Free Flight, Free Speech

The PA-20 and PA-22 both don't have functioning oil pressure gauges. I looked in the oil.xml file and it points to engines/engine/oil-pressure-psi. In the internal properties the value given is: '' (none). Therefore, there is no value the oil pressure gauge can display.

How can we/I fix this?

Please help.

jsbsim or yasim flight model ?

https://github.com/FGMEMBERS/pa20

https://github.com/FGMEMBERS/pa22

Both Yasim.