Oil pressure fluctuations
in 912 / 914 Technical Questions
7 years ago
Hello! We are desperately looking for some good idea ...
Situation: Rotax 912 ULS from 2007, 600h, with the old VDO oil pressure sensor. Dynon D180 as EFIS/EMS instrument
-Shortly after takeoff oil pressure fluctuations from normal 3.x to 1.x. Not reproducible on the ground or at the next test flight.
-Shortly after takeoff again the same oil pressure fluctuation.
Changed the Sensor (as the most probable and simple cause), damaged the oil pump housing, therefore
-new-type Rotax sensor
-new oil pump housing
-Dynon factory firmware update, configuration for new type sensor.
-"Similar" oil pressure fluctuations when oil is hotter than 60 deg C/140 deg F.
-cleaning of the oil pressure valve ball: "little better"
-replacing the oil pressure valve ball with the mushroom type: "again a little better"
-Using a bluetooth oil pressure sensor parallel to the installment above:
Fluctuations in the Dynon-Rotax-sensor installment, no fluctuations with the Bluetooth instrument.
=> ???
You may see this in the film:
Setup for Rotax-Sensor, 18 Mb
Wiring
So
a) both the old VDO and the new Rotax-Sensor could be defective.
b) the pressure valve could be defective (but the outer part, the oil pump housing is new and the ball is replaced with a mushroom type. For this hypothesis, the bluetooth instrument has to be heavily damped/averaged. Values don't look like that.
c) the Dynon instrument is crazy (but as far as I understood this with the VDO sensor voltage is measured, with the new sensor current is measured. Different setup though). All other values are displayed without fluctuation.
d) something with ground/plus wiring is wrong. But the wiring has been checked/redone
e) the new sensor transmits some spikes/dips and the old sensor was defective?
If we (intentionally) wrongly configure the Dynon instrument for a Dynon-supplied Kavlico-Sensor, the values are way off (6.something) but stable and proportional to the bluetooth-instrument.
Does all this this makes any sense to you?
Situation: Rotax 912 ULS from 2007, 600h, with the old VDO oil pressure sensor. Dynon D180 as EFIS/EMS instrument
-Shortly after takeoff oil pressure fluctuations from normal 3.x to 1.x. Not reproducible on the ground or at the next test flight.
-Shortly after takeoff again the same oil pressure fluctuation.
Changed the Sensor (as the most probable and simple cause), damaged the oil pump housing, therefore
-new-type Rotax sensor
-new oil pump housing
-Dynon factory firmware update, configuration for new type sensor.
-"Similar" oil pressure fluctuations when oil is hotter than 60 deg C/140 deg F.
-cleaning of the oil pressure valve ball: "little better"
-replacing the oil pressure valve ball with the mushroom type: "again a little better"
-Using a bluetooth oil pressure sensor parallel to the installment above:
Fluctuations in the Dynon-Rotax-sensor installment, no fluctuations with the Bluetooth instrument.
=> ???
You may see this in the film:
Setup for Rotax-Sensor, 18 Mb
Wiring
So
a) both the old VDO and the new Rotax-Sensor could be defective.
b) the pressure valve could be defective (but the outer part, the oil pump housing is new and the ball is replaced with a mushroom type. For this hypothesis, the bluetooth instrument has to be heavily damped/averaged. Values don't look like that.
c) the Dynon instrument is crazy (but as far as I understood this with the VDO sensor voltage is measured, with the new sensor current is measured. Different setup though). All other values are displayed without fluctuation.
d) something with ground/plus wiring is wrong. But the wiring has been checked/redone
e) the new sensor transmits some spikes/dips and the old sensor was defective?
If we (intentionally) wrongly configure the Dynon instrument for a Dynon-supplied Kavlico-Sensor, the values are way off (6.something) but stable and proportional to the bluetooth-instrument.
Does all this this makes any sense to you?
