UMA Tach sensor doesn't work with Garmin G3X help!!!

[AirbusPilot]

Dear Folks,

I am almost finishing G3X install in my plane but tach sensor from uma (T1A9) is not working and always reading 0, I have checked wire many times, only strange thing is that garmin manual connect white/orange wire to pin 58 which is +10 volts and not 12 as UMA requested, I have connected white/blue to 57 and white to 17, any help please

Cheers,

PD: second problem but minor is CHT3 is showing 85 degree, everything else shows 72, when I start the engine CHT3 got a X, everything else works (except rpm)

[Radomir]

try feeding the sensor from the battery.. that'd give you 12V that would rule out voltage as source of the problem..

[g3xpert]

Hello Fernando,

The UMA T1A9 sensor requires between 5 and 24 volts according to the manufacturer's specification sheet, so either the +10V or +12V transducer power pin should be fine. Assuming you've checked the connections to the GSU 73, I would carefully check the wire colors on the sensor against the instruction sheet that came with it. UMA has been known in the past to use different wire color codes at different times, so you should always use the latest documentation that comes with your sensor.

As for your thermocouple problem, I suggest looking for wiring problems between the CHT probe and the GSU 73, including open circuits and reversed wires. You can also try swapping your #1 and #3 CHT thermocouples to see if the problem follows the sensor or the wiring.

- Matt

[AirbusPilot]

Originally Posted by g3xpert

Hello Fernando,

The UMA T1A9 sensor requires between 5 and 24 volts according to the manufacturer's specification sheet, so either the +10V or +12V transducer power pin should be fine. Assuming you've checked the connections to the GSU 73, I would carefully check the wire colors on the sensor against the instruction sheet that came with it. UMA has been known in the past to use different wire color codes at different times, so you should always use the latest documentation that comes with your sensor.

As for your thermocouple problem, I suggest looking for wiring problems between the CHT probe and the GSU 73, including open circuits and reversed wires. You can also try swapping your #1 and #3 CHT thermocouples to see if the problem follows the sensor or the wiring.

- Matt

Hi Matt,

From UMA

White/blue ground, I have connected to 57
White/orange +12, I have connected to 58
White signal, I have connected to 17

I could try to swap between 57 to 17, can I burn something???

[AirbusPilot]

I just change wire side from CHT 3 and is working OK, now I just have to fixs rpms

[AirbusPilot]

I checked tach sensor wires for continuity with a tester, there is no connection between the 3 wires with each other or with plane ground, but white/blue wire is connected with tach wire shield, is that normal, G3X said you should ground shield at GSU connector but shield is already grounded by white/blue wire, I think maybe sensor is bad

[AirbusPilot]

Ok, after checking everything many many times and reading the manual till I know tach wires color and pin of memory, I was looking for info on the Internet, then I found MGL sensor installation manual, and that manual has only 14 pages, not 200 like garmin, but it was clear, I attached sensor in the wrong hole at magneto

Thanks MGL for write a great and very clear manual!!!!!

[Brantel]

Same thing happened to a buddy of mine a few years ago when he was installing an AFS EMS. Glad you got it sorted out!

[g3xpert]

Fernando,

Glad you got your RPM input working. You can also double-check with the manufacturer's instructions to verify the correct installation. We pride ourselves on the completeness and detail of our manuals, but we're always happy to get customer feedback to make them even better. I'll make sure to ask our technical publications department if they can do anything to make the instructions more clear in this area.

thanks,
- Matt

[AirbusPilot]

Originally Posted by g3xpert

Fernando,

Glad you got your RPM input working. You can also double-check with the manufacturer's instructions to verify the correct installation. We pride ourselves on the completeness and detail of our manuals, but we're always happy to get customer feedback to make them even better. I'll make sure to ask our technical publications department if they can do anything to make the instructions more clear in this area.

thanks,
- Matt

Hi Matt,

I think Garmin manual is very good and complete, but MGL have pictures that make the manual "fool proof"

Thanks for help!!!