I bench tested my 6’ long Vision Microsystems fuel probes yesterday. The connection wires are red black and white, which are +5v, ground, and signal, respectively. The output signal was 4Khz empty, and 2Khz when filled with avgas. A small quantity of aluminum chips came out when I drained the probes at the end of the test. The debris was presumably left over from the manufacturing process.

Tip: slosh your fuel probes with avgas before installing them.

-Adam Molny