- Joined
- Oct 31, 1996
- Posts
- 772
- Type aircraft owned
- Carbon Cub FX-3
- Base airport
- KFCI
- Ratings
- COMM, IFR, MEL, SEL
Everything has been solid for the first year with my CubCrafters FX-3. In early October things started to happen starting with an error message in the G3X "PFD configuration module error" and my Aithre Shield EX 2.0 going haywire and later freezing up. I emailed CubCrafters support as well as Garmin's g3xpert and learned this configuration module is a small chip within the connector itself that plugs into the back of the GDU-465 (G3X display). I was advised to reseat this connector but also advised to open the connector and inspect the module which has a small plugin type connector with small wires. All checked good and after re-seating it all seemed to be fine again.
While doing this I saw where CubCrafters attached power for my forward looking taxi camera piggy backing it on my GMC breaker at bottom right of GDU area. The problem with this is that it's on the avionics bus so I can't view out the forward camera until AV is on which is after engine start. While minimal risk and gain having the option to see the prop area prior to engine start could give that one final check for clearance of 2 and 4 legged critters. So I took the opportunity with the GDU out to move this power wire over to where it was on my prior FX-3 on my taxi light breaker which is lower left of the GDU and this breaker is on the main bus so I can use the camera prior to engine start. Long story short, I thought this may be the cause of my next problem I'll detail but in the end it is not, and right now as I type it's back the way it was from the factory as I've been troubleshooting issues.
So after fixing the PFD configuration module error and replacing a failed Aithre Shield graciously warranty replaced by Aithre I started getting erratic RPM at wide open throttle (WOT) during takeoff. I'd see my usual 2690'ish and then erratic jumps into the red going to the mid 2700's. Very fast movements and the engine was smooth so obviously a gauge issue.
I figured I'd try what CubCrafters wants us to do, despite my disagreement with Facebook being the support channel and I posted to their "OFFICIAL" group on Facebook about my erratic RPM. While no one from CubCrafters participated the peer support was great with a lot of great ideas from a coil pack problem to the need for shielded wire on the two tach wires going from the lightspeeds to the GEA24. I had the GEA24 connector (P243?) disconnected when inspecting wiring for the Aithre issue so I was concerned I may have done something there. I also inspected the lightspeed modules in the right forward panel area. All checked fine. CubCrafters uses unshielded wires for the tach cables and they run right up a main bundle of wires including power sources under the lower right of the panel so very possible there is an interference issue. CubCrafters did ask one of the participants of this discussion about what plane he had as they have this issue with multiple other aircraft supposedly and they are trying to figure out why.
So I decided to undo anything I touched and this past Saturday went to fly and when doing the runup and going to R ignition I had a major drop in RPM and the engine running rough. I also had a backfire on start for the first time, minor, but got my attention and was the first indication of a problem. I also noticed something odd with EGT's that right after startup cylinders 3 and 4 rose to 1000 rapidly leaving 1 and 2 behind around 800'ish. I shutdown in the run up area wanting to see if an electrical cycle would change anything, it did not. I taxi'd back and pulled the SD card from the G3X and went home and posted another post to the "OFFICIAL" Facebook product support group asking for help. The message I posted Saturday evening, still not approved as of this writing is quoted below for anyone that cares to read it detailing my question and request for help.
I reached out for continued help from "Andy" from the CubCrafters forums that graciously gave me much of his time analyzing SD card data, plotting graphs looking at EGT's, etc. I googled and found some good information and others with similar issues and saw about 4 areas it could be from the RPM mini sensors on the flywheel to coil packs, ignition modules, and spark plug or cable issue. The easiest path right now would be to swap the coil packs that are on the bottom which are on the right ignition module, left controlling cylinders 1 and 2, right controlling 3 and 4.
So I de-cowled and took pictures to document before I destructed and it was not easy but good to learn how to remove the coil packs, mainly getting tools in the tight areas. I swapped them and the problem remained as expected but the EGT concern followed over to the 1/2 cylinders and 3/4 were fine. Good sign we have a coil pack issue.
I inspected the mini sensors at the fly-wheel which should have a gap between 0.03 and 0.06. Not easy to get to should you need to work on these things but left side gap was 0.04 and right side is borderline 0.06, may be slightly out of tolerance but has not been an issue to date. If a coil pack change doesn't fix the issue that will be the next to attack.
Coil packs are on order, a replacement and spares so by the end of the week I hope to have a follow-up to share and hopefully with good news.
As to the original Facebook post, I did get an email from Pete at CubCrafters asking for information which was nice. As always Pete is outstanding to work with and responds timely so that is appreciated.
Here is the post I made on Saturday evening asking for help, again at this is still pending moderation.
While doing this I saw where CubCrafters attached power for my forward looking taxi camera piggy backing it on my GMC breaker at bottom right of GDU area. The problem with this is that it's on the avionics bus so I can't view out the forward camera until AV is on which is after engine start. While minimal risk and gain having the option to see the prop area prior to engine start could give that one final check for clearance of 2 and 4 legged critters. So I took the opportunity with the GDU out to move this power wire over to where it was on my prior FX-3 on my taxi light breaker which is lower left of the GDU and this breaker is on the main bus so I can use the camera prior to engine start. Long story short, I thought this may be the cause of my next problem I'll detail but in the end it is not, and right now as I type it's back the way it was from the factory as I've been troubleshooting issues.
So after fixing the PFD configuration module error and replacing a failed Aithre Shield graciously warranty replaced by Aithre I started getting erratic RPM at wide open throttle (WOT) during takeoff. I'd see my usual 2690'ish and then erratic jumps into the red going to the mid 2700's. Very fast movements and the engine was smooth so obviously a gauge issue.
I figured I'd try what CubCrafters wants us to do, despite my disagreement with Facebook being the support channel and I posted to their "OFFICIAL" group on Facebook about my erratic RPM. While no one from CubCrafters participated the peer support was great with a lot of great ideas from a coil pack problem to the need for shielded wire on the two tach wires going from the lightspeeds to the GEA24. I had the GEA24 connector (P243?) disconnected when inspecting wiring for the Aithre issue so I was concerned I may have done something there. I also inspected the lightspeed modules in the right forward panel area. All checked fine. CubCrafters uses unshielded wires for the tach cables and they run right up a main bundle of wires including power sources under the lower right of the panel so very possible there is an interference issue. CubCrafters did ask one of the participants of this discussion about what plane he had as they have this issue with multiple other aircraft supposedly and they are trying to figure out why.
So I decided to undo anything I touched and this past Saturday went to fly and when doing the runup and going to R ignition I had a major drop in RPM and the engine running rough. I also had a backfire on start for the first time, minor, but got my attention and was the first indication of a problem. I also noticed something odd with EGT's that right after startup cylinders 3 and 4 rose to 1000 rapidly leaving 1 and 2 behind around 800'ish. I shutdown in the run up area wanting to see if an electrical cycle would change anything, it did not. I taxi'd back and pulled the SD card from the G3X and went home and posted another post to the "OFFICIAL" Facebook product support group asking for help. The message I posted Saturday evening, still not approved as of this writing is quoted below for anyone that cares to read it detailing my question and request for help.
I reached out for continued help from "Andy" from the CubCrafters forums that graciously gave me much of his time analyzing SD card data, plotting graphs looking at EGT's, etc. I googled and found some good information and others with similar issues and saw about 4 areas it could be from the RPM mini sensors on the flywheel to coil packs, ignition modules, and spark plug or cable issue. The easiest path right now would be to swap the coil packs that are on the bottom which are on the right ignition module, left controlling cylinders 1 and 2, right controlling 3 and 4.
So I de-cowled and took pictures to document before I destructed and it was not easy but good to learn how to remove the coil packs, mainly getting tools in the tight areas. I swapped them and the problem remained as expected but the EGT concern followed over to the 1/2 cylinders and 3/4 were fine. Good sign we have a coil pack issue.
I inspected the mini sensors at the fly-wheel which should have a gap between 0.03 and 0.06. Not easy to get to should you need to work on these things but left side gap was 0.04 and right side is borderline 0.06, may be slightly out of tolerance but has not been an issue to date. If a coil pack change doesn't fix the issue that will be the next to attack.
Coil packs are on order, a replacement and spares so by the end of the week I hope to have a follow-up to share and hopefully with good news.
As to the original Facebook post, I did get an email from Pete at CubCrafters asking for information which was nice. As always Pete is outstanding to work with and responds timely so that is appreciated.
Here is the post I made on Saturday evening asking for help, again at this is still pending moderation.
