Mike, Three things...
1. What kind of truck do you have?
2. You should check your wires to ensure that they are not grounding out. I would recommend running new wires.
Next, come off your fuse box with a hot wire (one that is keyed) to the IGN side of the gauge Then, take the wire from your sending unit and connect it to the other side of the gauge SENDER. If you get these turned around you will burn up your sending unit. To go a bit further, i would make sure your tank is grounded well to the frame.
3. When you installed the new gauge in the housing check to see if it's touching the housing and grounding out (HOT LEAD). This could be why it's shorting out and smokes.
Jeremy
