Hello again.
88 Pontiac 6000 2.5 4Tech 127K miles.Friday, the alternator light came on. Wife stopped by trusted mechanic who fiddles under hood and asks if light went out... no... then it's the alternator. She tells him I can do that and continues home.
I pick up used one at a quality, respected recycler and slap it in there. Car won't start on it's own but jump starts... but would not continue to run for long. Charge battery a little from another car and repeat experiment and it jumps but stalls again in 5 minutes. I assume battery is low as she drove it home without alternator and go to Auto Zone (last night) where battery was purchased to be safe and get a 40 minute charge... guy says it's good and not low and doesn't need a charge. Heh. Bring it home and put it in another car and it's dead. It's late so I quit for the day.
This AM I put another battery in Pontiac and it cranks but won't start (always an easy starting car) until I try it with pedal to floor as if flooded and it started and after rumbling a moment or five it runs fine.
I went to another parts store (with substitute battery in it and Auto Zone's in the trunk) and asked them to check charging system and they say it's charging fine but the battery in trunk is too low.
Went back to Auto Zone and he checks it and it shows 50A steady at idle... but when he says to tach it a ways he shows me that digital readout jumps around wildly from maybe 50A down to maybe 30A up to maybe 45A down to maybe
11A up to maybe 20A and down to maybe 9A and back up to maybe 40A again and so on. Says this indicates the alternator is bad even though the light is no longer on. Checks his battery in trunk again and says it's good but needs pro-rated and warranted anyhow. Huh? Why? Because it might be good but not good enough. Huh? What the heck, I figure,... it's a good 875 CCA Dual Terminal 8 year battery and for not many bucks I can get a new one, so I did it.Should this Alternator show amperage fluctuating wildly?
Should I return the alternator to the Parts recycler?
Is the Auto Zone guy full of crap, trying to cash in, or diagnosing correctly?
Why can't anything be simple?
Thanks for any input.