D120 fuel gauge erratic readings

[blueflyer]

D120 fuel flow gauge reading erratic after 4 years of rock steady operation. I replaced the FT-60 but I still get same erratic readings. D120 EMS Pin 14 runs to the fuel flow gauge (FT-60 in this case). Pin 14 should supply 5 volts to FT-60, but I am reading a steady 4 volts coming from Pin 14. What can be done about that?

The power and ground wires to the FT-60 were also checked and found to be good.

 

[Majorpayne317641]

You can send it to Dynon for a flat rate repair. They are very expeditious it just costs $850 for the service. Make sure that’s what is wrong. While you are at it tell them you want your screen refreshed it will look much better when you get it back!

 

[blueflyer]

I guess I could do that, but I was hoping for another avenue to check/repair.

 

[Majorpayne317641]

If it is anything to do with the internals of the unit then it really would be a Dynon job. You can check for proper ground/single source ground for all your electronics. Check for good wires and no chaffing. Check your battery output. Finally you can get resistors to build your own 5v source and see if you can duplicate the problem with a known good 5v source. Double check that your sensor is in fact good by using it on another engine or using another sensor on your engine.

 

[JonJay]

JPI has a simple test circuit that you plug in/replace the sender. There is a troubleshooting guide that assists in isolating where the issue is…. Ie wiring, instrument, or transducer through your volt meter measuring various pins on the tester.
Perhaps Dynon has such a tester or can guide you further on how to isolate the system components.

 

[blueflyer]

thats interesting. I will look into that tester. I just cant bring myself to send in a D120 for a $900 repair. I have an email in to Dynon tech support. Hopefully they will have something to help.

 

[blueflyer]

just to close this thread, I think I found the issue. After doing some work under the cowl, I forgot to re-secure the fuel line entering the red cube. After re-securing this fuel line at the inlet side of the red cube with its adel clamp, the erratic behavior went away. I think it was vibrating without the clamp installed and producing bubbles and the erratic readings. Thats my best guess at the moment anyway. I flew after re-installing the adel clamp and the fuel flow was rock solid.