transponder firmware updated. It's the one thing we can't do ourselves.

There is no restriction on updating the transponder firmware for experimental aircraft. You download the tool from Garmin, connect the PC to the wired USB connector, and load the firmware.

Transponder update and PC tool is listed with GDU software here -

Garmin: G3X(TM) for Experimental Aircraft Software Update Collection

G3X(TM) for Experimental Aircraft Updates & Downloads

www8.garmin.com

 

[Neal]

Thanks. I may give it a try someday.

 

[Neal]

I'm going to give this a try tonight, I have the 3.61 from the link you provided @Cactus Charlie. Confirm I plug into the USB type B that's like a dongle under the panel? Just want to make sure I'm clear on where to connect the USB to do this.

 

[Cactus Charlie]

Yes, the transponder has a pigtail terminated with a USB type B connector. Mine is under the right side of the panel.

I have not loaded software/firmware to my transponder. I only got as far as downloading, installing on my laptop, and getting familiar with it. The instructions look simple enough but make sure you keep power on the computer and the transponder until the load is complete.

 

[Neal]

I am seeing the same issue on the GNC 355. It seems to appear more often when there is no other traffic anywhere in range (Canada does not have ADS-B ground stations like the US so I get weather, notams, etc. via SirusXM). I wonder if there is a shielding issue on the Ethernet connection that makes it sensitive to electrical noise?


I have the GTX 45R and the firmware update is possible as the windows software to update it via USB (USB connector is under the panel just behind the USB power) is available on the Garmin site. I need to install a Windows VM on my MacBook Pro and see if the USB will connect.

I have not seen the issue with the ADS-B showing the message in yellow (NO ADS-B) or whatever it was since updating the firmware to the transponder and ADS-B. Maybe it fixed this issue. About to replace the coil packs again, but point is they are the same so maybe it wasn't the cause and the firmware was.

 

[Neal]

Follow up on my coil pack saga going on since Nov 2024. As this thread outlines I had erratic RPM and some other issues which were followed up by a rough running engine on the right ignition. 3 of the 4 coil packs were replaced in Nov 2024 and things returned to normal. Then on Memorial day weekend the right ignition had a failed coil pack followed a week later by the other right ignition coil pack. As 2 of the 3 coil packs removed in November ohm tested good I labeled them as likely good and reinstalled them in June after the 2nd R IGN coil pack failure. Sadly the erratic RPM returned and I had no confidence to go anywhere with the plane, they had to be replaced for my confidence to be restored.

My condition inspection is due in AUG so I took this opportunity starting near the end of July to begin the condition inspection process, de-cowl, and replace the two coil packs with new. It's been a few weeks of work for various reasons including accidentally damaging (cosmetically) the cylinder 3 rocker box cover and waiting two weeks for it to come from CubCrafters as they had some issues with paint and badging it with the "CubCrafters" name plate. During this time though I communicated with Klaus that I felt just continually replacing coil packs was not a good idea, at $500 a pair I hate to not make any other changes and just repeat this cycle. My next step was to replace the spark plug wires. I wasn't confident I was getting good connections when connecting to the spark plugs and after reviewing the YouTube video in this thread a few posts up I learned how to create my own spark plug wires.

I bought the MSD crimper, wire, and ends to make my own spark plug wires. Klaus told me that yes they do make them for CubCrafters so I was going to order spark plug wires from him. After trying to make my own I saw it was not a hard process so I told Klaus I was going to proceed to fabricate my own spark plug wires and replace the four spark plug wires on the right ignition side. He concurred. He also advise me to put the radio in squelch off at times and listen as if there is an ignition issue it will reveal with squelch off. Interesting as with these coil pack issues anytime I key the mic I would at times get feedback in the radio which was annoying.

The rocker box cover finally arrived Thursday so I took Friday to install that, engine run to test for leaks and test the new spark plug wires, and reassemble everything to return the plane to service.

Today I finally got to fly and am optimistic that this was the right change to make. Everything ran great, the EGT's were very nicely balanced at LOP within 5 degrees of each other with cylinders 1 and 2 matching and 3 and 4 matching. CHT's also within a small margin of difference so that was good. I had no feedback when transmitting on the radio and with squelch off nothing unusual noted. I only flew about a half hour as I really felt the need to do a post flight inspection after the rocker box cover replacement so I cut the flight short and inspected with no issues found.

During inspection of the removed spark plug cables I did find some concerns although I don't know the relevance of them. The conductor (black core wire) was cut into on at least one, the conductor was split down the middle and the center exposed on another, and overall the quality of the cables were suspect but obviously I'm analyzing through a microscope here as I struggle to resolve this coil pack saga.

My hope is the bottom cowl is not removed again until next AUG and I'm hoping the new spark plug cables and secure connections to the spark plugs are the answer. The new cables for the most part made a "click" connection but some were tight and it is surprising how hard it is to push the connections onto the spark plugs. I did research whether or not to use dielectric grease in the fittings and from what I could tell the answer is NO but you can use it to help slide the boots back on the ends.

Let's see how this works out from here.

By the way, it is recommended to change the spark plug cables every 500 hours. The cost of new cables from CubCrafters is around $400 but I would buy them direct from Light speed (Klaus) but I don't know the cost but probably significantly cheaper. However, the cost of the MSD crimper is $110'ish, the wire which you'll need probably 4 of to make all 8 cables is around $35/each and then one container of the crimps so the moral is, if you make your own it's about the same cost to just buy them from Klaus. But it is nice to learn and be able to make your own should you need to.

 

[Cactus Charlie]

"The new cables for the most part made a "click" connection but some were tight and it is surprising how hard it is to push the connections onto the spark plugs. I did research whether or not to use dielectric grease in the fittings and from what I could tell the answer is NO but you can use it to help slide the boots back on the ends."

I found it far easier to get the cables to click in place with a light smear of silicone grease on the spark plug insulator tip. A steady push and wiggle works better that a misaligned hard push.

Your history of ignition problems is quite concerning. Did you have any ignition issues with the original style coil packs?

 

[Neal]

This is a 2023 FX-3 so it has the new style as did my 2021. Something somewhere is causing this. The question is what. Klaus wanted me to send him the right ignition module but I wasn’t up for getting that out and my hunch is it would test fine. Next logical step is the cables. Mini sensors appear fine but Dave Embry has a write up of a bad solder situation.

I do wiggle the connector on and even pulled the boot to test with a plug. I’d love to put a little dielectric grease in but need to ask Klaus first if I need to take that step. For now they should be on securely. Just wish I had positive clicks on all of them both sides including coil packs.

 

[Neal]

A quick search again verifies yes dielectric grease on the boot but not on the spark plug connection.

 

[Cactus Charlie]

Putting grease on the spark plug to waterproof the boot and allow easier mating has been common practice for years.

You seem to want to apply aerospace standards to auto plugs and spark plug leads. You would perhaps have been happier with magnetos.

 

[Neal]

Nothing to do with aerospace. It seems for automotive plugs grease on the connection is not recommended.

 

[Cactus Charlie]

The light coating of grease is applied between the spark plug insulator and the rubber boot. The grease should not touch the terminal tip.

 

[Neal]

We're on the same page now @Cactus Charlie - great video as the point I was trying to make is not getting it on the metal connection to the plug. Interesting how they claim it can help with arcing which seems to be one of the key ways to blow a coil pack. Next time I have them off, which I hope is not for a year, I may do as they describe with the q-tip and minimal d-grease on the inside of the boot.