EGT readings.

[DaveJnr]

I have a new installation in my aircraft. The engine has only been ground run a couple of times. I notice that the EGT readings give a fairly sensible ambient OAT before engine start. However shortly after engine start all four reading stabilise at around -95 Celsius.
This is a ROTAX engine and the plug harness was wired by me. Have I done something stupid like wired the probes the wrong way round, or is something else amiss?
Thanks

 

[dynonsupport]

This most likely means they are wired backwards.