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CHT Fluctuations
So my #2 cylinder CHT will set off a shock cooling alarm right from the start through the flight. I was fairly certain it was the probe. It would climb several degrees and come right back to what I figured was normal.
I finally go around to swapping the #2 for #4 probes and went for a flight. Much to my surprise the problem did not follow the probe, issue the same on cylinder #2. I recently had morning sickness on this cylinder and did the ream procedure, exhaust valve was definitely stuck. I had to use a brass drift to get the thing out. After the reaming, smooth as butter. I don't think these two things are related, but maybe. My only thought is that some sort of electronic interference is causing the fluctuation. Maybe from the plug wire. It the only thing I can think of that would cause this. Today I had a couple of fluctuations with more movement that before. At a steady CHT of 377 I had a swing up to 399 which set off the high CHT alarm. So as anyone experienced anything similar? Mags are good (Dual Pmags). Just flew today and did a LOP mag check at 8500' and it was good. I still need to download the data. Previously this was an intermittent problem, it would be there one flight then not the next, but lately it is there all the time. Thanks for any help. |
Question...
When you swapped the probes, did you take each one loose from its wiring and put it on the other leads, or merely reroute them without taking them off?
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The temperature swings are too rapid to be actual heat changes in the cylinder. |
I had a similar problem with EGTs on my new 10. I had bundled the EGT wires with the ignition wires for a short distance. Unbundling solved the problem. Symptoms were a dead giveaway, as the intermittent movements/swings were more rapid than could realistically be produced from normal, operational temp changes. My swings were withing approximately 10% of actual.
That said, I have dual EI and these provide greater spark energy than mags. Not sure this would have occurred with mags. Larry |
Maybe I?m confused...
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I am going to try and move the ignition wire and see what happens. I was hoping someone may have had the same issue and could confirm my hypothesis is plausible. Cheers |
Engine monitor label
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Perhaps you did rewire, if so, ignore what I said above. |
If you fly on one mag, does the problem go away?
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Check the terminal crimps
I just had an issue with the #1 CHT probe on my Dynon Skyview. After taking off from my destination airport the reading went from my normal 350 ish up over 400 then up over 500. All else was normal so I continued home. After landing, having previously read about many terminal crimp issues, I recrimped the factory crimps on the #1 CHT leads. All back to normal for the last 5 hrs since.
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Check for a bad ground.
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