SV-EMS-220 fault in a Harmony Evektor

[SamPrentice]

I am requesting some assistance with fault finding to a SkyView system installed into a sportstar LSA aircraft and the SV-EMS-220 engine Thermocouple unit that the EGT probes are wired to.

The system has a SV-EMS-220 Thermocouple sensor unit installed for all the engine monitoring parameters required for the sky view system.

The airframe is fitted with 4 EGT harnesses. They are of the green type insulation, unshielded and stranded core wiring. They are a complete, 1 piece, from the probe tip to the pins that go into the 25 pin D-type adapter on the Thermocouple unit.

What we were experiencing is that number 1 and no 4 EGT probes were indicating red X with no numerical indication. We managed to source 2 new harnesses of identical nature. No 4 EGT indicated correctly immediately however no 1 EGT still gave either a red X or erroneous readings of - 200 to 300 degrees when at ambient. After engine runs were done no 4 became erratic aswell.

I have swopped over harnesses to eliminate the possibility of a faulty new harness. I have swopped over with an existing working fitted harness previously installed and no difference. I have removed all the pins and fitted them physically to the Thermocouple unit sockets to eliminate mating issues and the actual connector seating correctly.
I have also cleaned both connectors with electrical cleaner but still no change.

We have managed to swop over a loaner SV-EMS-220 from a Sportstar and when we connected the unit we got 4 red X indications for the EGT temps. I am not sure if there is any configuration settings or any options that one may change in the SkyView system to set these units up.
I am reluctant to go any further with this issue before I receive some sort of guidance from Dynon. To me it looks like the actual Thermocouple unit is faulty.

 

[Dynon]

Something isn't adding up here, we agree. A few thoughts:

Values that are way out of line with any real temperature are often indicative of wires that aren't actually connected to the SV-EMS-220 at the right pins (or are broken, perhaps). If you disconnect the probe and connect the two sides of one EGT wire together you should see something close to ambient. That will let you test everything up to that 25 pin connector. Additionally, a sensor that is correct when the engine isn't running but is erratic when it is strongly points to an intermittent connection somewhere.

 

[SamPrentice]

Thanks very much for the information.
The suggestion to disconnect the probe and join the two wires together to show a close to ambient temperature, is not possible, due to the fact that the harness is manufactured as a single piece. I did mention this in the previous correspondence .
A working EGT probe was swopped over onto No 4 EGT line with no difference in indication.
Perhaps the simplest thing would be to purchase a SVS-EMS-220 from Dynon and if it doesn’t solve the problem we ship it back? what are the warranty and returns policies?

 

[Dynon]

It sounds like those aren't our EGT probes, or our harness. Given that, I'd be suspicious that the EGT probes aren't connected to the correct pins in the D25 harness. Some of the behavior you're experiencing is consistent with either disconnected, mis-wired, or intermittently-connected probes. From what you're describing, a this does not sound like a problem with the EMS module.

We don't have a return policy that covers the testing you're describing, but out technical support team may be able to help with testing your EMS or making other accommodations. Since you've tried an EMS from another aircraft and got similar / worse result, there's further evidence that something downstream from the EMS module itself is the issue.

For further help with this issue, please get in touch with our support team for more personalized support via either 425-402-0433 or support at dynonavionics dot com.

 

[SamPrentice]

Thank you for the swift reply and information. I will contact Support directly.

Best Regards