07-27-2022 | #1 |
Join Date: Nov 2016
Location: New Brunswick
Posts: 960
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What Would Cause an Alternator/Voltage Regulator to Fail Twice?
I had the lower fuel injector gaskets replaced recently. As it was not a job I wanted to undertake myself, I had a Corvette specialist dealer who still had some ZR1 knowledge do the job. On the way back home, about an hour into the drive, thr battery light came on and the voltage gauge dropped down. I'd had the alternator tested twice in the years before, and it had always passed with flying colours. The bearing had been a bit noisy, so that got replaced. But, as it was 30 years old, and the ZR-1 under hood area isn't friendly to things electronic, I wasn't too surprised. Took it back, they had the alternator rebuilt, and I was back on the road again. Survived the trip back this time, and all seemed ok.
Tonight, was on the way to the local car show, and the dash lights and Instrument panel flashed briefly. Weird, but all seemed ok and kept driving. About a minute later, I noticed the battery light was on and the gauge was showing low. Crap. Still running fine, but just off the battery. So, as it wasn't a problem before the plenum pull, and I'm not a huge believer in coincidences, I'm wondering what could they have done that would cause the voltage regulator to blow twice? And seeing as how the plenum was off for some extensive work, I'd guess it was something there. Any thoughts before I call the shop and start yelling?
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1990 ZR-1 # 996 "All Corvettes are red. The rest are mistakes." - John Heinricy |
07-27-2022 | #2 |
Join Date: Nov 2016
Location: New Brunswick
Posts: 960
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Re: What Would Cause an Alternator/Voltage Regulator to Fail Twice?
Made it home just fine and the car was running like a champ. Except for the charging part?
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1990 ZR-1 # 996 "All Corvettes are red. The rest are mistakes." - John Heinricy |
07-27-2022 | #3 |
Join Date: Jul 2020
Location: Nashville TN
Posts: 330
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Re: What Would Cause an Alternator/Voltage Regulator to Fail Twice?
Are you sure you have a good connection to the regulator? Particularly the voltage excitation wire?
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07-28-2022 | #4 | |
Join Date: Nov 2016
Location: New Brunswick
Posts: 960
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Re: What Would Cause an Alternator/Voltage Regulator to Fail Twice?
Quote:
What should I be checking on?
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1990 ZR-1 # 996 "All Corvettes are red. The rest are mistakes." - John Heinricy |
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07-28-2022 | #5 |
Join Date: Jul 2020
Location: Nashville TN
Posts: 330
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Re: What Would Cause an Alternator/Voltage Regulator to Fail Twice?
You should see a small wire that has 12 V with ignition on that goes to the regulator. You can disconnect the plug and check the pin in the harness. Also watch the voltmeter gauge does it show around 14 V when the car is running? If not then does wiggling the wire excitation wire plug change the behavior at all?
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07-28-2022 | #6 |
Join Date: Sep 2008
Location: Mullica Hill, New Jersey
Posts: 2,615
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Re: What Would Cause an Alternator/Voltage Regulator to Fail Twice?
Sounds like the original problem is still the problem.
If there are any looses connections starting at the battery and working out, that could cause a correctly functioning alternator to fail in charging the battery. The flash that you observed suggests some type of voltage interruption. Being as the problem did not exist before the work, i would carefully review every electrical connection and wire that would have been disturbed during the work as well as both battery cable connections. Let us know what you find or do not find. Marty |
07-28-2022 | #7 | |
Join Date: Nov 2016
Location: New Brunswick
Posts: 960
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Re: What Would Cause an Alternator/Voltage Regulator to Fail Twice?
Quote:
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1990 ZR-1 # 996 "All Corvettes are red. The rest are mistakes." - John Heinricy |
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07-28-2022 | #8 | |
Join Date: Nov 2016
Location: New Brunswick
Posts: 960
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Re: What Would Cause an Alternator/Voltage Regulator to Fail Twice?
Quote:
Not debating, but just asking. If there was a battery cable related issue, wouldn?t that effect how the car ran also? It feels like I could drive it forever, at least until the battery went dead. The first time it happened, it made the 30 mile drive home without any issue.
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1990 ZR-1 # 996 "All Corvettes are red. The rest are mistakes." - John Heinricy |
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07-28-2022 | #9 |
Join Date: Sep 2008
Location: Mullica Hill, New Jersey
Posts: 2,615
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Re: What Would Cause an Alternator/Voltage Regulator to Fail Twice?
I meant the initial electrical problem thought solved by the rebuild of the alternator.
An intermittent loose / poor connection prevents the current from the alternator to reach the battery. A review of what they removed or disturbed could solve the problem or eliminate the possibility Go get em! Marty |
07-29-2022 | #10 |
Join Date: Aug 2006
Location: McLean, VA
Posts: 3,727
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Re: What Would Cause an Alternator/Voltage Regulator to Fail Twice?
Just because an alternator was rebuilt won't guarantee that it's good. Internals used may be from questionable sources and fail prematurely.
I would have the alternator tested. When I had my alternator rebuilt by a local shop about 3-4 years ago, tech told me that he used S. Korean, Japanese or Taiwanese parts only (no US parts available). He lamented over Chinese sourced parts being unreliable. |
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