Dynon D180 OAT readout shows 64 C

[shirschi]

Dynon D180 installed in Europa XS with Rotax 914 engine.  OAT readout starts out at ambient temperature before engine start.  Once the engine is started the readout climbs to 64 C.  The OAT probe is bottom RT fuselage (opposite side of the engine exhaust).

I bought the aircraft from the original builder.  I didn't install the D180, but I do have the installation manual and a diagram of the wiring inputs to the unit.

Any suggestions on where to start fixing the problem? 

 

[jakej]

Is the probe getting cowl outlet warm air from the engine ? A picture of the probes exact location in relation to the cowl could help

 

[jaba-who]

Step 1. Prove it’s not positioning and reading true temp.   Unscrew the probe from skin of aircraft & pull it inside and run again. If the new temp doesn’t change to 64 then the problem is it’s getting engine heat and you need to change probe location. If it still changes to 64, it’s a dynon problem. I have found fixed instant and constant temp readings are technical not position errors. Position error you would expect some fluctuation with conditions. But just check for position to be complete.

Step 2. Assuming it’s a dynon problem. Most likely a wiring or connection problem. Pull apart and clean any joins in the temp probe wiring first.

Step 3. Then if that fails start doing all the wiring joins. Clean and Secure all earth wires first. Dynons can get all sorts of odd readings on any parameter if any of the earth lines are not secure and at equal earth potential. Most common one seems to be oil temps read weird when anything else goes out but can be anything.