The feedback carb has a computer that is connected to an 02 sensor, coolant temp sensor among other things... Without all of this the feedback carb will run full rich or full lean, I'm not sure which of the extremes it goes to with no connection.
The wire connects to a duty-cycle solenoid that fine tunes the mixture.
My 87 5th ave. still has the stock feedback carb on it and hasn't given any problems in the 5 years since I installed the Mopar Performance Ignition kit on it. Mancini Racing told me that it may run a little rich but not enough to hurt anything. I get good plug life and 19 MPG on the road. :gr_patrio