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

[Cubonaut875]

I would assume these coil packs are used for certified airplanes as well. Are the specs the same for experimental coil packs equivalent to those used for certified planes? Maybe that is a question for Klaus.

 

[Neal]

I’m happy to report Klaus is going to warranty replace this one. He again reiterates how critical it is that spark plug wires are seated properly and securely as I’m sure mine are after November.

 

[Neal]

Well, something is going on somewhere and I don't know what. Today was supposed to be another long day of flying but I was tired so I chose to just go enjoy the evening after dinner. Runup was perfect and off I went. On takeoff again like last weekend I noticed a sound or feel that wasn't quite right, I checked the RPM and it was fine. I go to lean assist and I already see 3/4 EGT's are running up (last week was 1/2) and yep, leaning is going to run this through 1500 so I turn around and land. I do a runup when clear and again R ignition is rough. So now it's the right ignition opposite pair from last time. Just like last November, dual coil pack failure on the right side.

I have emails out to Lightspeed, now to email CubCrafters. I wonder if I have a bad set of spark plugs? Ignition module? No clue as to what's causing this. It's been perfect for 25 hours since the last time this was changed. Is it a bad batch of coil packs? Plugs were changed in November out of an abundance of caution even though I just replaced them at the condition inspection in July/August.

 

[Neal]

Klaus emailed me back this morning after a few follow-ups I provided such as how it's odd that both R ign coil packs failed each time, near simultaneously. He agreed and suggested I send in the ignition module. It would take a day to inspect it. Well, that's all well and good except that getting the ignition module out is another story and I tried and it's not happening. I replaced the failed coil pack and did a ground run and it checks good. If this happens a third time then I may replace spark plug cables or something along that line. Still waiting to hear Pete's suggestions from CubCrafters support.

 

[Neal]

Klaus called me yesterday afternoon to discuss spark plugs. I had read on the CubCrafters forums the possibility of chinese knock off spark plugs on the market and apparently there was an issue with Denso some time ago. I told him the plugs I've been using were from Amazon and that raises some concern. Apparently you need to be very careful where you buy spark plugs. I told him I ordered 24 directly from Denso as I wanted to ensure this was not a cause of my problem. Apparently you can't get them from Denso, I was slightly misunderstanding who I was buying them from but where I ordered he said is one of the correct suppliers, which I'll link below. They're using a separate domain name but ultimately it's coming from sparkplugs.com which is a reputable distributor.

I changed my plugs out at my condition inspection in July/August, and as they are only around $10/plug from Amazon I changed them again in November during my dual coil pack failure. As I ordered 24 from the link below it was a little over $8/plug. They should be arriving today and then I'll pull all the plugs, resistance check what comes out of the engine and also borescope the engine while I'm decowled as I just bought a borescope not long ago.

Klaus mentioned the plugs should have a resistance of 4-6 kohm so I'll test the plugs coming out and the ones going in. He also asked me about the gap and I told him they measure .031 out of the box and I didn't want to risk breaking the electrode to get them to the recommended .032 as I felt .031 was fine and that they open up over time with usage. He agreed, .031 is fine, if you have too much gap that can cause coil pack problems. He mentioned Bosch makes a good gap tool if needed, I'll just gently use my blade tool to verify 0.031/0.032.

We then discussed spark plug cables and he said pull them straight off, don't rock them side to side. If you get the prongs opened up that can cause arcing and coil pack failures. While I'm confident mine are/were secure, I will inspect them and try to use pliers to see if I can close up the prongs a little to ensure a secure fit when re-attached.

I heard from Pete as well from CubCrafters, he mentioned a few things regarding spark plug wires as well but ultimately he's awaiting feedback from anything I learn. If this happens again I will have no choice but to pull the ignition module and send it to Klaus. I'm hoping it doesn't come to that. As most of the builders know those go in nearly first thing after the fuselage is assembled and it's not the joyous task but it's doable, I just don't want to risk that right now.

Here's the link to one of the reputable sources for the Denso IK27 plugs which I have coming today. Again, I'll be resistance checking between the electrode and opposite end to ensure 4-6 kohm to quality check the plugs prior to install.

Denso 5312 IK27 Iridium Power Spark Plug

Denso 5312 IK27 Iridium Spark Plug - Same Day Shipping. Free Returns. PayPal Accepted. Secure Online Ordering. Est. 1969.

www.densoproducts.com

 

[Cubonaut875]

Great info, I got my spark plugs directly from Cubcrafters, they were$13.36 a plug, so they are more expensive from Cubcrafters.

 

[Neal]

New plugs (24) came today so off to the airplane to swap the plugs, inspect the plug connections, etc. I pulled the 8 plugs and they looked fine as expected for 25 hours of use. I inspected the plugs for anything that looked like a foreign country knock-off, nothing noted. I inspected the 3 boxes (4 plugs per box) and nothing odd there. I feel safe that the plugs from Amazon are okay, however, here's my opinion and lesson learned. We're lucky we get to use automotive plugs, but in an airplane we need to pay attention to approved vendors for our parts. I bet if anyone asked Denso if Amazon is an authorized reseller they would answer a loud NO. This happened to me once before buying a pioneer dash radio which failed and I learned it wasn't an authorized seller so warranty void.

Back to the plane...pulled the 8 plugs and resistance checked them. Nothing abnormal noted, they met the criteria Klaus mentioned of 4-6 kohm's. I pulled 8 plugs from my new supply and did a quick gap check to ensure they are .032 or less and they did, all the same out of the box at I'm guessing .0315, i.e. very close to the .032 but I don't like to touch the fragile tip of the electrode so it was a gentle check. I then resistance checked the plugs prior to install and 6 of them tested at 5.7 kohm's and 1 was 4.9 and the other 6.3. If six were consistent why were the two not? So I set those aside and pulled two more and they were 5.7. I'm not settling for anything here, all same resistance plugs installed and torqued.

Then the cables. I chatted with Klaus about using pliers to compress the clips to ensure a good fit and he said yes. One of the 8 came off easier than the others which got my attention, it was on the R ignition circuit. So I used pliers and gently compressed the clips, well, that made it impossible to install about 3 of them so that took some work but they are very secure and I also paid attention to how far down the plug the orange silicone sleeve goes to ensure the depth looks correct. Yeah, who'da'thunk so much effort needs to be involved in plugs! But any arcing apparently can kill a coil pack, so learn from this when you inspect or change plugs, and don't rock the wires side to side, pull them straight off.

While all 8 plugs were out I used my new borescope tool to take a look. Scary stuff, not smart on what I'm seeing but definitely some buildup on the pistons. Valves looked good to me. I'll post some pictures at another time in my borescope thread.

Tomorrow or later will be a test run and then the joy of reassembly, again. Hope this saga is behind me but I'm carrying all spare coil packs I have left (2).

 

[Neal]

Figured I'd do some research to learn more about Light speed ignitions and coil pack issues. Came across this video which is quite educational on spark plug wires. I didn't realize the end boots could come off. Would have been better if I did that to adjust crimp strength on the plug. I have one I'm concerned about so I may pull it and check it.

 

[viator092]

Very very sad. You better be carrying a spare coil pack. Today again was a day this would have found me 1.5 hours away from home just like the last time, in almost the same location I flew 6 months ago when this happened on the way home.

Did you get your spare coil pack from LightSpeed? Made the mistake buying the backup ignition battery from CC. Never again.

 

[Neal]

Did you get your spare coil pack from LightSpeed? Made the mistake buying the backup ignition battery from CC. Never again.

Yes. And in the YouTube video I watched yesterday he tipped off that Klaus (Light speed) makes the spark plug wires. We are supposed to change them every 500 hours. I'll email Klaus to see if he makes them for my plane and if so how much as I have a feeling it will be significantly cheaper than the $486 on the CubCrafters store. Okay, I deleted what I was going to post and leave this where it is. Be smart with your shopping both when buying the plane as well as components after. Nuff said

 

[Neal]

Great info, I got my spark plugs directly from Cubcrafters, they were$13.36 a plug, so they are more expensive from Cubcrafters.

The problem here is you don't know where they got them from. They could have ordered from Amazon in bulk as well. Consider buying from an authorized distributor in the future just to be safe but I learned a bigger lesson of resistance testing new plugs before they go in your plane.

 

[Neal]

Yes. And in the YouTube video I watched yesterday he tipped off that Klaus (Light speed) makes the spark plug wires. We are supposed to change them every 500 hours. I'll email Klaus to see if he makes them for my plane and if so how much as I have a feeling it will be significantly cheaper than the $486 on the CubCrafters store.

I emailed Klaus to see if he makes them and the cost. I also added the parts required to make them myself to my Amazon cart, all MSD branded wire, 90 degree crimps, crimp tool, and doing it yourself would cost the same or more than just buying them pre-made. As it's not something we change often I don't see going down the DIY path but if my coil pack issue continues and my next step is replace some of the spark plug wires then it may be something I pursue to replace some, not all, of the wires, i.e. right ignition side only.

 

[Neal]

Did you get your spare coil pack from LightSpeed? Made the mistake buying the backup ignition battery from CC. Never again.

Wow!!! CubCrafters wants $91 for the PS-1221S battery?

Here is where I got mine in the past:

https://us.rs-online.com/product/power-sonic/ps-1221s/70115556/

https://www.batteryjunction.com/powersonic-ps-1221s-f1

Around $30 from the above. My condition inspection is approaching so time to order one. Will evaluate shipping cost from each and order now.

Bought from battery junction - $39 shipped.

I saw CC's EarthX pricing, seems about $200 more than buying direct from EarthX. Shop smart!!!

 

[Neal]

Klaus emailed me back today (Sunday) and told me that yes, they are the one's that make the spark plug wires for CubCrafters. So when the time comes you need any or all spark plug wires, reach out to Light speed directly.

 

[Cubonaut875]

Did you get your spare coil pack from LightSpeed? Made the mistake buying the backup ignition battery from CC. Never again.

Did you regret due to cost or quality?

 

[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.