6865coronet

I tried to install a CD player in my car i took the constant voltage from the old Am FM and put in on my cd player then took the start voltage and hooked it up to the CD player just like i do in every stereo i install. Once i tried to start the car it wont start it just goes DU DU DU..... so i disconnected the CD player and i jump started the car and it started no problem i let it run for 6 minutes or so and turned it off and now its doing the du du du.. every time i try to start it up? Anyone have any clue what may be wrong. All the fuses are good everything works but the engine wont start.