Purging Lubrication System

Why not just remove the sensor and connect up the 8 psi feed that you have? That should indicate about 0.5 bar. Don't forget to ground the sensor body to the crankcase to complete the circuit. At least you would know that your sensor and EMS are fully functional.

This would depend a little on how fast you turn the prop. I turn the prop like you have it set up about 50-60 times per minute and do it for 80-90 revolutions. I can usually see around 50+ psi. I don’t usually watch for the pressure, but I did do a 15 plane study about 15 years ago doing this. If you had go oil return and checked the valve tappers then try a start to look for your pressure.

p.s.

Make sure all your appropriate power on the instrument panel is on.

Did the"purge" on my yet to be started ULS, the other day - I turned the prop (great work out), the better half (wife) watched the Dynon. 

Dynon started reading pressure after a few turns. Continued to rise, then stabilise. Reading, from air pressure (10psi), continued after stopped turning prop, until  air turned off. 

Thanks to everone for the great advice.  I first purged the engine in January with no problem. Oil pressure reading quickly went to about 50 psi. I successfully started after the purge.  Only ran the engine for about 3 minutes just to verify correct hook up.  Since then, I disconnected  the oil cooler to modify the bracket. The plane set for about 3 months. Now trying to purge, start and run the engine.  I wonder if the earlier oil purge, short engine run, and long wait had an effect on the oil pump, the oil pressure sensor or the engine.