Chip,
>From your description, you have a capacitive fluid level gauge. These
are comonly used in industrial settings and also in aviation. The
capacitance between the two rods varies with the liquid level. The tube
dampens any sloshing. These things are typically smack dab in the
middle of the tank.
Capacitors have reactive impedance- they only effect the circuit when
voltage and/or current flow is changing and have no effect on straight
DC current. Auto fuel gauges use variable resistance in a DC circuit.
If a standard gauge is connected to your fuel cell, it should see it as
an open circuit.
You need to chop (square wave) or invert (sinusoidal AC) the signal
from the fuel gauge to the sender and then be able to measure any
change. If you have one of those fancy digital multimeters that measure
capacitance you could plot capacitance vs. fuel level and figure out a
circuit that converts this to curren flow for a Morgan gauge.
Personally, as a mechanical engineer, I would keep the stick.
Regards,
Bill Eastman
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