This can mean that the engine isn't extremely well grounded to the rest of the electrical system, which causes small voltage variances across the electrical system to be registered as a temperature change. Are you using the type 5 sensor currently? Here are the list of supported sensors:
Type 1: Dynon P/N 100409-001 (sensor we sell. they're also pretty susceptible to grounding issues)
Type 2: Dynon P/N 100409-000 (sensor we sell. they're also pretty susceptible to grounding issues)
Type 3: GRT FT-LC-01 (two wire probe with grounding wire; not very susceptible to grounding issues)
Type 4: Rotax pre-installed (this comes on Rotax 912 engines and from experience, doesn't seem to be too susceptible to grounding issues, but that can be an artifact of the consistent installation. Your mileage may vary. It's available aftermarket but you'd need to thread adapt it)
Type 5: Jabiru pre-installed (this is what you might be using it looks similar (but is not a drop-in replacement) in grounding susceptibility to the sensors we sell). I don't remember: does the Jabiru oil temp sensor have a dedicated ground wire?
Type 6: Chevrolet LS7 pre-installed (this was a custom application; not much data on it)
