Quote Originally Posted by Gilbert Pierce View Post
Thinking more about your issue: If you are using the JPI and Piper gage on the same sender I would disconnect the Piper gage and see what happens on the JPI system an likewise the use Piper gage only.
The Piper fuel gage system is current driven. The gage is basically a Wheatstone bridge that measures current. The sender changes the current flowing thru one leg. The gage is an amp meter calibrated in gallons. I don’t know what the JPI uses but being solid state I suspect it is looking for voltage signal.
I think the JPI and Piper system are not playing well together.
JPI does not use voltage, its current driven as well and you use the resistance readings to "calibrate" the gauge as you fill the tanks. I will drain the tanks and go through the calibration again after I verify the gauges separately.

I think the best bet for me is to one day in the near future install the 25 gallon tanks with sight gauges and not worry about the electronic readings other than fuel flow and total burned.