I bought an RV-10 a bit over 2 years ago with dual LSE ignitions. While trying to chase down a different issue about an oil-fouled spark plug (which I posted on a different thread), I ran a GAMI lean sweep followed by an inflight LOP ignition test and then I repeated it - this was on Aug 3rd.
In the attached chart (which starts at the end of the first GAMI sweep), you can see the ignition test starting at about 00:37:20. After that ignition test, you can see (starting at about 38:30), the EGTs on #2, #4 and #6 climbed above 1400 and stayed there until I started to enrich the mixture. When I leaned the mixture again, they went back up and when I did the ignition test again, when running on just the left ignition, the engine essentially died ((at about 46:30). It looks for the 2 seconds that we were on just the left ignition, the EGTs on #1 and #2 plummeted. The behavior did not change even after enriching the mixture. Also, after landing, I was able to reproduce it (engine running very badly on just the left ignition) even at idle RPM.
The evidence seemed to point to the coil on the left ignition that supplied #1 and #2 cylinders. I worked with my A&P to figure out the coil to plug to ignition mapping and figured out what appeared to be the problem coil. I happened to have a spare coil which came when I bought the plane so I went ahead and replaced the problem coil (let's call it L1 since it was the first coil on the left ignition).
I did a test flight on 8/10 and I wasn't able to reproduce the problem so I thought I had fixed it.
Then, on a flight with 2 passengers last Sunday (8/18), as I was leaning the mixture for cruise (with both ignitions on), I noticed that the some of the EGTs had increased above 1400 and were not coming down (they started going up even when I was quite a bit ROP). I decided to do a precautionary landing enroute at Byron (C83) and when I did an ignition test on the ground (at about 54:40 in the 2nd image), I had the same issue where the engine ran very badly on just the left ignition and looking at the chart, it again shows the EGTs on #1 and #2 plummeted when the right ignition was turned off. I repeated it at 55:24.
I went ahead and replaced the L1 ignition coil with the one that was in the plane originally and when I started the engine and did an ignition test, the same issue kept happening. It was a hot day and I had some suspicion that it may be heat related so at that point, I parked the plane in a maintenance hangar and went out for lunch with a helpful local pilot. When I started the engine around 1-1.5 hours later, the problem did not show up on the ground during a high RPM run-up so I headed back to home base (KRHV - about a 20 min flight) and had an uneventful flight.
I have been exchanging emails with Klaus and also spoke with him. Given my (low level of) knowledge and his expectations, it has been a bit challenging!
A few questions:
- Could this sequence of events (the EGT behavior and the badly running engine on one ignition) point to any other possible issue (other than the ignition)? I have separately been chasing a different issue where it looks like my A&P's uninformed lackey took the Airflow Performance restrictors out to be cleaned at the time of the CI in March and then put them back in randomly. So, I have been going through the GAMI sweeps and changing the restrictor locations to get a better spread.
-Any suggestions on what may cause this kind of intermittent ignition issue (which may possibly be related to heat)?
-Am I possibly chasing more than one ignition related issue?
Here are my next planned steps:
-I worked with my A&P to figure out the ignition coil to spark plug mapping but I am now not 100% sure we got it right so we are going to repeat that tomorrow using a induction timing gun (to know exactly which plugs/coils are on which ignition circuit).
-If it turns out that I previously got that wrong, then perhaps I have replaced the wrong coil in the past so I will replace the appropriate coil (which fires #1 & #2 on the left ignition)
-if it turns out that the previous mapping I had was correct (and I was dealing with the correct coil), my plan is to swap that coil with the next coil over (which is a known good coil/channel on #3 & #4) to see if the problem moves to #3/#4 or if it stays with #1 and #2 in which case it may point to the channel on the LSE Plasma controller being the issue.
One other suggestion I had was to ensure that the spider is distributing fuel ok so I guess I am planning to do the "cup test".
Any other insights or suggestions are welcome!
Thanks,
Vas
In the attached chart (which starts at the end of the first GAMI sweep), you can see the ignition test starting at about 00:37:20. After that ignition test, you can see (starting at about 38:30), the EGTs on #2, #4 and #6 climbed above 1400 and stayed there until I started to enrich the mixture. When I leaned the mixture again, they went back up and when I did the ignition test again, when running on just the left ignition, the engine essentially died ((at about 46:30). It looks for the 2 seconds that we were on just the left ignition, the EGTs on #1 and #2 plummeted. The behavior did not change even after enriching the mixture. Also, after landing, I was able to reproduce it (engine running very badly on just the left ignition) even at idle RPM.
The evidence seemed to point to the coil on the left ignition that supplied #1 and #2 cylinders. I worked with my A&P to figure out the coil to plug to ignition mapping and figured out what appeared to be the problem coil. I happened to have a spare coil which came when I bought the plane so I went ahead and replaced the problem coil (let's call it L1 since it was the first coil on the left ignition).
I did a test flight on 8/10 and I wasn't able to reproduce the problem so I thought I had fixed it.
Then, on a flight with 2 passengers last Sunday (8/18), as I was leaning the mixture for cruise (with both ignitions on), I noticed that the some of the EGTs had increased above 1400 and were not coming down (they started going up even when I was quite a bit ROP). I decided to do a precautionary landing enroute at Byron (C83) and when I did an ignition test on the ground (at about 54:40 in the 2nd image), I had the same issue where the engine ran very badly on just the left ignition and looking at the chart, it again shows the EGTs on #1 and #2 plummeted when the right ignition was turned off. I repeated it at 55:24.
I went ahead and replaced the L1 ignition coil with the one that was in the plane originally and when I started the engine and did an ignition test, the same issue kept happening. It was a hot day and I had some suspicion that it may be heat related so at that point, I parked the plane in a maintenance hangar and went out for lunch with a helpful local pilot. When I started the engine around 1-1.5 hours later, the problem did not show up on the ground during a high RPM run-up so I headed back to home base (KRHV - about a 20 min flight) and had an uneventful flight.
I have been exchanging emails with Klaus and also spoke with him. Given my (low level of) knowledge and his expectations, it has been a bit challenging!
A few questions:
- Could this sequence of events (the EGT behavior and the badly running engine on one ignition) point to any other possible issue (other than the ignition)? I have separately been chasing a different issue where it looks like my A&P's uninformed lackey took the Airflow Performance restrictors out to be cleaned at the time of the CI in March and then put them back in randomly. So, I have been going through the GAMI sweeps and changing the restrictor locations to get a better spread.
-Any suggestions on what may cause this kind of intermittent ignition issue (which may possibly be related to heat)?
-Am I possibly chasing more than one ignition related issue?
Here are my next planned steps:
-I worked with my A&P to figure out the ignition coil to spark plug mapping but I am now not 100% sure we got it right so we are going to repeat that tomorrow using a induction timing gun (to know exactly which plugs/coils are on which ignition circuit).
-If it turns out that I previously got that wrong, then perhaps I have replaced the wrong coil in the past so I will replace the appropriate coil (which fires #1 & #2 on the left ignition)
-if it turns out that the previous mapping I had was correct (and I was dealing with the correct coil), my plan is to swap that coil with the next coil over (which is a known good coil/channel on #3 & #4) to see if the problem moves to #3/#4 or if it stays with #1 and #2 in which case it may point to the channel on the LSE Plasma controller being the issue.
One other suggestion I had was to ensure that the spider is distributing fuel ok so I guess I am planning to do the "cup test".
Any other insights or suggestions are welcome!
Thanks,
Vas