If the sending unit is new then check the wiring if that is good then your float could be stuck (unikley but possible) or your cluster has a short in it.
i believe you can take out the back seat and remove the sending unit from the top of the fuel tank (through the access plate). Then work the float manually by raising and lowering it. if the gas gauge doesn't change the reading then either the sending unit or the connector wiring is the problem.