Bad Alternator (Part II)
Bad Alternator (Part II) Two months ago I replaced the stock alternator with a new AC Delco in my 2000 Camaro (LS1). I drove the car a few times and I started seeing the same pattern of "bad alternator" symptoms again as my battery voltage gage started drifting to the left and dropping as the car was running. I had a shop take the AC Delco alternator out, and after testing it.... they said it was not charging. Thank God I have a lifetime warranty on the alternator so I replaced it with another one....AC Delco of course. The shop put in the replaced alternator and the car started and my voltage gage was at normal reading (13 volts). Today I ran the car from a dig and after hitting 80 mph I noticed my "check gages" sign light up. Well, I'm back on the "bad alternator" symptom again. Voltage gage is now in the red again when the car is running. I thinking this AC Delco just can't handle 400HP or something, makes no sense. 
Do you have any sort of aftermarket electronics (radio, amp, etc) that may be putting a big load on the electrical system ? Or is it possible you have a battery with a weak cell ? You can easily burn up an alternator putting too much load on it.
I see what you're saying but this wasn't an issue for my stock alternator which gave me over 100,000 miles of performance. After replacing that stock alternator, the new one seems to give out when I accelerate hard.
Just an FYI in my 2000 Z the thin wire going from alternator up to (don't remember) was bad. We tested this by using another wire. Once we figured it out we found the break and spliced a new wire on before it. Fixed all the issues.
Might try it.
Might try it.
I thought AC Delco stopped making alternators? I bought my replacement ones from O'Riellys and never had a problem. It was the Ultima Alternator.. Maybe return that AutoZone one and get O'Reilly's?
Trending Topics
Step one: Get an Optima battery. They're not what they used to be but still the best.
Step two: Replace the pigtail/connector http://cgi.ebay.com/ebaymotors/LS1-A...lenotsupported
Step three: Upgrade your big 3, add 4/2/0 gauge to -
Battery POS to Alternator
Battery NEG to chassis
Engine to chassis ground
This is a good idea whether you have a stereo system or not. It allows more current to flow through the entire circuit, pulling more juice from your alt. with less strain.
Step four (if you still have issues): Get a high output or locally rebuilt unit.
OEM units were good, Delco remans, decent at best, and AZ are HORRIBLE. OReilly's not much better. Napa, on par with Delco remans. Your best bet is a US built reman, factory or high output. Check ebay and local alternator shops.
Also remember, some fluctuation is normal, especially when you first kick on the AC or fan to a high setting. Our volt gauges are only indicators and relative at best. If you've pulled the needles, like for an overlay, it's even worse.
Check to make sure you're not getting oil or PS fluid on the damn thing. That's a common killer. If you've been through high water, same deal. Still have the factory tensioner? A belt that is too tight or too loose could also give you issues.
Keep us posted.
Step two: Replace the pigtail/connector http://cgi.ebay.com/ebaymotors/LS1-A...lenotsupported
Step three: Upgrade your big 3, add 4/2/0 gauge to -
Battery POS to Alternator
Battery NEG to chassis
Engine to chassis ground
This is a good idea whether you have a stereo system or not. It allows more current to flow through the entire circuit, pulling more juice from your alt. with less strain.
Step four (if you still have issues): Get a high output or locally rebuilt unit.
OEM units were good, Delco remans, decent at best, and AZ are HORRIBLE. OReilly's not much better. Napa, on par with Delco remans. Your best bet is a US built reman, factory or high output. Check ebay and local alternator shops.
Also remember, some fluctuation is normal, especially when you first kick on the AC or fan to a high setting. Our volt gauges are only indicators and relative at best. If you've pulled the needles, like for an overlay, it's even worse.
Check to make sure you're not getting oil or PS fluid on the damn thing. That's a common killer. If you've been through high water, same deal. Still have the factory tensioner? A belt that is too tight or too loose could also give you issues.
Keep us posted.
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
the little red devil wire..its a red wire that goes to the connector that plugs into the alternator. make sure its not pulled out of the connector. i went threw the same **** as you. the problem with them pulling out of the connector is when you let the alternator hang the red wire will pull out of the connector for some reason. if you have a short somewhere then it will spark at the batter when you try and connect it
Sparking at the battery will almost always happen. I pull/disconnect batteries everyday and a small spark is not unusual at all.
I had alternator problems for a long time till mine finally gave out. Including the auto tranny slipping and shifting weird, as well as cause my amp to turn off for a couple seconds when it's under a heavy load.
My fix was to buy a Bosch HO alternator. It's not much of an upgrade (102 amp instead of the factory 95), but that sum bitch was awesome. If you can find a shop (doesn't have to be a chevy specialist) that is a Bosch dealer, ask them if they'll order you one. I recommend it...
I had alternator problems for a long time till mine finally gave out. Including the auto tranny slipping and shifting weird, as well as cause my amp to turn off for a couple seconds when it's under a heavy load.
My fix was to buy a Bosch HO alternator. It's not much of an upgrade (102 amp instead of the factory 95), but that sum bitch was awesome. If you can find a shop (doesn't have to be a chevy specialist) that is a Bosch dealer, ask them if they'll order you one. I recommend it...
Teching In
Joined: Apr 2009
Posts: 1
Likes: 0
From: Dallas, Tx.
Would like to know how the bosch alt. is still holding up if possible? Also what the fix was to the original thread issue. I have a factory alt. going out and would like a little info before making my purchase. Already upgraded the wiring and battery. Thanks for any help.
Step one: Get an Optima battery. They're not what they used to be but still the best.
Step two: Replace the pigtail/connector http://cgi.ebay.com/ebaymotors/LS1-A...lenotsupported
Step three: Upgrade your big 3, add 4/2/0 gauge to -
Battery POS to Alternator
Battery NEG to chassis
Engine to chassis ground
This is a good idea whether you have a stereo system or not. It allows more current to flow through the entire circuit, pulling more juice from your alt. with less strain.
Step four (if you still have issues): Get a high output or locally rebuilt unit.
OEM units were good, Delco remans, decent at best, and AZ are HORRIBLE. OReilly's not much better. Napa, on par with Delco remans. Your best bet is a US built reman, factory or high output. Check ebay and local alternator shops.
Also remember, some fluctuation is normal, especially when you first kick on the AC or fan to a high setting. Our volt gauges are only indicators and relative at best. If you've pulled the needles, like for an overlay, it's even worse.
Check to make sure you're not getting oil or PS fluid on the damn thing. That's a common killer. If you've been through high water, same deal. Still have the factory tensioner? A belt that is too tight or too loose could also give you issues.
Keep us posted.
Step two: Replace the pigtail/connector http://cgi.ebay.com/ebaymotors/LS1-A...lenotsupported
Step three: Upgrade your big 3, add 4/2/0 gauge to -
Battery POS to Alternator
Battery NEG to chassis
Engine to chassis ground
This is a good idea whether you have a stereo system or not. It allows more current to flow through the entire circuit, pulling more juice from your alt. with less strain.
Step four (if you still have issues): Get a high output or locally rebuilt unit.
OEM units were good, Delco remans, decent at best, and AZ are HORRIBLE. OReilly's not much better. Napa, on par with Delco remans. Your best bet is a US built reman, factory or high output. Check ebay and local alternator shops.
Also remember, some fluctuation is normal, especially when you first kick on the AC or fan to a high setting. Our volt gauges are only indicators and relative at best. If you've pulled the needles, like for an overlay, it's even worse.
Check to make sure you're not getting oil or PS fluid on the damn thing. That's a common killer. If you've been through high water, same deal. Still have the factory tensioner? A belt that is too tight or too loose could also give you issues.
Keep us posted.
I can't stand vehicles with leaking fluids. 
Staging Lane
Joined: Dec 2007
Posts: 92
Likes: 0
From: odessa, tx
i have had the same problem for two years now...i just gave up i had it in three different shops and tried everything i read on this site and still have issues. I have been through 9 alternators..i have to turn the ac off before i get on it or it burns the alt everytime and sometimes even with the ac off.
i have had the same problem for two years now...i just gave up i had it in three different shops and tried everything i read on this site and still have issues. I have been through 9 alternators..i have to turn the ac off before i get on it or it burns the alt everytime and sometimes even with the ac off.
Anyone with alternator problems read this
https://ls1tech.com/forums/generatio...-failures.html
And by the way this was roughly in the range of 15k miles ago, actually probably closer to 20. I don't know the mileage my car had at the time. I had problems with my rebuilds/new units failing within minutes too within months, several failed right after a WOT pull. One died in 5 minutes, with no WOT pull, just putt-ing down the highway, I made it all of 5 miles, and that was with all wiring being good and a new pigtail. And it explains in the thread how I checked everything, even with no system running just factory electronics the alternators would stop charging in 20 minutes at idle.
All of my problems started immediately after replacing the 150ish thousand mile factory unit.
https://ls1tech.com/forums/generatio...-failures.html
And by the way this was roughly in the range of 15k miles ago, actually probably closer to 20. I don't know the mileage my car had at the time. I had problems with my rebuilds/new units failing within minutes too within months, several failed right after a WOT pull. One died in 5 minutes, with no WOT pull, just putt-ing down the highway, I made it all of 5 miles, and that was with all wiring being good and a new pigtail. And it explains in the thread how I checked everything, even with no system running just factory electronics the alternators would stop charging in 20 minutes at idle.
All of my problems started immediately after replacing the 150ish thousand mile factory unit.
Last edited by 00pooterSS; Apr 5, 2011 at 10:29 PM.
Anyone with alternator problems read this
https://ls1tech.com/forums/generatio...-failures.html
And by the way this was roughly in the range of 15k miles ago, actually probably closer to 20. I don't know the mileage my car had at the time. I had problems with my rebuilds/new units failing within minutes too within months, several failed right after a WOT pull. One died in 5 minutes, with no WOT pull, just putt-ing down the highway, I made it all of 5 miles, and that was with all wiring being good and a new pigtail. And it explains in the thread how I checked everything, even with no system running just factory electronics the alternators would stop charging in 20 minutes at idle.
All of my problems started immediately after replacing the 150ish thousand mile factory unit.
https://ls1tech.com/forums/generatio...-failures.html
And by the way this was roughly in the range of 15k miles ago, actually probably closer to 20. I don't know the mileage my car had at the time. I had problems with my rebuilds/new units failing within minutes too within months, several failed right after a WOT pull. One died in 5 minutes, with no WOT pull, just putt-ing down the highway, I made it all of 5 miles, and that was with all wiring being good and a new pigtail. And it explains in the thread how I checked everything, even with no system running just factory electronics the alternators would stop charging in 20 minutes at idle.
All of my problems started immediately after replacing the 150ish thousand mile factory unit.
The reman alt's you're likely getting are crap - Upgrade it to an alternator from a Yukon/Tahoe/etc that is 145amps instead of 105amps and you'll be good to go. While you're doing it, do the Big 3 upgrade as well - I had the exact same issues after my stock alternator bit the dust and went through 5 "new" alternators before finding one for $60 at a junk yard that was 100x better. The other option is to pay $200 bucks to have your current alternator "upgraded" by a local electrical shop.
Guys, I failed to mention one thing that IS the problem and addresses pooter:
F body alternators DO NOT LIKE HIGH RPMs. If you bang 6000+ RPMs regularly, you will eat alternators. They are not designed for it. Corvette units are better at dealing with revs, same deal with AC compressors. Get a high quality US rebuild and you'll be much better off. Best alternative is a HO unit with a larger pulley so the RPMs are kept down but you still get plenty of juice.
F body alternators DO NOT LIKE HIGH RPMs. If you bang 6000+ RPMs regularly, you will eat alternators. They are not designed for it. Corvette units are better at dealing with revs, same deal with AC compressors. Get a high quality US rebuild and you'll be much better off. Best alternative is a HO unit with a larger pulley so the RPMs are kept down but you still get plenty of juice.