This is a long post..... but PLEASE read it, and if you have some ideas on what might be happening ...we would appreciate the feedback
We have been trying to diagnose an oil pressure issue for the last few weeks that shows up as fluctuating oil pressures.
The first chart shows the oil pressure and oil temperature during the first event. The response of the oil temperature moving in lock step with pressure had us a bit puzzled..how much lag should there be? and worried at the same time.
We replaced the VDO sensor to see if that was the issue and flew again.
Here is the plot of OilP and Temp on the first event flight:
After replacing the VDO and taking a short flight
Pressures seemed normal:
Thinking all was OK, we took the airplane the following weekend, and all was operating normally, until ALL engine parameters went INOP at the EFIS.
That is definitely a data signal issue from the RDAC to the EFIS. We pulled the data link wire and inspected the connection, and found a significant loss of strands at the screw in connector at the back of the EFIS. Refinished the ends, laced the data wire in more places, and reinstalled.
That brings us to yesterday for the next test flight.
I was doing a local short flight near the airport to check things out again. Everything seemed nominal, until about ten minutes in, where I noticed that instead of a normal 85PSI at 23 inches/ 2400 I was at 60 PSI.
HMM. Something is up, so I executed a return to base to investigate.
The Top set of plots are oil pressure and Temp, Manifold pressure, and CHTS during this last flight.
I have also included a set of plots from last year in May, showing nominal for comparison.
After the flight, I added a mechanical pressure gauge and ran the engine up on the ground to 17MP and 1900 RPM. Oil pressure on the EFIS and the mechanical matched at 90 PSI, and I let the oil temps get to 120. (so not very hot yet)
Now the big question (s) ::::
What is happening?
IS there an impending BAD failure coming?
Could this be caused by a bad vernatherm?
Have we already damaged our engine?
Could it all be an electrical issue?
Oil Pressure and Temp problem
Manifold Pressure during oil pressure event
CHT during Oil pressure event
Oil Pressure and Temp Normal
Manifold Pressure Normal