Originally Posted by schaplerrh
Jesse, I'm seeing excessively high EGT but normal CHT on all four cylinders when I trying going LOP. Engine roughness hasn't been a problem while leaning at cruise -- may because temps climb so fast I quickly richen the mixture to cool things down. I have the GRT engine monitor remotely mounted with AFS EFIS displays. Any ideas? Forgot to mention: IO-360 with MT CS acro prop and properly timed, good old fashion mags.
Originally Posted by Jesse
How's high is excessive? If you are not above 65% power and CHT's are fine, then I wouldn't worry about it.
Scott and Jessie,
I had all of the symptoms you have been describing also last month. High EGT but normal CHT on #3 cyl. Going LOP would have #3 EGT bouncing around while the others were rock solid. Went through all the same troubleshooting thoughts. Spark plugs fouled? Cleaned aviation plugs and replaced auto plugs? Nope! Bad EGT probe? Swapped them around. Nope! Finally removed all fuel injectors. Closely inspected each injector but could not see anything abnormal at all. Cleaned them with ultrasonic cleaner anyway. Bingo! Runs like a top now. Even though there was nothing visual blocking the injector there must have been something in there. Everything is great now.
So if anyone is seeing erradic EGT readings you might think about fuel injector cleaning as a good place to start.
Live Long and Prosper!