capacitance probe calibration problem

[jamesgreen]

D100,D120 RV7 with vans capacitance plates installed. Dynon signal convertors.
Finished calibration last night.
After draining L tank, it still showed full. R tank correctly showed full.
This morning, on turning on power both tanks showed empty but slowly started to show increased quantity. After about an hour they both showed full.

Before I tear my wiring apart, are there any clues here as to my mistake?
One place where I deviated from the instructions was to ground the signal converters to the airframe.
This was done with engine off. Nothing powered except D120.

 

[dynonsupport]

What do you mean that you "grounded the signal converters to the airframe"?

Do you happen to have the voltages that the system listed while you were doing the calibration? These would be helpful for us to determine what is going on.