Alternator trouble

[soundcontrol]

My car stopped charging a few days ago, is there any measurement I can do on the alternator or voltage regulator to figure out the problem? Got 12,7 V on the battery now (after charging it all night) and running the engine dosen't raise the voltage over the battery at all, so nothing comes out of the alternator, battery is OK, and the belt is fine.

[DocMel]

Ensure your voltage regulator is WELL grounded on the bulkhead wall. The four mounting screws into the bulk head that mount the reg can get corroded , loose over the years.  I actually but a small ground strap in addition to the old mounting screws (which was my charging prob)

Also check the plug in connector.  The get really corroded or worn, and depending what type of air cleaner yo have, the base can bang up against the connector it during removal/installation, and can loosen/wear out the connector

[Chryco Psycho]

The reg is a $12 part , I would try that first , the alts are typically reliable or might need a set of brushes .
 You need 12v through the blue wire into the alt field & reg , if you make a jumper & ground the field on the terminal the green wire goes to it should charge max output so you can test the alt that way before spending any money

[HP_Cuda]

Lots of parts places will take your alternator and test it for you, all you have to do is pull it off which isn't that hard.

I just replaced an alternator and regulator recently.

[soundcontrol]

Thanks for the tips guys, I will check all those points, have a week of work out of town now so I wont get to the car until next weekend, but I will post the results then.

[dodj]

Got 12,7 V on the battery now (after charging it all night)

Use another battery. 
After charging all night and having no load on the battery, it should be over 13v. It may be pooched.

[Strawdawg]

12.7v is about what a fully charged battery settles to a few minutes after coming off the charger

[LAA66]

 After sitting a couple months mine would not charge either. I jiggled the related wires and regulator, and it began work again. Must have been the moisture in the air over time caused corrosion somewhere in the circuit. 

[soundcontrol]

Fixed! It was the volage regulator. I borrowed one from a friend and tested. 15 bucks in the US, $65 in Sweden... 

[soundcontrol]

I'll take that back... Driving the car today, it was charging like crazy, way more than normal, supercharger... Then suddenly it stopped, then it started charging again, but this time only a little bit, needle moves a little bit when I rev the engine but not that much, if I have the lights on its more on the D side. Very stange. Can't measure the voltage on the battery now since its pouring rain here. I need to check the connections again, did that before I changed the regulator, with no results, and I also checked that the regulator had good ground in the firewall. Could be a battery problem also.

[soundcontrol]

No charge at all today, dead. Can a bad alternator destroy the new voltage regulator?

[swede-cuda]

  try with a god battery,see if it gets better.  no Swedish flag in the iconlist, so ill wave this one.

[soundcontrol]

try with a god battery,see if it gets better.  no Swedish flag in the iconlist, so ill wave this one.

Good flag! yeah, gonna try to borrow another battery tomorrow and see, could be a bad cell or so. It actually took a long time to charge it with a batterycharger the first time it stopped charging. But I thought if the alternator actually worked, the volts at the battery terminal would be higher than it is, 12.1 now running, 12.2 not running.

[dodj]

I'm thinking the voltage regulator ground may be an issue. Make sure it is clean. I use a star washer to make sure I have a good ground.

[Chryco Psycho]

sounds like a problem with the battery , could damage the alt charging for long at max output