Fuel guage reads zero, car won't run

[revron]

After disconnecting the battery do prevent a large voltage draw (?), and doing some repair to the wires under the drivers seat, the car would not run for more than 15 seconds. Everybody said fuel pumps, so I checked the pressure, and it was dropping off after 10-15 seconds. So I replaced both fuel pumps, both senders, regulator and filter in two operations. Same problem. That's when I noticed that the gauge read zero - and I know there was plenty of fuel in the tank (both sides). After further analysis I realized "the computer" was not sending the signal(s) to the in-tank sensors, so it thought the tank was empty, as the gauge indicated, then it shut the pumps off. I finally hot wired the fuel pumps by removing the relays, running wires from the #30 terminals (always hot) to switches under the dash, then back to the #87 terminals (direct to the fuel pumps). Now the car starts and runs normally when the switches are on. The gauge still reads zero and I only drive a couple of hundred miles before topping off the tank. Any ideas on why "the computer" stopped sending the signal to the in-tank sensors and how I can reset/fix it?? So far no codes on the icarscan.

[JFP in PA]

Whatever you did electrically, it sounds like the fuel system needs to be recalibrated, which requires draining both sides of the tank, refilling with a specific amount of fuel, then use of the PIWIS system to recalibrate the vehicle.