Voltage Problem with good Battery and Alternator
Thread Starter
Launching!
Joined: Jun 2010
Posts: 238
Likes: 0
From: Jacksonville, FL
Voltage Problem with good Battery and Alternator Sunday I was driving home from a car show and I saw my check gauges light come on, I look down and my voltage is just bearly low in the red zone. Normally my voltage is 14 or 15 volts. My voltage gauge would rise up to about 11.5 volts and the light would shut off, then drop back down to 11 volts (bearly in the red zone) and the light would come on. It repated this the rest of the drive.
Monday I took both battery and alternator out of the car to get tested. Alternator passed the test 3 times in a row. Battery tested low on cranking amps and my buddy wrote it off under warranty and I got a new battery. Went home and installed everything back and the same problem still occurs. I started the car and it warmed up with the proper voltage, but during my drive to work the check gauges light came back on and my low voltage was back at around 11 volts and then rising back up and down...
Tonight I checked my power wire from my battery, everything looks like it has a good connection. Going to check again tomorrow in better light.
5 or 6 months ago my orignal delphi alternator went out and I replaced it with a NEW Remy 145 amp truck alternator.
I had to replace my flexplate back in november and when I put my starter back in I didnt ziptie my power wire from battery to starter away from my exhaust and the harness case and wire case melted. When I would have a hard 1-2 shift the bare wire would hit my header and short out the car. I found that quick, and the wire looked good still (could still see threads of wire) so I re-covered the wire with a couple layers of electric tape and put some new harness cover over it and its been fine. I dont think that could cause my problem, but I'm thowing it out there.
Anyone have any idea what could cause this low voltage/voltage fluctuation with a NEW Battery and a GOOD fairly new Alternator?
Thanks Tech
Monday I took both battery and alternator out of the car to get tested. Alternator passed the test 3 times in a row. Battery tested low on cranking amps and my buddy wrote it off under warranty and I got a new battery. Went home and installed everything back and the same problem still occurs. I started the car and it warmed up with the proper voltage, but during my drive to work the check gauges light came back on and my low voltage was back at around 11 volts and then rising back up and down...
Tonight I checked my power wire from my battery, everything looks like it has a good connection. Going to check again tomorrow in better light.
5 or 6 months ago my orignal delphi alternator went out and I replaced it with a NEW Remy 145 amp truck alternator.
I had to replace my flexplate back in november and when I put my starter back in I didnt ziptie my power wire from battery to starter away from my exhaust and the harness case and wire case melted. When I would have a hard 1-2 shift the bare wire would hit my header and short out the car. I found that quick, and the wire looked good still (could still see threads of wire) so I re-covered the wire with a couple layers of electric tape and put some new harness cover over it and its been fine. I dont think that could cause my problem, but I'm thowing it out there.
Anyone have any idea what could cause this low voltage/voltage fluctuation with a NEW Battery and a GOOD fairly new Alternator?
Thanks Tech
Thread Starter
Launching!
Joined: Jun 2010
Posts: 238
Likes: 0
From: Jacksonville, FL
No I have not checked vom @ bat. Will when I get a meter
It was definitely toasted but still intact. Not melted i wouldnt say. I figured it would still be able to transmit current the same. What you think?
Also, forgot to say this orignially but my turnsignals blink slower than normal and my gauges are slightly dimmer than normal.
It was definitely toasted but still intact. Not melted i wouldnt say. I figured it would still be able to transmit current the same. What you think?
Also, forgot to say this orignially but my turnsignals blink slower than normal and my gauges are slightly dimmer than normal.
Joined: Nov 2001
Posts: 34,647
Likes: 2,574
From: Schiller Park, ILL Member: #317
Sounds to me like the alternator "test" probably didn't tell the whole story. Based on your post, the unit seems to charge fine until it heats up. They don't usually test them for very long, and sometimes the issue will not be present during such a short duration and low amount of heat.
Years ago, I went through something similar on my 3rd gen. I replaced a failed alternator and still had charging issues. So just like you, I then suspected wiring and connections/shorts/etc. My battery and (new) alternator had also been "tested" and passed without issues. I finally gave up after lots of wiring replacements and frustration, and I bought a higher quality alternator (first one was a cheap rebuild from a local parts store). This fixed the problem.
Moral of the story.....their "test" did not show that the alternator had any issue, because the only time it would have charging problems was after extended engine run time. If I had believed their test, then I never would have gotten that car fixed...lol.
Years ago, I went through something similar on my 3rd gen. I replaced a failed alternator and still had charging issues. So just like you, I then suspected wiring and connections/shorts/etc. My battery and (new) alternator had also been "tested" and passed without issues. I finally gave up after lots of wiring replacements and frustration, and I bought a higher quality alternator (first one was a cheap rebuild from a local parts store). This fixed the problem.
Moral of the story.....their "test" did not show that the alternator had any issue, because the only time it would have charging problems was after extended engine run time. If I had believed their test, then I never would have gotten that car fixed...lol.
Is the problem intermittant?
When the lights start dimming/blinkers slowing, do they continue this way, or do they recover at some point (lights revert back to normal)?
The exciter wire plug at the alternator should have between 5>9 volts on it with the connector removed. If so, is the proper voltage measured at the battery?
Also, try checking for parasitic current loss at the battery & fuse box.
Last edited by gMAG; Feb 29, 2012 at 12:21 AM.
Trending Topics
Thread Starter
Launching!
Joined: Jun 2010
Posts: 238
Likes: 0
From: Jacksonville, FL
Sorry man, like 5 mins after I posted it it was 3 pages deep in "new posts" and I cant find **** about my problem, so I was wanting people to see it. and it worked. My bad tho, I hesitated to bump that quick and now you call me out lol 
Wanna throw your 2 cents in? I know you have alot of knowledge with these cars
The alt was my first guess. I've never had anything but an alternator cause these symptoms during driving. The tests were definitely short, no more than 15 seonds, and had no heat present.
What happened with you 3rd gen sounds like what I'm going through. When I got a new alternator, I made a point to get a brand new one. Does anyone have anything bad to say about Remy alternators? I did notice when I got it checked monday it had a made in mexico sticker on it
...
Do you think testing it on another machine will yield different results?
It was intermintent at first, as in voltage would rise and drop between the voltages I described in post 1, but now (after driving the car yesterday), the battery stays low on voltage and the check gauges light stays on. I'm gusesing this just due to insufficient charge from the alt and the bat is slowly draining. At first the lights and turn signals would act normal when the voltage rises, but its not rising up out of the red zone anymore so they are still dim and slow. I'm about to ride home from my gf's apartment and pick up meter on the way. Thanks alot gMag
Wanna throw your 2 cents in? I know you have alot of knowledge with these cars
Sounds to me like the alternator "test" probably didn't tell the whole story. Based on your post, the unit seems to charge fine until it heats up. They don't usually test them for very long, and sometimes the issue will not be present during such a short duration and low amount of heat.
Years ago, I went through something similar on my 3rd gen. I replaced a failed alternator and still had charging issues. So just like you, I then suspected wiring and connections/shorts/etc. My battery and (new) alternator had also been "tested" and passed without issues. I finally gave up after lots of wiring replacements and frustration, and I bought a higher quality alternator (first one was a cheap rebuild from a local parts store). This fixed the problem.
Moral of the story.....their "test" did not show that the alternator had any issue, because the only time it would have charging problems was after extended engine run time. If I had believed their test, then I never would have gotten that car fixed...lol.
Years ago, I went through something similar on my 3rd gen. I replaced a failed alternator and still had charging issues. So just like you, I then suspected wiring and connections/shorts/etc. My battery and (new) alternator had also been "tested" and passed without issues. I finally gave up after lots of wiring replacements and frustration, and I bought a higher quality alternator (first one was a cheap rebuild from a local parts store). This fixed the problem.
Moral of the story.....their "test" did not show that the alternator had any issue, because the only time it would have charging problems was after extended engine run time. If I had believed their test, then I never would have gotten that car fixed...lol.
What happened with you 3rd gen sounds like what I'm going through. When I got a new alternator, I made a point to get a brand new one. Does anyone have anything bad to say about Remy alternators? I did notice when I got it checked monday it had a made in mexico sticker on it
... Do you think testing it on another machine will yield different results?
Because the engine starts, and the starter is used so little, this wouldn't be an issue
Is the problem intermittant?
When the lights start dimming/blinkers slowing, do they continue this way, or do they recover at some point (lights revert back to normal)?
The exciter wire plug at the alternator should have between 5>9 volts on it with the connector removed. If so, is the proper voltage measured at the battery?
Also, try checking for parasitic current loss at the battery & fuse box.
Is the problem intermittant?
When the lights start dimming/blinkers slowing, do they continue this way, or do they recover at some point (lights revert back to normal)?
The exciter wire plug at the alternator should have between 5>9 volts on it with the connector removed. If so, is the proper voltage measured at the battery?
Also, try checking for parasitic current loss at the battery & fuse box.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Thread Starter
Launching!
Joined: Jun 2010
Posts: 238
Likes: 0
From: Jacksonville, FL
Alternator was what I first thought it was. It showed the exact symptoms of a bad alternator, except I've never seen the charge changing so much.
My alternator is under warranty, cannot sufficiently charge my battery, but passed the test ... I dont wanna throw out 150+ for a new one if mine is under warranty. I'll have to get my buddy at Advanced to just write it off if it passes the test again
My alternator is under warranty, cannot sufficiently charge my battery, but passed the test ... I dont wanna throw out 150+ for a new one if mine is under warranty. I'll have to get my buddy at Advanced to just write it off if it passes the test again
Thread Starter
Launching!
Joined: Jun 2010
Posts: 238
Likes: 0
From: Jacksonville, FL
Thats what I've heard, so I stayed away from remanufactured alts. I made sure I got a NEW one. I know the originals are the best but there are not many junkyards around me. So the next best thing was a new one from Advanced. Thought it being new, not reman'd, would be safe but I guess I was wrong bc 5 or 6 months of life from a new unit is bs.
Right now I have my new battery I got Mon in my 3rd gen so I can charge it back up on my drive to work, and not fry it out trying to run on insufficient power in the camaro
Right now I have my new battery I got Mon in my 3rd gen so I can charge it back up on my drive to work, and not fry it out trying to run on insufficient power in the camaro
TECH Resident
Joined: Nov 2011
Posts: 812
Likes: 0
From: NJ
Sunday I was driving home from a car show and I saw my check gauges light come on, I look down and my voltage is just bearly low in the red zone. Normally my voltage is 14 or 15 volts. My voltage gauge would rise up to about 11.5 volts and the light would shut off, then drop back down to 11 volts (bearly in the red zone) and the light would come on. It repated this the rest of the drive.
Monday I took both battery and alternator out of the car to get tested. Alternator passed the test 3 times in a row. Battery tested low on cranking amps and my buddy wrote it off under warranty and I got a new battery. Went home and installed everything back and the same problem still occurs. I started the car and it warmed up with the proper voltage, but during my drive to work the check gauges light came back on and my low voltage was back at around 11 volts and then rising back up and down...
Tonight I checked my power wire from my battery, everything looks like it has a good connection. Going to check again tomorrow in better light.
5 or 6 months ago my orignal delphi alternator went out and I replaced it with a NEW Remy 145 amp truck alternator.
I had to replace my flexplate back in november and when I put my starter back in I didnt ziptie my power wire from battery to starter away from my exhaust and the harness case and wire case melted. When I would have a hard 1-2 shift the bare wire would hit my header and short out the car. I found that quick, and the wire looked good still (could still see threads of wire) so I re-covered the wire with a couple layers of electric tape and put some new harness cover over it and its been fine. I dont think that could cause my problem, but I'm thowing it out there.
Anyone have any idea what could cause this low voltage/voltage fluctuation with a NEW Battery and a GOOD fairly new Alternator?
Thanks Tech
Monday I took both battery and alternator out of the car to get tested. Alternator passed the test 3 times in a row. Battery tested low on cranking amps and my buddy wrote it off under warranty and I got a new battery. Went home and installed everything back and the same problem still occurs. I started the car and it warmed up with the proper voltage, but during my drive to work the check gauges light came back on and my low voltage was back at around 11 volts and then rising back up and down...
Tonight I checked my power wire from my battery, everything looks like it has a good connection. Going to check again tomorrow in better light.
5 or 6 months ago my orignal delphi alternator went out and I replaced it with a NEW Remy 145 amp truck alternator.
I had to replace my flexplate back in november and when I put my starter back in I didnt ziptie my power wire from battery to starter away from my exhaust and the harness case and wire case melted. When I would have a hard 1-2 shift the bare wire would hit my header and short out the car. I found that quick, and the wire looked good still (could still see threads of wire) so I re-covered the wire with a couple layers of electric tape and put some new harness cover over it and its been fine. I dont think that could cause my problem, but I'm thowing it out there.
Anyone have any idea what could cause this low voltage/voltage fluctuation with a NEW Battery and a GOOD fairly new Alternator?
Thanks Tech
it sounds like the voltage regulator(which is in the alt) is failing.
Joined: Nov 2001
Posts: 34,647
Likes: 2,574
From: Schiller Park, ILL Member: #317
The only replacement alternators I've ever had good luck with have been directly from GM or from Powermaster.
All of the other retail parts store units I've ever bought (AutoZone/Advance/Pep Boys/etc.) have always been disappointing and/or failed in the short term.
All of the other retail parts store units I've ever bought (AutoZone/Advance/Pep Boys/etc.) have always been disappointing and/or failed in the short term.
TECH Resident
Joined: Nov 2011
Posts: 812
Likes: 0
From: NJ
stay away from pep bois, autozone, advanced, etc. if you don't want dealer reman/new, try napa. i use their alternators/starters almost exclusively, with zero problems.
Thread Starter
Launching!
Joined: Jun 2010
Posts: 238
Likes: 0
From: Jacksonville, FL
Well I took my alt out and up to my buddy at advanced and exchanged it under warranty for a new one. I've drove the car 16 miles tonight and I've had a consistent 14 volts so it looks like it was the alternator. Good call RPM ws6 and ls6 427! And thanks to everyone who helped out. Looks like I'm possibly stuck replacing these things until ones outlasts warranty
TECH Resident
Joined: Nov 2011
Posts: 812
Likes: 0
From: NJ
Well I took my alt out and up to my buddy at advanced and exchanged it under warranty for a new one. I've drove the car 16 miles tonight and I've had a consistent 14 volts so it looks like it was the alternator. Good call RPM ws6 and ls6 427! And thanks to everyone who helped out. Looks like I'm possibly stuck replacing these things until ones outlasts warranty
Joined: Nov 2001
Posts: 34,647
Likes: 2,574
From: Schiller Park, ILL Member: #317
The LS1 alternators are all CS series, I'm not sure if the truck units are considered part of the same design series, but I imagine they would be.
Anyway, if you are using a factory belt tensioner and properly sized belt, then I don't see how belt tension could ever be too tight.
I think you just got a junk alternator the first time. Hopefully this second one will be better, but I wouldn't count too much on it.
Anyway, if you are using a factory belt tensioner and properly sized belt, then I don't see how belt tension could ever be too tight.
I think you just got a junk alternator the first time. Hopefully this second one will be better, but I wouldn't count too much on it.