zx12argh, The ZX12's fuel sensor reads 126ohms on empty & 8-10ohms on full, which should be close to perfect for the dash which requires a 0 ohm reading on full & 100 ohm reading on empty.( you may want to bend the float arm down slightly so it doesn't read empty too early)
Check your wiring first, then you may want to check that the float sensor is giving the correct reading.