Capacitance Fuel Voltage Issues - no voltage difference on Calibration

[RV Triumph1974]

Having issues getting the fuel level calibration for the capacitance (Vans) to show up on the EMS. I get the X message at the individual fuel widget level after doing the calibration process. I am getting the same voltage read out during the calibration process for each 2 gal increments on the screen while doing the calibration, however I know I am getting voltage being sent to the Dynon as I confirmed that with a DC volt meter, and after refueling I get the "fuel calibration message" that gals of fuel remaining from the red cube fuel flow used calculation is different from the actual capacitance fuel sensor gage total readings

Anyone else experienced this issue, and have suggestions?

Thanks!

 

[swatson999]

What C2V converter are you using?

 

[RV Triumph1974]

The original Vans

 

[swatson999]

I never was able to get those to work well...they used only a tiny portion of the available 0-5V, and calibration was sketchy.

I am getting the same voltage read out during the calibration process for each 2 gal increments on the screen while doing the calibration

This was what I saw, as well. Although the data *are* changing, it's so far down in the fractions of a volt that it doesn't show on the display. I tried several times to get a decent calibration, and finally gave up.

I switched to the Princeton 2-point converters and they have worked great for nearly 13 years now. You might consider that. Although, others have reported success with the Van's converters.

 

[airguy]

Another vote for the Princeton converters, they worked much better for me.

 

[jakej]

Likewise-however if you have an EFIS/EMS display it is easier to just use the Red Avionics (aka Princeton) 1 - point setup - (set empty only) & then do the calibration via the EFIS/EMS screen = simple

 

[RV Triumph1974]

Thanks for sharing the info! Where are you all mounting the Red Avionics unit? - it looks like it may have to be mounting inside the floor and not in the space under the wing root fairing as it looks fairly large relative to the Vans sender.

I did run across this today....https://www.youtube.com/watch?v=nNRRy1yCpHc
I may try and see what will happen by doing what some of the BMW motor bike guys are trying when they have issue with their capacitance fuel gauges...no idea if it will work, but will let everyone know once I try it out.

 

[swatson999]

Or, you could just fix it right. Plenty of people have capacitive senders and I don't recall anyone ever doing something like this to "fix" the passive components of the system.