Originally Posted by bizpilot
I know this thread has been extensively discussed last fall, but I have a different question. Our RV14A IO390 runs cold. Typically front cylinders 1and 2 low 200’s CHT’s, rear’s 3 and 4 mid to upper 200’s. This is at cruise. Almost never see 300 CHT’s. The CHT input curves were switched in our G3X from K to J or vice versa (can’t remember) then the CHT’s look normal. The ones with the cold numbers were the correct for our installation.
Any input appreciated.
Highly suspect in my opinion. Type K thermocouple wire must not be mixed with Type J. The correct wire must be used with the correct probe, then configured properly in the G3X. Wire color is the easy way to tell which you have. Read this builders note from SteinAir:
Also, I recently learned there are some grounded and ungrounded CHT probes. If I remember correctly, Advanced Flight Systems used ungrounded Type J CHT probes. Those WILL NOT work with a G3X. I had to change out 4 probes on a recent build to Grounded Type J (so I could use all my existing wiring behind the panel) and that corrected the false indication.
Low 200's at any power setting other than idle, in the winter, doesn't seem possible.