D-180 Alarm for High Fuel Pressure

[Piper_J3]

I bought a flying Van’s RV-12 with Rotax 912ULS. Total time on engine is 70 hours. The engine has the new style fuel pump 893110 S/N 13.4493. The engine monitor is a Dynon D-180. I am getting alarms for both high fuel pressure and high fuel flow. Pressure has been as high as 12psi and fuel flows as high as 13gpm. These conditions are spikes. Normally the fuel pressure is steady ~ 7psi and fuel flow is 4-5gpm in cruise flight. The RV-12 has an electric fuel boost pump that is always on. I have pulled the electric fuel pump fuse on occasion and this seems to reduce total fuel pressure. The pressure increases when throttle is reduced in the landing pattern. Sometimes the pressure may also spike in cruise flight but not very often. High fuel flow only happens once in awhile and only happens during cruise flight.

I’m trying to troubleshoot this problem. I’ve been told that the mechanical fuel pump is fixed pressure output and most likely not causing high fuel pressure. Does this problem sound like pressure sensor going bad? How about ground problem or EMF generated by parallel wires? What would the Dynon display if wire connection was intermittent?

Thanks in advance…

 

[Dynon]

If intermittent or disconnecting, you'd get readings that rail out or red X, not just read somewhat high. So it's not that. Are those fuel pressure and flow spikes happening at the same time? If so, the pressure sensor (which gets a variable voltage) and the fuel flow sensors (which count pulses) work so differently that it's likely pointing to a real issue in the fuel system that the system is correctly measuring. In that case, you'll need to drive that to root cause with Van's and perhaps Rotax.

 

[Piper_J3]

Thank you, that points me in right direction...