I bought a conversion kit from shift works for fuel and bat. on the fuel gauge, oil and temp in the clock space. The fuel gauge didn't work. I checked the sending unit and the wire that runs to it. There both good. I put the old gauge in and still nothing. With the key in run position it came up but when I started the engine it dropped back down. I ran a seperate ground to the instrument panel housing and still didn't work. Any idea what I'm missing?