RVDan
I love flying!
I have had my Skyview system flying for a couple of years. I recently had a problem with my fuel pressure readings that has plagued me for 2 months. The fuel pressure would read 5 to 5.2 PSI whether there was fuel pressure or not. This was intermittent. This is a particularly onerous failure in that this is a proper reading for the fuel pressure for a carbureted Lycoming engine. One could be (I was) lulled into thinking everything is OK until one day I noticed the fuel pressure before starting the engine was at 5PSI and the electric fuel pump wasn't on. I removed the transducer and started to check voltages at the transducer. I pulled the connector and verified 5VDC at the connector. Then I needed to check the voltages with the transducer plugged in. I made a test harness and set the circuit up. At first I saw the input power (5V) at 1.9V or so. Went to recheck that I had the pin outs correct then got 5.05 V. Hmmm. Then when I looked at the Skyview display, the fuel pressure was showing 5PSI. OK, so I went through this sort of exercise several different times (over a couple of weeks), and kept getting varying results.
When installing the system, I had spliced the wires that come made up to the sensor connector, to the wires that went to the EMS at about 6" from the sensor. I did this using the environmental Raychem solder spices. When checking them visually, they seemed sound and tugging on them made no difference. Reasoning that if the 5V power supply in the EMS was failing, other sensors would be a problem also, I decided to cut out the solder splices and remake those connections. When I did I got 5V at the sensor power input and everything is once again happy.
I dissected the solder splices. When I cut off the sealant and insulation, the wires fell apart on the power input wire. I found that the solder had been fully absorbed by the AWG16 wire premade to the connector and that little or none was in the AWG22 airframe wire running to the EMS. The insulation and sealant of these splices is quite stout to provide strain relief on these splices. It held the wires in contact. Apparently the splice was electrically conductive at first, but then broke down. In operation, the resistance of the splice was enough to drop the voltage to the sensor to around 1.9V and the sensor would output about the same which is roughly equal to 5PSI.
This is an interesting latent failure of the circuit that led to a misleading indication in the cockpit of an important parameter. No deficiency of Dynon's part, but something to be aware of.
When installing the system, I had spliced the wires that come made up to the sensor connector, to the wires that went to the EMS at about 6" from the sensor. I did this using the environmental Raychem solder spices. When checking them visually, they seemed sound and tugging on them made no difference. Reasoning that if the 5V power supply in the EMS was failing, other sensors would be a problem also, I decided to cut out the solder splices and remake those connections. When I did I got 5V at the sensor power input and everything is once again happy.
I dissected the solder splices. When I cut off the sealant and insulation, the wires fell apart on the power input wire. I found that the solder had been fully absorbed by the AWG16 wire premade to the connector and that little or none was in the AWG22 airframe wire running to the EMS. The insulation and sealant of these splices is quite stout to provide strain relief on these splices. It held the wires in contact. Apparently the splice was electrically conductive at first, but then broke down. In operation, the resistance of the splice was enough to drop the voltage to the sensor to around 1.9V and the sensor would output about the same which is roughly equal to 5PSI.
This is an interesting latent failure of the circuit that led to a misleading indication in the cockpit of an important parameter. No deficiency of Dynon's part, but something to be aware of.