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?
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?