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Old 10-30-2020, 09:54 AM
f14av8r's Avatar
f14av8r f14av8r is offline
Join Date: Apr 2012
Location: Tampa (Wimauma actually)
Posts: 433
Default Fuel Pressure unreliable

Hello All,
Looking for some help troubleshooting a fuel pressure issue. My RV-8 has an IO-360 being monitored by my EFIS, an Advanced Flight Systems 3400s with the AF-3400 Engine Monitor Package AF-3400-EM-4.

I acquired the airplane in May of 2019. The fuel pressure readout has been a constant issue and I'm trying to focus on getting it fixed.

Here's the problem. The fuel pressure reading is accurate and reliable when I'm running just the engine driven pump, or just the boost pump (on the ground obviously) but when I have both operating, such as for takeoff and landing, the fuel pressure readout goes haywire. It runs into the triple digits, then back down to zero and, eventually, the indication gets XXXed out.

I have the standard VDO sensor installed. I've replaced the sensor. No difference. I've checked the wiring. All good. I've checked the EMS setup. All good. I've checked that the reducer is installed in the line from the pump to the sensor manifold.

I'm considering replacing the VDO with the AFS/Dynon Kavlico pressure sensor. I would have already tried this but it the Kavlico requires +5v which I'll have to run from the EMS. That's a lot of work and the opportunity for maintenance induced failures are always high anytime one starts mucking around behind the panel!

What other troubleshooting steps would you take? Any thoughts / ideas much appreciated.

Randy King
Tampa (Wimauma), Florida
RV-4 N212CS (sold)
RV-8 N184RK (flying)
Flying an A320 to pay the bills
Exempt and gladly donating anyway - Current through March 2025
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