A quick and easy to use method when deterring a charging problem is to watch/notice the "battery" light. Ignition key to the #2 position (KOEO-key on engine off) battery light should be lit.

If it is not lit then ground the blue wire at the alternator, light should come on. If it lights up then you will need an Alternator (diode is open)

If the light is dimly lit while driving then you may get away with a replacement regulator. On your engine my information shows it is an integral part of the alternator, if so look at the armature when the reg is removed. If it is grooved replace the entire assembly.