charging problem

[jasonw_2005]

so im driving my 93 GT when the volt gauge drops to low i take the alternator off and go have it tested at oreily their machine says its good so i put the alternator back on and take the whole car back to oreily and have it tested again. they say the battery is good but the alternator is not charging im like wtf ur machine just said the alternator is good so any ideas.

[garycrist]

Hook a voltage meter to the output of the alternator then to battery. This will tell you
the integrity of the alternator wire to the battery or the crummy connectors.
If the voltage is with-in a couple of tenths, hook up a suitable ground to the alternator case. If the voltage jumps, you have lost the ground!

[KungFuHamster]

great numbers! was it a dyno jet or mustang dyno?