I believe that your Westburg probes actually act like they are resistive probes. You need to figure out exactly what probes you have and how they work. Unhook the probes from the EFIS and make them work with a volt-Ohm meter to verify that they do work.

Do they put out a 0-5 Volt DC signal with fuel or a 40-240 ohm signal?

If they are 40-240 Ohm you cannot connect them to a separate fuel gauge and the EFIS, the EFIS should be configured for float fuel sensors.