I checked what I have leading to the ignition sensor and didn't get a current with the ignition on or off.. not sure if I should have

bingo

it wont start up without an ignition voltage. Try joining the power and ign lines (NOT THE POWER AND GROUND!!!) into the riocar. it should start up in this fashion.
You might prefer to install a temporary switch for the ign lead if the current lead is faulty.

ps. Think carefully about which wires you are joining, letting smoke out of the player is BAD.