Pontiac Repair: Firebird 400 charging issues, wire alternator, body cars

Question
QUESTION: I have just about finished a 400 resto and am having charging issues.  I have new battery and alternator which test good, checked wires from started to battery and alternator, all good.  When running, I only get 11.?? at the battery and continue to run it down.  Any thoughts?
Thanks,
Aaron

ANSWER: Hi Aaron:

what year is this car and is the alternator you have on the engine the original one for the car? did this car come with that size engine? or was it an engine swap as well. Most of the "newer" F/body cars with a 400 had alternators that had the voltage regulator internal to the alternator. So they are basically just a 1 or 2 wire alternator The big red wire on the back of it is hooked to battery volatge either VIA the starter or directly to the battery and it should have battery volatge all the time. the small plug that plugs into the side of it shoul have 1 or 2 wires. they should have battery volatge on them with the key in the run position. One may be dimmer then the other with a test light because it runs the "batt" light on the dash it's a pretty simple system make sure you don't have any blow fuses if your missing volatge on any of the wires or a burnt out fuseable link for the Big wire on the back of the alternator.


---------- FOLLOW-UP ----------

QUESTION: Thanks so much for the response.  The car is a 67.  Yes it came with a 400 and no, the alternator is a new (actually the 3rd new) single wire alternator for this engine.  my first thought was the alternator was bad or going so, I swapt them out.  Then changed the battery, then checked or replaced fuses and wires directly associated with the battery, starter and alternator.  This alternator hooks directly to the battery.  Nothing goes back to the guage cluster.  Any thoughts?

Answer
The extra wire on the side of the alternator needs to have ignition power as stated above. If it does then it should charge. That is as long as the battery feed cable has power on it as well. Make sure there is no excessive resistance in that cable un hook the battery and check for the resiatnce with the battery un hooked.