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Diagnosing high EGTs - a long sad story

jbell2355

Member
In early October, I signed a purchase agreement on a beautiful RV7A built by a physician here in Michigan. He had his CFI friend fly the plane up to my neck of the woods for a pre-buy inspection. I got the green light from the A&P and sent the wire transfer ? the plane was mine!

The CFI and I hopped into the plane for a few landings and then I flew him back home solo. I recall during that first run-up that the engine seemed to run rough on one mag, but the CFI didn?t seem too concerned and it was my first time in the plane, so I didn?t know what was normal. On my 2 hour return flight home, all alone in a new plane, I started getting a high EGT annunciation on cylinder #4. This was disconcerting for me, having never had this kind of engine monitoring info and being new to the aircraft.

Back home, I consulted with the builder who told me that he hadn?t had this issue before. At first it seemed it had to be related to the pre-buy inspection, but what could the mechanic have done that would cause this? We did a little troubleshooting and decided it was probably a bad EGT probe. I flew the plane regularly and found that the annunciation was mostly an issue on climbout and that with proper leaning (or lack thereof), I could mostly manage the high EGT. Cylinder head temps did not appear out of line.

I flew the plane for 25 hours and brought it back to the pre-buy mechanic for a supervised oil change. I uncowled the plane and was shocked to see that the #4 high tension lead was disconnected from the upper plug on cylinder #4 (Lightspeed Ignition). The only good news was that we now knew the source of the problem. The mechanic was very nonchalant about the fact that he left the plug unplugged, and didn?t seem bothered by it at all. I wasn?t very happy, except for the fact that we thought we had solved the problem.

I flew the plane home after the oil change, excited to finally be rid of that irritating flashing red light, but it was still there! For the next few months, I swapped EGT probes, installed a new one, had them tested, checked for wiring problems, and spent a lot of time messing around trying to diagnose the problem. I was about to send the GRT EIS monitor back to be tested, when I shared some engine monitor info with Doug Hamerton at Aero Sport Power (the engine builder). He felt that, based on the data, I was leaning #4 lean of peak and that?s how/why the temp was going back in line with the other cylinders which were leaned ROP.

At this point I had put 80 hours on the engine. I had the mechanic on my field take a look and he told me I had a leaking exhaust valve, so I had him pull the cylinder. Based on the amount of carbon buildup, we decided to pull all the cylinders and have them looked at by Doug.

https://ibb.co/hAkrGJ
https://ibb.co/dPf2Oy
https://ibb.co/i3zJwJ

Aero Sport did their thing and a few weeks later the cylinders were remounted. 2 new pistons, 1 new #4 cylinder and the rest just cleaned up/painted. Once it was all put back together, I fired her up and did the ground run procedures.

Then I flew it, and still had the **** EGT problem!

This isn't the end of the story, but I?m going to stop the story here for a day or two. You should know that we did subsequently find and fix the problem. I?m curious whether anyone would have saved me all this hassle I've been through if I would have asked sooner.

And Klaus, you?re not allowed to answer.

So...what happened here?
 
Snopercod, yes, it is carbeurated. It's an O-360.

Kahuna, you hit the nail on the head! Where were you $5,000 ago? Neither mechanic I worked with thought of a bad coil. Neither knew that running the ignition without a plug would burn up the coil.

#4 was running rich after the pre-buy inspection. I assume this was because only 1 plug was firing. Eventually, it started running lean - because enough fouling of the exhaust valve caused a leak on the intake stroke. This was puzzling to me at the time, but now it makes perfect sense.

Anyhow, I hope this post saves someone else a few bucks down the road!

So, next question...does the pre-buy mechanic have any liability here?
 
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Coils fail for a number of reasons. High resistance is the usual culprit. The coils can fail one side (one lead) or both side (both leads same coil) and can often be intermittent. The check for it is pretty easy. When you have a high EGT and a suspect coil, do an ignition check. Boom there it is. AND, since you mentioned that the lead was off for some period of time, it certainly would have failed an ignition check at run up.
 
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So, next question...does the pre-buy mechanic have any liability here?

And FWIW, while the mechanic may have failed to put the lead back on, you got in the plane and flew it many times for 25 hours and certainly failed to deal with the ground run ignition check failure. Your systems were telling you there was a problem. During run up, while rough, the engine monitor would have clearly showed the problem, which cylinder, and which ignition. A lead off would have been very rough, enough so that even without an engine monitor, it should have been back to the hangar for diagnosis. Even taking into consideration that you were unfamiliar with that plane, any engine would have shook and should have been an immediate red flag to any pilot.
 
This is a worthwhile thread for everyone on recognizing when the engine is telling you there is a problem.

With any igntion, mag checks are best done by observing EGT change. No matter what igntion you are running, turn off one side and all EGTs should go up. If they don?t, one or more cylinders are not firing properly. Park the plane and find out what is wrong. Do not rely on RPM drop alone.

Lightspeed coils have, in my experinece, failed on high resistance as discussed in previous posts. Yours failed because you had a plug disconnect. I suggest more common mode is a plug lead going bad. You need to verify lead resistance at every inspection.

Verify spark plug resistance in range at each inspection as well when you clean them (aircraft plugs) or replace them (EI auto plugs).

Do not ignore when the engine is talking to you. Believe your instruments until you prove them wrong.

Carl
 
Great advice by Carl and Kahuna.

At EVERY ignition check before EVERY takeoff, look for all EGTs to rise by 20 or 30 degrees when you switch from both to one ignition, as well as a slight drop in RPM. When you switch back to both, look for all EGTs to fall back to where they were and for the RPM to rise slightly to where it was. Do this first on one ignition, then on the other. If ALL EGTs DON'T CHANGE as described, decowl and find out why - because you are operating without the redundancy of dual ignitions at that point - and you are one ignition failure away from a forced landing.

One other suggestion is post on this forum when you have a problem, you will get a lot of good suggestions by very seasoned, knowledgeable, and helpful individuals. :) Would have saved you a few $k in this case - from your description that was an easy diagnosis, even over the internet. :)
 
Great advice by Carl and Kahuna.

At EVERY ignition check before EVERY takeoff, look for all EGTs to rise by 20 or 30 degrees when you switch from both to one ignition, as well as a slight drop in RPM.

This is new info to me. Thank you.

I am flying a 172 now and the only thing I have been taught to look at is RPM drop.

The plane does not have the G3X system I have with the sensors on nearly everyplace on the engine so I guess that is all it has. It is amazing the info we have available now that wasn't even thought of even 10 years ago. The trick is to learn it all.
 
At EVERY ignition check before EVERY takeoff, look for all EGTs to rise by 20 or 30 degrees when you switch from both to one ignition, as well as a slight drop in RPM. When you switch back to both, look for all EGTs to fall back to where they were and for the RPM to rise slightly to where it was.


What Noah said above. Don't just look at RPM on a mag check, watch the EGTs rise.
 
Kahuna pretty well nailed it in post #6.

Engine monitors are great, but seriously, you don't need to watch EGT's to notice the engine is not running right when switching mags.

Don't want to make things worse for the original poster by ragging on him but jeez it sounds like he just totally disregarded a rough running engine and decided to fly anyway, that was a really bad decision that could have made for a really bad day.
 
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Really?

I don?t understand wanting to fault the prebuy inspection. The wire may have come off due to some other anomaly, not necessarily left off by someone. And a cylinder not firing on a 4 cylinder engine when doing an ignition check has a pretty good shake to it. And a totally bad coil as mentioned here will cause 2 cylinders to not fire during the ignition check. That one is kind of hard to miss!

I really don?t understand the decision to fly when one has that kind of problem going on. Ok, maybe once in the first flight home and claim unfamiliarity, but after that it?s hard to justify.

Vic
 
Plug Wire

Thanks for posting I'm sure a lot of readers learned a lot .The OP did a good service less not hit him to hard were other wont post.
Bob
 
LESSONS LEARNED, or NOT?

great discourse here, the post is meant to educate, and it did that.
thank you all.

now;
why?
HOW would 'a pilot' know what an engine with one bad lead/plug/coil sounds like? it sure as heck isn't taught in flight skool!
unless you've flown a few dozen hours with a seasoned pilot ( as noted here) you will not get this kind of knowledge .......without experiencing it ( a failure!)
NOT a good way to learn, perhaps? as they say, 'you'll not live long enough....'

I built engines as a teen, hot-rodded around, my Dad built and flew aircraft since I was a youngster, but still, .........can I diagnose the difference at runup, between carb ice, fouled plug, leaking intake runner, bird nest in the air filter...etc etc.
NOT really! and there are quite a percentage of pilots, especially 'new' ones, that didn't grow up on the farm, or in a hangar, who really need a good education.
.....and I'll be right behind them in class! ;-)
 
I don’t understand wanting to fault the prebuy inspection. The wire may have come off due to some other anomaly, not necessarily left off by someone. And a cylinder not firing on a 4 cylinder engine when doing an ignition check has a pretty good shake to it. And a totally bad coil as mentioned here will cause 2 cylinders to not fire during the ignition check. That one is kind of hard to miss!

I really don’t understand the decision to fly when one has that kind of problem going on. Ok, maybe once in the first flight home and claim unfamiliarity, but after that it’s hard to justify.

Vic

In retrospect, it all makes sense and I obviously would not have flown had I known what was going on. I took my first flying lesson in April of last year, earned my PPL in July, and bought the plane in October. I am NOT a seasoned pilot with years of experience, nor am I a motorhead. I had never been in the plane before and did not know what was normal for it. I paid a mechanic to complete an inspection moments before I climbed into the plane for the first time with a CFI who DID have time in the plane. Given the situation, I had confidence in the airworthiness of the plane, and would have expected the CFI to point out any abnormalities.

I subsequently flew in the plane with 3 other CFIs who were all witness to the runup and mag drop, and none of them made a fuss about it. I get that all of you would have immediately identified the problem, but for a brand spankin' newbie like me, and also the CFIs I flew with--we missed it.

I was also constantly consulting with GRT, the builder, and the pre-buy mechanic. The mechanic borescoped, did compression tests, replaced plugs etc, and sent me away to fly home.

The lead didn't become disconnected - it was disconnected the first time I flew it, as evidenced by the mag drop and EGT.

I have learned a LOT from this whole experience and also from your posts in this thread. I'll definitely start watching EGTs on mag check. Thank you all for your input - and don't worry about giving me a hard time, I can take it.
 
...Verify spark plug resistance in range at each inspection as well when you clean them (aircraft plugs) or replace them (EI auto plugs).

Do not ignore when the engine is talking to you. Believe your instruments until you prove them wrong.

Carl
One thing we have discovered with the EICommander and had verified by an independent lab is that auto plugs start deteriorate at around 100 to 130 hours. It is not the electrodes that go bad, so buying high dollar plugs won't solve your issue but the ceramic insulation starts to breakdown.

We recommend you replace your auto plugs every other oil change, or annually. A full set should cost $20 or less and it is cheap insurance. Just be sure to push the plug wires all the way back on and do NOT buy plugs with twist off caps.
 
Bill - just out of curiosity... Have you seen any data that would allow you to characterize the lifecycle performance of 18mm auto plugs vs 14mm auto plugs?

There have been some good discussions here regarding using 18mm auto plugs, thanks to some vendor-supplied spark plug thread adapters failing. As a result I'm giving consideration to using 18mm plugs on my P-Mag, but won't be looking to go down that path if, for instance, the 18mm plugs have a demonstrably shorter life expectancy than their 14mm cousins.
 
To build on the OP's experiences, I should also point out that our O-360 experienced a failure of the P-Mag circuit board very early in our Phase 1 flying. It took some back-and-forth conversations with Brad at EMagAir to get to the heart of the problem. I replaced the circuit board and all is well. While it was failing I had similar high EGT while running with a rich mixture.
 
I have learned a LOT from this whole experience and also from your posts in this thread. I'll definitely start watching EGTs on mag check. Thank you all for your input - and don't worry about giving me a hard time, I can take it.

I like your attitude. Having said that, let me remind you that you bought an experimental airplane, with an experimental ignition system. It may well be that there is no other airplane in the world exactly like yours, so mechanics, cfi?s, etc., can easily be confused by what is normal, or not, for your airplane. For example, I have been in a fair number of Cessnas with a fouled plug or other malfunction, and on a mag check they ran so badly that it was clear that something was wrong. But perhaps your experimental ignition was able to smooth over the roughness due to the loss of one cylinder, I don?t know. As a non-builder, but PIC of an experimental airplane, you have a significant responsibility in your hands. Yes, consult others, but ultimately the responsibility for safe and legal flight rests with you.
 
Bill - just out of curiosity... Have you seen any data that would allow you to characterize the lifecycle performance of 18mm auto plugs vs 14mm auto plugs?

There have been some good discussions here regarding using 18mm auto plugs, thanks to some vendor-supplied spark plug thread adapters failing. As a result I'm giving consideration to using 18mm plugs on my P-Mag, but won't be looking to go down that path if, for instance, the 18mm plugs have a demonstrably shorter life expectancy than their 14mm cousins.

I use the Autolite 386 plugs on my IO-320 and have put over 300 hours on a set before changing. Plugs still looked good (no erosion of the insulator and almost no electrode wear) and performed without flaw. The 386's are hotter than I would like, but there are no other options in 18mm. I tried some NGK plugs that were cooler, but they are not resistor plugs. I added some resistor caps to compensate, but had a lot of noise, so went back to the 386's. I have done a pretty exhaustive search and found that only the 386 is offered in 18mm with a resistor. Everything else is non-resistor. I think the 18mm plugs are limited to just the tractor market. The mags don't do well with the extra resistance and the tractors don't worry about the noise.

Larry
 
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to....jbell2355
....thanks for sharing, and may we all learn something from this thread,
....
Thanks to you, for having the personal courage to put your experience out there.
You exemplify the best in a positive safety culture.
Many will learn from your event,
and you can rest easy at night knowing that,
while it may have been painful for you,
you've given back to others
and they will hopefully avoid the same pain ,thanks to you

...good day rick
 
Thanks for that feedback on the Autolite 386 plugs, Larry.

When you say they're a hotter plug than you would like, what symptoms are you seeing which drive you to this conclusion? Just plug color (white vs tan deposits), or other indications?
 
In retrospect, it all makes sense and I obviously would not have flown had I known what was going on. I took my first flying lesson in April of last year, earned my PPL in July, and bought the plane in October. I am NOT a seasoned pilot with years of experience, nor am I a motorhead. I had never been in the plane before and did not know what was normal for it. I paid a mechanic to complete an inspection moments before I climbed into the plane for the first time with a CFI who DID have time in the plane. Given the situation, I had confidence in the airworthiness of the plane, and would have expected the CFI to point out any abnormalities.

I subsequently flew in the plane with 3 other CFIs who were all witness to the runup and mag drop, and none of them made a fuss about it. I get that all of you would have immediately identified the problem, but for a brand spankin' newbie like me, and also the CFIs I flew with--we missed it.

I was also constantly consulting with GRT, the builder, and the pre-buy mechanic. The mechanic borescoped, did compression tests, replaced plugs etc, and sent me away to fly home.

The lead didn't become disconnected - it was disconnected the first time I flew it, as evidenced by the mag drop and EGT.

I have learned a LOT from this whole experience and also from your posts in this thread. I'll definitely start watching EGTs on mag check. Thank you all for your input - and don't worry about giving me a hard time, I can take it.

You have an absolutely wonderful attitude, and I have no doubt that you will continue to learn. We all have. Everyone on this forum, no matter how much experience they now have, had to learn it all. Hurray to you for your willingness to learn.

I hear you on getting so many people to look at it. My only advice as you continue to fly throughout your life is that if it doesn?t feel right to YOU, then don?t give up until it does feel right.

Vic
 
Mag Check

Not understanding the purpose of a mag check is not as uncommon as many of us believe.
A short while back, I was conducting a "BFR" , or flight review,
when my student did a mag check. He switched from "both" to each mag VERY quickly. I ask him why he cycled the mags so fast. He said "If I do it slow, it will pop and be rough".
He had never heard of clearing a fouled plug by leaning!

Another student noted the roughness of his engine during the mag check, but continued the check list. When ask what the roughness was, he replied, " Oh, that will go away about five minutes after we go to full power and take off."

Lots of student/pilots learn what to do, but not why we do it.

I hope more people will "confess" their mistakes here on this site. There are many knowledgeable folks here who are glad to help.

007
 
In early October, I signed a purchase agreement on a beautiful RV7A built by a physician here in Michigan. He had his CFI friend fly the plane up to my neck of the woods for a pre-buy inspection. I got the green light from the A&P and sent the wire transfer – the plane was mine!

The CFI and I hopped into the plane for a few landings and then I flew him back home solo. I recall during that first run-up that the engine seemed to run rough on one mag, but the CFI didn’t seem too concerned and it was my first time in the plane, so I didn’t know what was normal. On my 2 hour return flight home, all alone in a new plane, I started getting a high EGT annunciation on cylinder #4. This was disconcerting for me, having never had this kind of engine monitoring info and being new to the aircraft.

Back home, I consulted with the builder who told me that he hadn’t had this issue before. At first it seemed it had to be related to the pre-buy inspection, but what could the mechanic have done that would cause this? We did a little troubleshooting and decided it was probably a bad EGT probe. I flew the plane regularly and found that the annunciation was mostly an issue on climbout and that with proper leaning (or lack thereof), I could mostly manage the high EGT. Cylinder head temps did not appear out of line.

I flew the plane for 25 hours and brought it back to the pre-buy mechanic for a supervised oil change. I uncowled the plane and was shocked to see that the #4 high tension lead was disconnected from the upper plug on cylinder #4 (Lightspeed Ignition). The only good news was that we now knew the source of the problem. The mechanic was very nonchalant about the fact that he left the plug unplugged, and didn’t seem bothered by it at all. I wasn’t very happy, except for the fact that we thought we had solved the problem.

I flew the plane home after the oil change, excited to finally be rid of that irritating flashing red light, but it was still there! For the next few months, I swapped EGT probes, installed a new one, had them tested, checked for wiring problems, and spent a lot of time messing around trying to diagnose the problem. I was about to send the GRT EIS monitor back to be tested, when I shared some engine monitor info with Doug Hamerton at Aero Sport Power (the engine builder). He felt that, based on the data, I was leaning #4 lean of peak and that’s how/why the temp was going back in line with the other cylinders which were leaned ROP.

At this point I had put 80 hours on the engine. I had the mechanic on my field take a look and he told me I had a leaking exhaust valve, so I had him pull the cylinder. Based on the amount of carbon buildup, we decided to pull all the cylinders and have them looked at by Doug.

https://ibb.co/hAkrGJ
https://ibb.co/dPf2Oy
https://ibb.co/i3zJwJ

Aero Sport did their thing and a few weeks later the cylinders were remounted. 2 new pistons, 1 new #4 cylinder and the rest just cleaned up/painted. Once it was all put back together, I fired her up and did the ground run procedures.

Then I flew it, and still had the **** EGT problem!

This isn't the end of the story, but I’m going to stop the story here for a day or two. You should know that we did subsequently find and fix the problem. I’m curious whether anyone would have saved me all this hassle I've been through if I would have asked sooner.

And Klaus, you’re not allowed to answer.

So...what happened here?
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A disconnected plug wire would have been discovered with the first mag check when #4 cylinder cut out completely when the other mag or ignition was grounded! I guess I'm missing something here.
 
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All?s Well that Ends Well

In retrospect, it all makes sense and I obviously would not have flown had I known what was going on. I took my first flying lesson in April of last year, earned my PPL in July, and bought the plane in October. I am NOT a seasoned pilot with years of experience, nor am I a motorhead. I had never been in the plane before and did not know what was normal for it. I paid a mechanic to complete an inspection moments before I climbed into the plane for the first time with a CFI who DID have time in the plane. Given the situation, I had confidence in the airworthiness of the plane, and would have expected the CFI to point out any abnormalities.

I subsequently flew in the plane with 3 other CFIs who were all witness to the runup....

I have learned a LOT from this whole experience and also from your posts in this thread. I'll definitely start watching EGTs on mag check. Thank you all for your input - and don't worry about giving me a hard time, I can take it.

Great attitude! Thanks for posting your experience. As others have said, you are not the only one who learned from it. Obviously, you have an honesty about dealing with situations like this that is going to serve you well as you advance through your piloting days. By honesty, I mean that you see facts objectively and make decisions based on facts rather than emotions, pride, denial or any other factors that detract from good ?aeronautical decision making.?

However, one of the takeaways has to be that you need to be better educated on your power-plant,IMO. I know I do. I read a lot of accident reports and it amazes me that many of the problems start with bad engine integration or maintenance practices. I am a long way in my build from installing and running the engine, but you can bet that I will be paying close attention to every detail and will be doing it by the book!

Your comment about flying with CFI?s who didn?t recognize the problem reminds me of an experience in my student days. My CFI, and the owner of the plane, was with me while I was taxiing for take off. I noticed a problem with the nose wheel steering and told him something was wrong. I had enough experience to know something had changed. The resistance to turn inputs was rapidly increasing. He took the controls and said he didn?t detect any problems. I took the controls back and said this is getting worse. It got so bad that I stopped short of the runway. We got out and the nose wheel tire was completely flat! It had been hemorrhaging air while we were in taxi. From then on I knew that I was going to be Pilot In Command listening to my own instincts and judgment.

Thank God you had a great learning experience and that neither you or your aircraft have any scars! Blue skies!

Brian
 
Thanks for that feedback on the Autolite 386 plugs, Larry.

When you say they're a hotter plug than you would like, what symptoms are you seeing which drive you to this conclusion? Just plug color (white vs tan deposits), or other indications?

No symptoms or problems observed. Insulators stay white with some grey area. No noticeable tan color. However, no ceramic erosion is observed.

A plugs heat range reflects it's ability to remove heat from the electrode area of the plug. Cold plugs remove a lot of heat and hot plugs remove less (transfering it to the head). Each engine requires a different heat range plug to maintain an optimum plug temp in the electode area. You want enough heat retained to burn off deposits, however, if it gets too hot it can cause pre-ignition.

From my research, the 386's are hotter than the BR 8's and 9's that have been well tested for our application and hot enough to burn off deposits. This is confirmed by the white insulators. My desire to avoid the hotter plug is to reduce the potential for pre-ignition. Clearly there is some margin left, as I have no indications of pre-ignition or detonation caused by pre-ignition after 400 hours. However, the margin is smaller than it could be.

Until I notice problems, I will continue with the 386's as I would like to avoid the issues with the adapters. However, on the 540 I am building I will likely get the adapters and go with the cooler 14mm plug options.

Larry
 
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How I missed the dead plug on mag check

--------------
A disconnected plug wire would have been discovered with the first mag check when #4 cylinder cut out completely when the other mag or ignition was grounded! I guess I'm missing something here.

A few of you seem perplexed as to how a cold plug could be missed on mag check. I'll try to explain.

The aircraft has one Lightspeed Plasma III ignition and one Slick Mag. Up to this point, I had only flown in aircraft with mags and was accustomed to an RPM drop of up to 125 RPM when grounding a mag. The run-up checklist in the POH for my new plane indicated that I should be looking for a symmetrical mag drop of up to 125 RPM, which is exactly what I got. Yes, the engine seemed a bit rough when the mag was grounded, but it wasn't like the plane was shaking apart. You might be surprised by how much a single electronic ignition running three plugs acts like a single magneto running four. Yes, something didn't seem exactly right, but given all the circumstances I described before, it became the norm for me in this plane.

Now that I have read more about the electronic ignition and talked to Klaus, I understand that there should be virtually no RPM drop when running only on the electronic ignition. With the experience I have now - seeing how well the engine runs on the Lightspeed alone - I would absolutely recognize this problem were it to occur again. Experience can be a really great teacher.

I believe that the POH for my plane was borrowed from another builder and was not adjusted to account for the fact that there is an ignition and a mag. I should not have been looking for a symmetrical RPM drop and certainly not 125 RPM when grounding the mag.

Does that make any more sense?
 
I like your attitude. Having said that, let me remind you that you bought an experimental airplane, with an experimental ignition system. It may well be that there is no other airplane in the world exactly like yours, so mechanics, cfi?s, etc., can easily be confused by what is normal, or not, for your airplane. For example, I have been in a fair number of Cessnas with a fouled plug or other malfunction, and on a mag check they ran so badly that it was clear that something was wrong. But perhaps your experimental ignition was able to smooth over the roughness due to the loss of one cylinder, I don?t know. As a non-builder, but PIC of an experimental airplane, you have a significant responsibility in your hands. Yes, consult others, but ultimately the responsibility for safe and legal flight rests with you.

I appreciate your comments Bob and you make a great point. I guess it's clear that at the time of purchase, I was, and maybe still am, not up to the responsibility of ensuring safe flight. In my non-aviation life, I am accustomed to consulting with those more knowledgeable than me and placing some amount of trust in those individuals' hands.

In this case, I spent some time getting to know the builder and visually inspected the quality of his work. I paid an A&P to do a thorough inspection of the aircraft (and he confirmed the quality of the build). And I flew with a CFI who had some time in the aircraft. Each of these individuals knew and understood far more than me about this aircraft in particular, and aircraft systems in general.

I knew that my familiarity with the plane was limited, so I had all of these resources involved to help make sure that flight in the aircraft was safe. However, I still failed to ensure safety. It wasn't the fault of any of these fine gentlemen that I flew around for 80 hours with only 7 plugs firing - it was my fault as PIC. I get that. You don't know what you don't know, until you do, then you post it on vansairforce. :)

So many things had to line up just the wrong way for this whole ordeal to happen the way it did. If only I had flown the plane before the pre-buy, I would have known what was normal and recognized the problem. If only the builder had ferried the plane to the pre-buy instead of his CFI, he would have recognized the problem when we did our first run-up. If only my A&P had gotten in the plane and heard it run on the ignition, maybe he would have recognized the roughness.

Anyway, we got it all working now, and I'm having a boatload of fun flying that little plane around. I'm grateful for this community and will remember to come back the next time I have a squawk like this. Thank you for your kind words, and also your harsh words.
 
Klaus has really good manuals provided for this system when it?s installed. They should be with the original aircraft paperwork. If you need a copy I?m sure he will provide it.

In the document there are clear warnings about operating the system with disconnnnected or broken leads that can damage the ignition coils.

Also, there are special considerations regarding the spark plug heat ratings not discussed here.
 
You might be surprised by how much a single electronic ignition running three plugs acts like a single magneto running four.

It's a waste spark CDI.

The initial symptom may have been a single plug not firing, as the disconnected plug wire arced to the nearest engine metal. If so, the paired plug on that coil would have fired normally...until the excessive voltage rise burned though the insulation on the secondary windings. Now the coil is failed. The result would be two dead cylinders when the mag was grounded. It would be hard to overlook.

I don't recall reading how it was eventually determined you had a bad coil, or what else was replaced at the same time. Can you fill the blanks?

And BTW, why replace two pistons?
 
A few of you seem perplexed as to how a cold plug could be missed on mag check. I'll try to explain.

The aircraft has one Lightspeed Plasma III ignition and one Slick Mag. Up to this point, I had only flown in aircraft with mags and was accustomed to an RPM drop of up to 125 RPM when grounding a mag. The run-up checklist in the POH for my new plane indicated that I should be looking for a symmetrical mag drop of up to 125 RPM, which is exactly what I got. Yes, the engine seemed a bit rough when the mag was grounded, but it wasn't like the plane was shaking apart. You might be surprised by how much a single electronic ignition running three plugs acts like a single magneto running four. Yes, something didn't seem exactly right, but given all the circumstances I described before, it became the norm for me in this plane.

Now that I have read more about the electronic ignition and talked to Klaus, I understand that there should be virtually no RPM drop when running only on the electronic ignition. With the experience I have now - seeing how well the engine runs on the Lightspeed alone - I would absolutely recognize this problem were it to occur again. Experience can be a really great teacher.

I believe that the POH for my plane was borrowed from another builder and was not adjusted to account for the fact that there is an ignition and a mag. I should not have been looking for a symmetrical RPM drop and certainly not 125 RPM when grounding the mag.

Does that make any more sense?

I can verify on my aircraft with 10 to 1 pistons and dual light speeds at 1700 RPM doing a mag check the engine is very smooth on 3 cylinders. Watching for the EGT rise is how I perform my run ups.
 
... Given the situation,I had confidence in the airworthiness of the plane, and would have
expected the CFI to point out any abnormalities...

This is a great discussion on the importance of preflight checks. Through this whole discussion this statement has stood out the most, mainly because it is the exact opposite from my focus during preflight.

I approach the preflight checks (before taxi, taxi, and before takeoff) with the mindset that the airplane is not airworthy. The checks slowly put together the "proof" that it actually is.

Knowing why every line item is in the checklists is the key. How are you supposed to determine if sub-par performance of a checklist item is a "safety of flight" issue unless you understand what it is telling you?
 
It's a waste spark CDI.

The initial symptom may have been a single plug not firing, as the disconnected plug wire arced to the nearest engine metal. If so, the paired plug on that coil would have fired normally...until the excessive voltage rise burned though the insulation on the secondary windings. Now the coil is failed. The result would be two dead cylinders when the mag was grounded. It would be hard to overlook.

I don't recall reading how it was eventually determined you had a bad coil, or what else was replaced at the same time. Can you fill the blanks?

And BTW, why replace two pistons?

Thanks for your comments Dan. No pistons were replaced...I misunderstood my mechanic and have since gone back to the engine shop to verify exactly what they replaced.

I figured out it was the coil by talking with Klaus at Lightspeed. I explained all that had happened up to that point and he immediately recognized that the coil would be burnt out and told me so.

He did not mention anything about the burnt up coil also killing spark to #3. Based on my observations, I do think that #3 was firing.
 
In 35+ years of having one LSE on the planes, I've learned (the hard way) to always carry a spare new coil. One failed mid-flight, the other on the ground. Two failures in ~5,000 flight hours.

Just for reference, 2 Slick mag failures in the same 5,000 hours.
 
I'll ask again just in case this was missed... Does anyone know what the light-coloured buildup is on the face of the pistons? Is it lead?

IMG_0931.jpg
 
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