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Top Cat 10-15-2017 07:12 PM

Oil pressure went to zero, fuel pressure maxed out
Today cruising at 5500ft oil pressure suddenly started fluctuating on the low side before going to zero with red X. Along with continuous audible warning “Oil Pressure”.
Very shortly after this my fuel flow went to the upper green limit then into caution along with “Fuel Flow” audible warning.

The engine itself performed normally, no vibration, ran smoothly, no obvious oil leaks. Nothing else abnormal.

On descent to the field at above idle the oil pressure indication returned to normal as did fuel pressure. Landing and taxi uneventful and post flight inspection showed no oil loss or anything else abnormal.

Ran it by my Rotax trained and qualified mechanic and his suggestion was to contact Dynon Tech Support which I will do tomorrow as it sounded to him like it was a Dynon issue.

Thought I’d post the experience here to ask for suggestions and/or comments.
Thanks in advance e.

DHeal 10-15-2017 08:53 PM

A big red X usually means you have an electrical circuit problem. If you did in fact lose OP then the reading would likely go to @ 0 psi (+ 2-3 PSI) without a red X. Check all of your OP and FP wiring. Could be a sender but more likely a poor wiring connection.

Top Cat 10-15-2017 09:03 PM

Thanks for the info.

Coincidentally I’d just uploaded the latest Dynon software update.

I did wonder about a poor connection but then why would readings be normal at lower power and why does fuel flow increase whilst oil pressure goes down with the same increase in power? How could they be related?

I see by your address that you’re near Santa Rosa? I hope all is well with you and your family with all the tragic fires.

DHeal 10-15-2017 09:20 PM

Thanks Top Cat for the kind thought -- we are fine but a number of our RV family here in SR have lost theirs homes, cars, household contents, etc. The fires have been horrific.

Electrons are funny things -- all sorts of strange instrument indications can be seen if the wiring is not 100% up to snuff. In my experience, the RV-12's FP can be erratic for "yet-to-be-fully-understood" reasons -- never seems to interfere with the engine's operation however.

pilot2512 10-15-2017 09:24 PM

I would check your grounds really well.

TS Flightlines 10-16-2017 07:18 AM

Howard--the fuel pressure indicated high? Does sound like a instrumentation issue to me. I wonder if yo would mind sharing your 'normal' pressure indications with us.

Top Cat 10-16-2017 09:21 AM

Normally oil pressure is around 60 psi and fuel flow about 5.2.

When the oil pressure started fluctuating it dropped to almost zero went up and down until resting on zero flowed by the red X and continuous audible “oil pressure” warning.

The fuel flow to top of green then to the upper caution range followed by “fuel flow” warning.

Reducing throttle brought everything back to normal and that’s the part I don’t get, especially if it’s a bad connection.

Appreciate the help!

rvbuilder2002 10-16-2017 09:49 AM


Originally Posted by Top Cat (Post 1211301)
Very shortly after this my fuel pressure went to the upper green limit then into caution along with ďFuel PressureĒ audible warning.


Originally Posted by Top Cat (Post 1211403)
The fuel flow to top of green then to the upper caution range followed by ďfuel flowĒ warning.

Reducing throttle brought everything back to normal and thatís the part I donít get, especially if itís a bad connection.

Was it high fuel pressure, or fuel flow?

An intermittent connection usually means something is influencing the connection to make and break. That influence often times is vibration. Vibration changes with engine RPM.

Because you have more than one indication changing at the same time, something that is common to both should be looked at (system grounds).

Mich48041 10-16-2017 09:57 AM

My average fuel pressure with engine off and electric pump on is 2.6 psi.
At cruise with both pumps on, the average pressure is 4.3
Keep in mind that the senders are notorious inaccurate. The actual value displayed is meaningless without being verified with a calibrated gauge. It is up to the pilot to learn what is normal in her plane, then take notice if the pressure deviates from normal.

Top Cat 10-16-2017 11:32 AM


Sorry yes I meant fuel FLOW went high to the max limit. Ill correct my post.
Now I can't recall if the audible was fuel flow...either way there was a warning audible concurrent with the incessant" oil pressure" warning.

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