Single Cylinder EGT Creeping Up - Why?
I have a 2019 LSA with a 912IS engine. Over the last few months on long cross country flights I have noticed a consistent issue.
On my #4 cylinder, at altitude (7,500msl or higher), the EGT temps will slowly rise by themselves and independent of the other cylinders. This is level cruise, WOT, 5450RPM, full rich. The other cylinders get to a certain temp and basically stay there without moving. There may be an 80-100 degree difference between the others, but they don't really move at all.Over a period of about 10 minutes the temps on the #4 will creep up until I get a warning at 1600f. If I cut the throttle to 5,000rpm (eco) and then go back to full power, the EGT on #4 will drop back down with the rest. But over the next 10 minutes it will creep up again. This cycle just repeats itself.I have replaced both fuel injectors on the #4 cylinder, but that has not had any impact. The plugs are new on all cylinders. After inspection, they all seem fine and consistently colored.
Anyone have any thoughts of what may be going on? The higher the altitude, the quicker this issue seems to happen. At lower altitudes, there is less of a spread but as I recall the base EGT for all cylinders appears to be higher. (I'll confirm later...thats just from memory).
I have new EGT probes, in case it is a simple issue of just the probe.Should I just replace that one probe on #4 and test, or should I swap the probe with another cylinder?
My concern about swapping, is that as I recall...messing around with any EGT probe basically causes them to fail shortly after replacing them. So swapping means I will have to replace two probes vs. just replacing the one I think is bad.Any other thoughts come to mind?
