FUEL GUAGE PROBLEM

There should be voltage at all sender wires. OEM mechanical regulator produced a pulse voltage through the gauge windings to fuel and temp senders. Oil sender also if there is an oil gauge. That would show 2.X to 3.x VDC on analog meter that averaged about 5 volts. A digital meter wont show more than rapidly changing numbers. "IVR4" suggests aftermarket solid state regulator. That is said to send increased voltage at switch on then settle back to a steady 5 VDC as needle reaches where it was headed.