I just put a new alternator in my 87 F-350 with a 460. Been about a month and the Amp guage was riding in the middle. Last couple of days, riding way over to the left (not charging much). Checked the connections to the alternator - seem tight. Put a charger on it and it's drawing the juice.
Maybe the alternator went bad - I guess it's possible but is there anything else I could or should be checking? Battery was new in September also.
Thanks

 

Check the belt tension. They can slip without any noise. Had this happen on my $200amp$ alt. when I put it in. If that's not it, run it down to NAPA or Pep boys and they can throw a meter on it before you pull it out.
Good luck.
1989 Centurion Classic Bronco

[link:groups.yahoo.com/group/centurionconversions/|https://www.ford-trucks.com/user_gallery/displaythumbnail.php?&photoid=3476&.jpg]<-< Centurion Club
1979 Bronco XLT
https://www.ford-trucks.com/user_gallery/displaythumbnail.php?&photoid=3923&.jpg

 

Check the voltage across battery terminals with the engine running-should be around 14 volts.If its 12 volts the alternator is not working properly.If you rev the engine while doing the test and the voltage goes way up past 14 volts then you have a bad regulator.


Hope this helps. RJMACK

 

Thanks for the replies - belt seems tight - I'll have them check the voltage. Is there any thing else that would cause the problem? Does the computer have anything to do with this? Aside from this, no other electrical issues that I know of but assuming it's the alternators, it seems that everyone says that the aftermarket units aren't reliable but if so, wouldn't Discount Auto, Auto Zone, etc. get tired of replacing and checking them and put pressure on the manufacturer?
In my business, we get rid of problem suppliers.