Alternator going bad?
Thread Starter
Melting Slicks
Joined: Aug 2008
Posts: 2,561
Likes: 1
From: Oakland Ca
St. Jude Donor '09
Alternator going bad?
Hey All,
For a few weeks now I get an intermittent "Charging System Fault" message when I first start the car in the morning and sometimes on my way home from work. It would go away within a few minutes and go back to normal. Every time the "Charging System Fault" message comes on I noticed that the volt gauge drops down to like 11v, normally it's around 13v or more. The other day on my way home from work the "Charging System Fault" message came on longer this time and volts went down to 10v. It went away but then I noticed the gauge went up to almost 15v! Then the "Check Gauge" light goes on and then I got the "High Voltage" message! Yikes!!
I then put my windows up trying to use voltage draw. This lowered the volt gauge back down to 13v and was back to normal for the rest of the drive home.
So my question to this great and knowledgeable group is do I need a new Alternator?? Seems like a regulator is bad?? I did check for loose and bad connections as well as checked my belts. All looked good and clean.
Any advise??
Thanks in advance.
For a few weeks now I get an intermittent "Charging System Fault" message when I first start the car in the morning and sometimes on my way home from work. It would go away within a few minutes and go back to normal. Every time the "Charging System Fault" message comes on I noticed that the volt gauge drops down to like 11v, normally it's around 13v or more. The other day on my way home from work the "Charging System Fault" message came on longer this time and volts went down to 10v. It went away but then I noticed the gauge went up to almost 15v! Then the "Check Gauge" light goes on and then I got the "High Voltage" message! Yikes!!
I then put my windows up trying to use voltage draw. This lowered the volt gauge back down to 13v and was back to normal for the rest of the drive home.So my question to this great and knowledgeable group is do I need a new Alternator?? Seems like a regulator is bad?? I did check for loose and bad connections as well as checked my belts. All looked good and clean.
Any advise??
Thanks in advance.
Melting Slicks
Joined: Aug 2000
Posts: 2,146
Likes: 2
From: Florida
i hope you get a good answer since the exact same thing keeps happening to me.
i should get it fixed but its been about a year since it started and its not getting worse.
you hate to drive into the dealership with your pants down hoping they dont ask for a pint of blood.
i know its risky but when it fails completely, then i'll know exactly what was wrong.
thank god for AAA.
i should get it fixed but its been about a year since it started and its not getting worse.
you hate to drive into the dealership with your pants down hoping they dont ask for a pint of blood.
i know its risky but when it fails completely, then i'll know exactly what was wrong.
thank god for AAA.
5th Gear
Joined: Jun 2011
Posts: 5
Likes: 0
From: Indiana
Am interested in this sort of thing, but have no direct experience with this control system or physical hardware. That is, I presume it's a system that actively manipulates the alternator field and not one that has a "dumb" alternator.
My list of usual suspects would be, roughly in this order:
1 Alternator voltage feedback circuit (would mean a new alternator)
2 PCM driver (would likely mean a new PCM)
3 Intermittent or loose connection between the alternator voltage feedback and the PCM, But that sounds like kind of a long shot for this.
I'd rule out the connection between the alternator and battery since your vehicle voltage goes up sometimes.
Being curious, I looked around a little and found this thread, which may help:
Earlier thread:
http://forums.corvetteforum.com/c5-t...eed-ideas.html
My list of usual suspects would be, roughly in this order:
1 Alternator voltage feedback circuit (would mean a new alternator)
2 PCM driver (would likely mean a new PCM)
3 Intermittent or loose connection between the alternator voltage feedback and the PCM, But that sounds like kind of a long shot for this.
I'd rule out the connection between the alternator and battery since your vehicle voltage goes up sometimes.
Being curious, I looked around a little and found this thread, which may help:
Earlier thread:
http://forums.corvetteforum.com/c5-t...eed-ideas.html
Thread Starter
Melting Slicks
Joined: Aug 2008
Posts: 2,561
Likes: 1
From: Oakland Ca
St. Jude Donor '09
Am interested in this sort of thing, but have no direct experience with this control system or physical hardware. That is, I presume it's a system that actively manipulates the alternator field and not one that has a "dumb" alternator.
My list of usual suspects would be, roughly in this order:
1 Alternator voltage feedback circuit (would mean a new alternator)
2 PCM driver (would likely mean a new PCM)
3 Intermittent or loose connection between the alternator voltage feedback and the PCM, But that sounds like kind of a long shot for this.
I'd rule out the connection between the alternator and battery since your vehicle voltage goes up sometimes.
Being curious, I looked around a little and found this thread, which may help:
Earlier thread:
http://forums.corvetteforum.com/c5-t...eed-ideas.html
My list of usual suspects would be, roughly in this order:
1 Alternator voltage feedback circuit (would mean a new alternator)
2 PCM driver (would likely mean a new PCM)
3 Intermittent or loose connection between the alternator voltage feedback and the PCM, But that sounds like kind of a long shot for this.
I'd rule out the connection between the alternator and battery since your vehicle voltage goes up sometimes.
Being curious, I looked around a little and found this thread, which may help:
Earlier thread:
http://forums.corvetteforum.com/c5-t...eed-ideas.html
Thanks for the advise guys!
The link was helpful, thanks 50N40W
I ended up ordering a re manufactured AC Delco alternator for about $261 including core charge and shipping. It arrived yesterday.
Thread Starter
Melting Slicks
Joined: Aug 2008
Posts: 2,561
Likes: 1
From: Oakland Ca
St. Jude Donor '09
i hope you get a good answer since the exact same thing keeps happening to me.
i should get it fixed but its been about a year since it started and its not getting worse.
you hate to drive into the dealership with your pants down hoping they dont ask for a pint of blood.
i know its risky but when it fails completely, then i'll know exactly what was wrong.
thank god for AAA.
i should get it fixed but its been about a year since it started and its not getting worse.
you hate to drive into the dealership with your pants down hoping they dont ask for a pint of blood.
i know its risky but when it fails completely, then i'll know exactly what was wrong.
thank god for AAA.
AAA to the rescue!!
Race Director
Joined: Jul 2007
Posts: 18,681
Likes: 47
From: Reno is so close to Hell you can see Sparks , State Of Confusion
St. Jude Donor '12-'13-'14
I had the same issue a few years ago when I started the car, In my case it was the battery, At start-up voltage was low after sitting for a while and I got the message, Replaced the battery and haven't had an issue.
Mr.Bill
Mr.Bill
Intermediate
Joined: Jun 2011
Posts: 47
Likes: 0
From: DFW Texas
If you own a volt meter start the vehicle and hold the terminal tips to the battery posts respectively. With the vehicle running you should see around 14.2v across the battery, turn on all lights and A/C or heat and it should drop to no less than 13v, have a second person rev the engine to around 2k and volts should go up to 14v.
This is an old school way of doing things but can be dangerous(perform at your our risk) Not 100% sure if this works for Vette's but most vehicles once the vehicle is started and running you can disconnect the positive battery cable from the battery(taking the neg. will break ground engine will die.) If the vehicle stays running it's battery; if it dies then it's most likely the alt.
Also as someone mentioned earlier it's prob a faulty voltage regulator however most are built internally to the alternator housing so changing just that is pretty much not possible unless you know how to rebiuld alternators.
Brandon
This is an old school way of doing things but can be dangerous(perform at your our risk) Not 100% sure if this works for Vette's but most vehicles once the vehicle is started and running you can disconnect the positive battery cable from the battery(taking the neg. will break ground engine will die.) If the vehicle stays running it's battery; if it dies then it's most likely the alt.
Also as someone mentioned earlier it's prob a faulty voltage regulator however most are built internally to the alternator housing so changing just that is pretty much not possible unless you know how to rebiuld alternators.
Brandon
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Thread Starter
Melting Slicks
Joined: Aug 2008
Posts: 2,561
Likes: 1
From: Oakland Ca
St. Jude Donor '09
Race Director
Joined: Jul 2007
Posts: 18,681
Likes: 47
From: Reno is so close to Hell you can see Sparks , State Of Confusion
St. Jude Donor '12-'13-'14
5th Gear
Joined: Jun 2011
Posts: 5
Likes: 0
From: Indiana
It depends on how the software/hardware was done. I don't think you should have seen 15 volts if it was just the battery, but I don't really know.
Instructor
Joined: Aug 2010
Posts: 170
Likes: 5
Must be summer me too........
I have a blown 08 Z51 and have had NO issues until a 5 mile drive last night. Car was getting hot (dual electric fans clearly quit working) and then came a host of check anti lock brakes, check this/that.
Stopped car and sure enough NO electrical power and volt gauge was down to 8 volts.
Battery is at Auto-zone charging right now and appears to still be good OR at least taking charge without showing to be bad.
Once re installed back to AZ for them to check and see if alternator is bad?
Questions: (is this common problem I heard not?)
1. If so........anyone know if warranty (2008) may still cover doubt it with supercharge installed. Past the 36 month but did not know if 100k
2. I have changed many alternators on past cars ANY tricks to doing so with our cars?
3. Biggest concern would be to get tension right with the serpentine belt running all front facing components
4. ANY suggested remans to buy OR all about the same. Autozone can have one for me today for about $220.
5. Do I have to get codes cleared/re set since battery has now been removed?
6. Are presets of any of the car from radio to personal settings saved by chance?
Thanks for any feedback?
David/TOO freaking HOT Dallas
Stopped car and sure enough NO electrical power and volt gauge was down to 8 volts.
Battery is at Auto-zone charging right now and appears to still be good OR at least taking charge without showing to be bad.
Once re installed back to AZ for them to check and see if alternator is bad?
Questions: (is this common problem I heard not?)
1. If so........anyone know if warranty (2008) may still cover doubt it with supercharge installed. Past the 36 month but did not know if 100k
2. I have changed many alternators on past cars ANY tricks to doing so with our cars?
3. Biggest concern would be to get tension right with the serpentine belt running all front facing components
4. ANY suggested remans to buy OR all about the same. Autozone can have one for me today for about $220.
5. Do I have to get codes cleared/re set since battery has now been removed?
6. Are presets of any of the car from radio to personal settings saved by chance?
Thanks for any feedback?
David/TOO freaking HOT Dallas
Thread Starter
Melting Slicks
Joined: Aug 2008
Posts: 2,561
Likes: 1
From: Oakland Ca
St. Jude Donor '09
Instructor
Joined: Aug 2010
Posts: 170
Likes: 5
update prior to any possible suggestions
Old battery was charged at Autozone put in car showed 12.6 volts. left driving yet volt meter read like 10-11 volts in car so I thought it must be the alternator. I got on it once and volt meter showed like 13.7 volts and drove back to Autozone to have test done on battery and alternator.
BOTH showed to be working in good order.
So which is more probable? Intermittent alternator or battery going bad.........but if so how did it just hold a charge back up to 12.7 volts at Autozone?
I am carrying the new battery with me in case either fail while driving but how do I confirm which is bad now!!
Thanks......any ideas?
BOTH showed to be working in good order.
So which is more probable? Intermittent alternator or battery going bad.........but if so how did it just hold a charge back up to 12.7 volts at Autozone?
I am carrying the new battery with me in case either fail while driving but how do I confirm which is bad now!!
Thanks......any ideas?
Le Mans Master
Joined: Jul 2009
Posts: 9,526
Likes: 12
From: Los Angeles California
I've found that this problem often is a symptom of the ground terminal not being tight enough. When I see that message come up, I make sure the terminals are tight enough. If they're tight, I check the ground points.
Definitely keep that alternator as a backup! The only alternators that work for C5s correctly are the ones made in France. If you don't get the right alternator, you end up getting charge fault messages all the time. I'm worried about when they stop making that alternator...
Definitely keep that alternator as a backup! The only alternators that work for C5s correctly are the ones made in France. If you don't get the right alternator, you end up getting charge fault messages all the time. I'm worried about when they stop making that alternator...
Racer
Joined: Mar 2011
Posts: 337
Likes: 1
From: Mechanicsville Md
Speaking of neg battery ground. I got a wire that's connected to the battery ground that goes to a jumper. The other side of the jumper goes back to the ground. Both wires are black but one has a red ring around it. It doesnt seem right to have both wires go the the negative terminal and equally doesn't seem right to one going to the positive lead. Any thoughts?
