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Discussion Starter · #1 ·
I replaced my alternator about a week ago. The alternator was seized it shredded the accesory belt before i figured it out. I bought a new AC delco off of Rock Auto. It was working fine the only I noticed was it didnt show it charging right away on the Atari gauges after a second it would show it charging. Now all of a sudden I get the Alternator display on my DIC. The battery at rest is ~12VDC too low I know but with the car running the battery voltage dips to 11.5. I did not replace the tensioner car has 87xxx miles. Obviously the alternator is not charging but this is brand new any ideas?
 

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Happen to know the part number of the replacement alternator? Brand new as in not remanufactured? Presuming both the alternator and battery connections were checked, what about the battery ground bolt? Pontiac G8 Forum. If the charging issues occured after alternator replacement, then the ground bolt is probably a moot thought. Presuming the correct size accessory belt was installed, is it snug against the various pulleys? If you think the alternator is defective, someone may be able to bench test it for free.
 

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You can clearly see if the alternator is moving with the hood open and car running.

Verify if actually brand new vs reman
 

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Hindsight being 20-20, in the past when I suspected an alternator, I would have a new one on hand, then remove the old one and bring it in to be bench tested prior to installing the new one. Kind of crummy to use them without buying a part from them, but it beats replacing a good part with a good part, and not fixing the issue, and it only takes a few minutes of their day.
 

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Just checked their website. Currently, the re-manufactured alternator (AcDelco 3343005) is over $25 more than a brand new unit (AcDelco 92191127) before the $7 manufacturer rebate.
 

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Discussion Starter · #6 ·
AcDelco 92191127) Is what I bought I will look into this thanks or all the help.
 

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Mentioned the accessory belt since it was replaced due to being shredded after the alternator seized. A semi-loose serpentine belt can cause it to glide/slide over the pulleys versus truly gripping and turning. To some extent, the belt tensioner can remove the slack and hold/maintain tension. However, the tensioner may not adequately compensate for slack if the spring is too worn or the belt is simply too big. At 87,000 miles would think the tensioner still has quite a bit of life left. Just a thought. :geek:
 

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Discussion Starter · #8 ·
So I did some quick measurements Alternator purchased from Rockauto (ac delco) is new ,made by Misubishi Electric pn 9219127. With ignition off battery has ~12 v on it. Line going to alternator is also ~12. I turned on the headlights battery goes to 11.5 volts same as the line going to alternator. My voltmeter says alternator is grounded to block .2 ohms. When I start car battery goes to 11.5 also line going to alternator is 11.5 volts. Within a few seconds alternator light comes on in DIC digital display also in car says battery has 11.5 volts on it. Alternator worked for a week ran car about three times on short trips. Should i get alternator tested ? All the grounds look good.
 

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For clarity, check the underside of the battery ground bolt referenced above. Brand/age of battery? Has it been tested? If I recall correctly, the "alternator" message indicates a problem with the charging system and does not specifically implicate the alternator. May want to consider having the battery tested. Locally, Firestone seems to have the more accurate battery testing device. If the battery tests well and both battery and alternator connections are fine, then have the alternator tested. Easier to do the fromer versus the latter.
 

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Discussion Starter · #10 ·
Well battery tested out fine stupid me broke the battery ground bolt it was seized so I am going to drill and tap a new hole for it.See how that goes if no improvement I will get the alternator tested. Thanks for all the help Pony Man
 

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The bolt was seized as in rusted on the underside? Some places like Auto Zone and OReily's can "test" the alternator while it's still on the vehicle. However, covid-19 precautions may have changed their protocol a bit.
 

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OP, for your awareness, the charging system is not old school. Here is a description. Alternator does not have internal regulator, it's managed by the BCM.
 

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That's the positive bolt and if the nut wasn't adequately tightened it could have arced enough to melt the plastic. At any rate, was the nut snug prior to removing the wire? Were you able to resolve the broken battery ground bolt issue? Are you going to have the alternator bench tested?
 

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Discussion Starter · #16 · (Edited)
. Autozone said that they cannot bench test that alternator not supported. As far as the broken battery ground I drilled a new hole nearby the old one and tapped it. I will recheck connections that go to the alternator sand them to clean them up. Its possible it wasnt tightend correctly kind of pain in the ass to get to it.
 

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Can try calling Advanced Auto if they're local or some of other places doing alternator testing.
 
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A semi-lose positive connection may have been the issue all along since the alternator worked fine for nearly a week.
 
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