) 
Alternator: Look at this pic
Thread Starter
On The Tree
iTrader: (3)
Joined: Mar 2004
Posts: 166
Likes: 0
From: North Hollywood, CA
Alternator: Look at this pic Hello everyone. Here is a pic of my alternator gauge:
This is where it sits after the motor is warm and I've been sitting in traffic. Is this normal? The car seems fine.
When I turn on the headlights, the gauge jumps to 13. Strange thing is, when it's warm, if I turn on the car and leave the parking brake up, it sits right above 13. Once I put the parking brake down and the DRL's come on, it drops to where it is on the pic.
Any ideas?
This is where it sits after the motor is warm and I've been sitting in traffic. Is this normal? The car seems fine.
When I turn on the headlights, the gauge jumps to 13. Strange thing is, when it's warm, if I turn on the car and leave the parking brake up, it sits right above 13. Once I put the parking brake down and the DRL's come on, it drops to where it is on the pic.
Any ideas?
Thread Starter
On The Tree
iTrader: (3)
Joined: Mar 2004
Posts: 166
Likes: 0
From: North Hollywood, CA
This is my third alternator in two months. The first two were rebuilt alts from the local auto parts distributor. Those took a dump, so I found an OE alternator from another member here. This one has about 30K miles and was supposedly working just fine when it was removed.
Thread Starter
On The Tree
iTrader: (3)
Joined: Mar 2004
Posts: 166
Likes: 0
From: North Hollywood, CA
Trending Topics
Try a fresh battery, a battery that draws alot of load increases the output required by the alternator and actually drags down voltage, I have seen anywhere from .5-1.0 volt increase on average with a fresh battery, and yes I have seen one battery take out several alternators.
You will be able to see it happen if you have a battery tester with a amp meter. If you check the amperage output before and after a good battery you will see the amperage drop and voltage go up ( alternator not working as hard can output more voltage easily )
That is where I would start, otherwise I would say its the alternator had you not given the history.
Technician/Service Manager for 10 years, so I didnt pull this out my ****.
Edit, the exciter wire does only two things, turns on the alternator at startup and if the alternator fails that wire connects directly to the battery light and turns it on, so dont bother with it, if you have real high resistance in the wire from the alt to the battery that could be a problem, check it with a DVOM.
You will be able to see it happen if you have a battery tester with a amp meter. If you check the amperage output before and after a good battery you will see the amperage drop and voltage go up ( alternator not working as hard can output more voltage easily )
That is where I would start, otherwise I would say its the alternator had you not given the history.
Technician/Service Manager for 10 years, so I didnt pull this out my ****.
Edit, the exciter wire does only two things, turns on the alternator at startup and if the alternator fails that wire connects directly to the battery light and turns it on, so dont bother with it, if you have real high resistance in the wire from the alt to the battery that could be a problem, check it with a DVOM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
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
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
On The Tree
iTrader: (3)
Joined: Mar 2004
Posts: 166
Likes: 0
From: North Hollywood, CA
Sorry I didn't include the history of the battery. The batter is brand new and I made sure it was fully charged by placing it on my battery charger. The charger said full charge before I even fired up the car with this third alternator.
Also, is that really all the exciter wire does? I have read stuff on this forum saying that it tells the alternator how much power to put out depending on what the PCM is saying. Beats me.
Also, is that really all the exciter wire does? I have read stuff on this forum saying that it tells the alternator how much power to put out depending on what the PCM is saying. Beats me.
Only other thing I could think of is if you have a seriously demanding audio system (or something else) that is making the alternator over work. If thats the case, then moving up to a bigger (higher output) alternator may be a thing to do.
Thread Starter
On The Tree
iTrader: (3)
Joined: Mar 2004
Posts: 166
Likes: 0
From: North Hollywood, CA
I still have the stock Monsoon system. Weird thing is on my SS, I have the stock alternator and am running two amps, one for a sub and one for my speakers, an MSD Digital 7, and an Aeromotive A1000. I don't have any of these issues with my SS and it has far more electronics equipment installed.
TECH Enthusiast
Joined: Feb 2005
Posts: 734
Likes: 0
From: south jersey. again
cheap rebuilt alternators arent worth the time and money, no matter how good the warranty. they could do damage if they arent built right possible overcharging the battery. im not saying yours is doing this but i have seen it happen. if you bought it from an autozone or somewhere similar, they should be able to test your system out. sometimes its worthwhile to spend a little more with a reputable mechanic than to guess what a problem is.
Thread Starter
On The Tree
iTrader: (3)
Joined: Mar 2004
Posts: 166
Likes: 0
From: North Hollywood, CA
cheap rebuilt alternators arent worth the time and money, no matter how good the warranty. they could do damage if they arent built right possible overcharging the battery. im not saying yours is doing this but i have seen it happen. if you bought it from an autozone or somewhere similar, they should be able to test your system out. sometimes its worthwhile to spend a little more with a reputable mechanic than to guess what a problem is.
Teching In
Joined: Oct 2008
Posts: 40
Likes: 0
From: The 717
Not exactly sure how much the front accessories differ from the lsx motor, but this exact same thing kept happening to a friend of mine. He kept taking his alt back to Autozone for a new one, and we were out one day and the thing died again...
We got out and looked at the alternator and there was a little bit of power steering fluid dripping into the alternator causing it to short out! A fitting on the resevoir had cracked and was leaking fluid. He brought back the alternator, and we went to a different parts store to buy a new power steering resevoir.
We got out and looked at the alternator and there was a little bit of power steering fluid dripping into the alternator causing it to short out! A fitting on the resevoir had cracked and was leaking fluid. He brought back the alternator, and we went to a different parts store to buy a new power steering resevoir.
Thread Starter
On The Tree
iTrader: (3)
Joined: Mar 2004
Posts: 166
Likes: 0
From: North Hollywood, CA
Not exactly sure how much the front accessories differ from the lsx motor, but this exact same thing kept happening to a friend of mine. He kept taking his alt back to Autozone for a new one, and we were out one day and the thing died again...
We got out and looked at the alternator and there was a little bit of power steering fluid dripping into the alternator causing it to short out! A fitting on the resevoir had cracked and was leaking fluid. He brought back the alternator, and we went to a different parts store to buy a new power steering resevoir.
We got out and looked at the alternator and there was a little bit of power steering fluid dripping into the alternator causing it to short out! A fitting on the resevoir had cracked and was leaking fluid. He brought back the alternator, and we went to a different parts store to buy a new power steering resevoir.
Teching In
Joined: Oct 2008
Posts: 40
Likes: 0
From: The 717
My friend and I never noticed it either until the time we broke down. There was a very small amount, but we actually saw it drip and fall right into the alternator. He's hd no problems since it was fixed.
TECH Addict
Joined: Nov 2005
Posts: 2,379
Likes: 2
If you have a m6 with an underdrive, you will not notice a drop at idle with the stock alternator.
typical m6 idle rpm is 800 -25% underdrive = 600rpm
An auto in gear will spin about 600rpm yet has enough power output from the alternator to be fine.
Use a voltmeter and check the voltage while the car is showing this on the guage. If >12V, alternator is still functional but something is drawing quite a bit of power. 13-14V is typical for alternator output depending on the load of the system. If <12V, you aren't running off the alternator.
typical m6 idle rpm is 800 -25% underdrive = 600rpm
An auto in gear will spin about 600rpm yet has enough power output from the alternator to be fine.
Use a voltmeter and check the voltage while the car is showing this on the guage. If >12V, alternator is still functional but something is drawing quite a bit of power. 13-14V is typical for alternator output depending on the load of the system. If <12V, you aren't running off the alternator.
yeah it could be something else getting into the alternator, might be worth checking out. I used to work at an autoparts store and people would bring in alternators covered in oil time and time again and ask us to replace under warranty....
Wiring would be to the battery is what I was thinking of. I doubt it is the battery, but anything is a possibility with electrical systems
Wiring would be to the battery is what I was thinking of. I doubt it is the battery, but anything is a possibility with electrical systems
Sorry I didn't include the history of the battery. The batter is brand new and I made sure it was fully charged by placing it on my battery charger. The charger said full charge before I even fired up the car with this third alternator.
Also, is that really all the exciter wire does? I have read stuff on this forum saying that it tells the alternator how much power to put out depending on what the PCM is saying. Beats me.
Also, is that really all the exciter wire does? I have read stuff on this forum saying that it tells the alternator how much power to put out depending on what the PCM is saying. Beats me.
Sorry I haven't looked into these cars specifically and right now I have no access to a data system that I could check that with, some cars do yes have PCM controlled output, but I think these cars have internally regulated alternators, I would have to look at the wiring diagram. Most diagrams show a hot wire that excites ( gets hot/positive power ) when you turn the key to on and that wire runs through the battery light to the alternator, if all is good it turns on the alt and it starts charging once it sees RPM, if the alt is bad it is supposed to ground that wire which would cause the light to come on since you now have ground and hot on each side of the batt bulb.
I would think there would be more than one wire on a PCM controlled output vehicle, could be wrong, havent ever actually studied that exact situation.
DO you have an underdrive??? If so all this went out the window, it will charge less with an underdrive, if you want absolute confirmation on what is causing it you would have to swap parts with your other car. Do one at a time, starting with the easiest.
BUT BEFORE you do anything confirm your gauges accuracy with a volt meter, that should be step one in your diagnosis of the problem.