Car will not stay running after a jump. on 1991 Pontiac Sunbird

Replaced alternator and battery. Both still test good. Car will run on charged battery when it dies the car stops running. It will also run when jumper cables are connected when you disconnect them it dies

Asked by for the 1991 Pontiac Sunbird
On the back of the alternator there's a power wire make sure you have power there if not ,you got burnt out fuse able links..
Other than that you have 14.0 volts at battery when running , if u don't which I know you don't ,u have defective new alternator.