Walt Shipley
Active Member
In my quest to eliminate high fuel pressure warnings on my Dynon FlightDek
D180, as some of you know who have tried to help, I think I have narrowed the problem down to two possibilities:
First, with either the original VDO sensor or the Kavlico sensor, my fuel pressure from idle to WOT will be in the range of 5.2 psi to 5.9 psi. The latter of course, sets off the overpressure warning. However, when I hooked up the fuel pressure hose to a mechanical pressure gauge (new, good quality, oil filled), my fuel pressure stayed in the green, registering between 4-4.8 psi.
Second, I've removed the sensors from the fuel pressure line numerous times and I always get a small amount of fuel out of the hose that is discolored (orange). At first there were some tiny pieces of debris that looked like white strings. The debris seems to have cleared up now with running fuel through the hose via the boost pump, but the initial orange color remains, in the first ounce or two that comes out.
So, in the first case I seem to have the possibility that the overpressure lies in the Dynon. In the second, maybe there is enough debris coming through the pressure hose to partially plug up the sensor.
It's occurred to me that the hose debris and fuel discoloration could be the same as the problem that prompted the recent AD with the pressure hose coming off the mechanical pump of the Rotax.
I know there have been some issues amont RV-12 builders with high fuel pressure alarms, but it seems that most of them have been solved by switching to the Kavlico sensor, or by installing a replacement VDO sensor, or by using capacitors to smooth out the jerky fuel pressure needle. I've tried everything thing I can think of and so far, the only thing that works for me is to go into the Dynon and set the redline value of 5.8 psi to 6.0 psi. That keeps Betty off my back but doesn't solve the problem.
Any input will be welcome. Right now I plan on calling Mike Huff at Dynon and see what suggestions he might have.
First flight held up .....
Walt Shipley
P.S. I removed the carb float bowls and the fuel was clean and without debris
D180, as some of you know who have tried to help, I think I have narrowed the problem down to two possibilities:
First, with either the original VDO sensor or the Kavlico sensor, my fuel pressure from idle to WOT will be in the range of 5.2 psi to 5.9 psi. The latter of course, sets off the overpressure warning. However, when I hooked up the fuel pressure hose to a mechanical pressure gauge (new, good quality, oil filled), my fuel pressure stayed in the green, registering between 4-4.8 psi.
Second, I've removed the sensors from the fuel pressure line numerous times and I always get a small amount of fuel out of the hose that is discolored (orange). At first there were some tiny pieces of debris that looked like white strings. The debris seems to have cleared up now with running fuel through the hose via the boost pump, but the initial orange color remains, in the first ounce or two that comes out.
So, in the first case I seem to have the possibility that the overpressure lies in the Dynon. In the second, maybe there is enough debris coming through the pressure hose to partially plug up the sensor.
It's occurred to me that the hose debris and fuel discoloration could be the same as the problem that prompted the recent AD with the pressure hose coming off the mechanical pump of the Rotax.
I know there have been some issues amont RV-12 builders with high fuel pressure alarms, but it seems that most of them have been solved by switching to the Kavlico sensor, or by installing a replacement VDO sensor, or by using capacitors to smooth out the jerky fuel pressure needle. I've tried everything thing I can think of and so far, the only thing that works for me is to go into the Dynon and set the redline value of 5.8 psi to 6.0 psi. That keeps Betty off my back but doesn't solve the problem.
Any input will be welcome. Right now I plan on calling Mike Huff at Dynon and see what suggestions he might have.
First flight held up .....
Walt Shipley
P.S. I removed the carb float bowls and the fuel was clean and without debris
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I assumed the color was from proseal. Who knows?
