Oil pressure went to zero, fuel flow went max

[Tigermoth]

In cruise today oil pressure suddenly began to fluctuate and then went to zero with red X shortly followed by fuel flow increasing to max. With both got audible caution warnings.

Engine continued to run normally. On descent with power reduced indications returned to normal but as power increased the faults returned.

Landing and ta I indications were normal and post flight oil quantity was as was pre flight and no other problems found after removing cowling (RV-12).
Subsequent start up, taxi, and run up normal. after lift off oil pressure warning andfuel flow warning returned and went away at low and reduced power.

Prior to flight I had uploaded latest routine software update from  Dynon.
I discussed problem with my Rotax trained and qualified mechanic who suggested it was a Dynon issue.

Any ideas?

 

[Garrett]

I just went thru a similar situation with 3 instruments, in all 3 it was wiring connection issues.

 

[Tigermoth]

Thanks for the info.

I get that a loose connection could cause erratic readings but don’t quite understand why it returns to normal at reduced throttle.

 

[Garrett]

I also remote mounted the sending units on the firewall. Vibration and the heat cause them to fail prematurely. This might be the problem you are having.

 

[Garrett]

I believe this is even suggested in the Skyview install manual for oil pressure. At least it was when I installed Skyview 3 years ago.

 

[Tigermoth]

My plane is an RV-12...built by Vans as an SLSA

 

[Dynon]

So there are a few things that it can be, and it might be tricky to figure out. First, know that both the fuel flow sensor and the rotax oil pressure sensor use a 12V line. This is often provided by a 12V power supply from the Dynon EMS module (I'm not certain how Vans hooks this up, you'll want to check with them). If something were going on with that, particularly an intermittent connection, that could cause oil pressure to fall and fuel flow to read high (because the oil pressure sensor needs power to generate an output, so an intermittent 12V line could look like a low signal, while the fuel flow sensor counts pulses, so intermittent 12V might cause it to look like it's generating extra pulses. So that's one possibility. There's also a chance that the oil pressure sensor is having some failure mode that is causing it to affect other things. We're not experts in that sensor though (it's a Rotax-provided part). Do you know how high fuel flow went? In order of likelihood, there's a high chance it's either wiring or something going on with the oil pressure sensor. There's a very low probability that it's the fuel flow sensor - we think that's probably being stimulated with extra pulses from whatever else is going on. The EMS itself is not the most likely culprit here either. You may want to call our support team at 425-402-0433 so that we can help you more personally with this one. If you had a user datalog or Dynon diagnostic file, that could possibly help us troubleshoot with you too.

 

[Tigermoth]

Thanks I did call and speak with a tech Support today. Will get a diagnostic file uploaded ASAP.