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Posted: 7/25/2013 11:28:45 AM EDT
So,
Vehicle in question is a '97 Toyota Avalon with 91,000 miles on it.  So today as I'm going about on errands, I notice the battery idiot light is on and I'm like .  No probs.  On the way back from the first stop (getting a blower fan for the home AC), I notice the battery AND ABS idiot lights are on, and I'm like .  As I'm driving (rural highway so 1-5 miles between lights), I come to the next red light.  I stop (duh) and then I noticed that when I hit the brakes, the radio turned off....  As I get to the next red light, I stop (duh)...when it's green, I notice the car is barely accelerating.  It's not sputtering or anything, it's just not going so I start hitting switches and when I turn off the interior fan, then it starts like there's no problem.  I'm in the home stretch..at least hoping I make it home....and I notice as I turn on the turn signal, the tach needle is pulsing with the "beat" of the signal.  

So, WTF is wrong?  Low battery?  Fuse?  Alternator?  <-------- pretty much the extent of my knowledge on a car's electrical system.
Link Posted: 7/25/2013 11:36:31 AM EDT
[#1]
alternator not charging battery - car running off battery and it's dead



charge battery - check alternator  - if it's good check ALL your wiring


just had the same issue, changed my battery x2 and alternator x2 - ended up being one corroded wire - bypassed that and all is good now
Link Posted: 7/25/2013 12:52:55 PM EDT
[#2]
sounds like the alternator quit working
Link Posted: 7/25/2013 12:54:55 PM EDT
[#3]

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Quoted:


sounds like the alternator quit working
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Link Posted: 7/25/2013 1:13:50 PM EDT
[#4]
Quick and dirty check of your alternator, without taking it out, is to start the car, and see if a small wrench or screw driver will stick to the side.  If it doesn't, the alternator isn't charging.
Link Posted: 7/25/2013 1:32:15 PM EDT
[#5]
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sounds like the alternator quit working

 

Link Posted: 7/25/2013 1:34:22 PM EDT
[#6]
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Quoted:
Quick and dirty check of your alternator, without taking it out, is to start the car, and see if a small wrench or screw driver will stick to the side.  If it doesn't, the alternator isn't charging.
View Quote



not always.
some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.

best bet, is to grab a volt meter and check voltage while car is running.
Link Posted: 7/25/2013 1:50:53 PM EDT
[#7]
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sounds like the alternator quit working

 



Check the tension of your belt.  A loose belt can cause an alternator to not work under a load.

Go by an auto parts store and have them check your alternator and battery (after you charge it over night.)
Link Posted: 7/25/2013 1:55:08 PM EDT
[#8]

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not always.

some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.



best bet, is to grab a volt meter and check voltage while car is running.
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Quoted:



Quoted:

Quick and dirty check of your alternator, without taking it out, is to start the car, and see if a small wrench or screw driver will stick to the side.  If it doesn't, the alternator isn't charging.






not always.

some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.



best bet, is to grab a volt meter and check voltage while car is running.
better get some jumper cables too, that battery is DEAD!  



 
Link Posted: 7/25/2013 4:22:45 PM EDT
[#9]
Discussion ForumsJump to Quoted PostQuote History
Quoted:



not always.
some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.

best bet, is to grab a volt meter and check voltage while car is running.
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quick and dirty check of your alternator, without taking it out, is to start the car, and see if a small wrench or screw driver will stick to the side.  If it doesn't, the alternator isn't charging.



not always.
some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.

best bet, is to grab a volt meter and check voltage while car is running.



Not every one has a VOM in their trunk (like me), or even their garage.  I was just offering up a quick and dirty check.  I in no way said it was precise.
Link Posted: 7/25/2013 4:29:44 PM EDT
[#10]

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Not every one has a VOM in their trunk (like me), or even their garage.  I was just offering up a quick and dirty check.  I in no way said it was precise.
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Quoted:



Quoted:


Quoted:

Quick and dirty check of your alternator, without taking it out, is to start the car, and see if a small wrench or screw driver will stick to the side.  If it doesn't, the alternator isn't charging.






not always.

some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.



best bet, is to grab a volt meter and check voltage while car is running.






Not every one has a VOM in their trunk (like me), or even their garage.  I was just offering up a quick and dirty check.  I in no way said it was precise.
If you can get the car started then disconnect the negative battery terminal. If the car still runs the alternator is good.  If it doesn't the alternator could be bad

 
Link Posted: 7/25/2013 4:43:58 PM EDT
[#11]
Discussion ForumsJump to Quoted PostQuote History
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Not every one has a VOM in their trunk (like me), or even their garage.  I was just offering up a quick and dirty check.  I in no way said it was precise.
View Quote



Your quick and dirty check should work to a point but on the other hand, a harbor freight voltmeter is $5 and plenty accurate for this.

Link Posted: 7/25/2013 4:51:53 PM EDT
[#12]
Discussion ForumsJump to Quoted PostQuote History
Quoted:



Not every one has a VOM in their trunk (like me), or even their garage.  I was just offering up a quick and dirty check.  I in no way said it was precise.
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Quick and dirty check of your alternator, without taking it out, is to start the car, and see if a small wrench or screw driver will stick to the side.  If it doesn't, the alternator isn't charging.



not always.
some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.

best bet, is to grab a volt meter and check voltage while car is running.



Not every one has a VOM in their trunk (like me), or even their garage.  I was just offering up a quick and dirty check.  I in no way said it was precise.


sorry if that came out sounding dick-head-ish i didn't mean it that way at all.   my apogees.  

Link Posted: 7/25/2013 4:52:15 PM EDT
[#13]
i'm with some that said a $5 cheap-o volt meter would do the trick for a fast self diagnostic test. or just run it by a parts store.  pretty much all of us test alternators for free with decent equipment.
the one we use costs $1900 and does a full test of the electrical system
Link Posted: 7/25/2013 4:54:11 PM EDT
[#14]
Link Posted: 7/25/2013 4:57:28 PM EDT
[#15]
Check cables and connections as well.  corrosion is a muther fucka,

cut open plenty of healthy looking cables that were just white powder on the inside.

But as quick as your symptoms came at you, I am going with battery/ alternator as well.
Link Posted: 7/25/2013 5:06:56 PM EDT
[#16]
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If you can get the car started then disconnect the negative battery terminal. If the car still runs the alternator is good.  If it doesn't the alternator could be bad  
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Quoted:
Quick and dirty check of your alternator, without taking it out, is to start the car, and see if a small wrench or screw driver will stick to the side.  If it doesn't, the alternator isn't charging.



not always.
some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.

best bet, is to grab a volt meter and check voltage while car is running.



Not every one has a VOM in their trunk (like me), or even their garage.  I was just offering up a quick and dirty check.  I in no way said it was precise.
If you can get the car started then disconnect the negative battery terminal. If the car still runs the alternator is good.  If it doesn't the alternator could be bad  


DO NOT DO THIS on modern computer - controlled cars! Use a voltmeter. Chance of frying engine computer!
Link Posted: 7/25/2013 5:10:52 PM EDT
[#17]
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Cheap check - take it to Pep Boys and have one of them check the battery and charging system for free.
View Quote


Not a bad idea as long as the OP charges the heck out of his battery first since he's probably running off of it and not the alternator.

To the OP-the heater/ac fan is probably the single largest consumer of electricity in your car.  Headlights and wipers are second, and window/mirror defrosters third.

Try not to run those while driving to Pep Boys, seriously.  Charge your battery and drive to the store with the windows open and the fan off.

With the events you describe, it is 90% likely that it's the alternator or the alternator belt, or alternator wiring.

Link Posted: 7/25/2013 5:11:58 PM EDT
[#18]
Check the ground cable from the negative terminal to the car frame.  Bet it is loose or has almost rusted through.
Link Posted: 7/25/2013 5:13:29 PM EDT
[#19]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


DO NOT DO THIS on modern computer - controlled cars! Use a voltmeter. Chance of frying engine computer!
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Quoted:
Quoted:

If you can get the car started then disconnect the negative battery terminal. If the car still runs the alternator is good.  If it doesn't the alternator could be bad  


DO NOT DO THIS on modern computer - controlled cars! Use a voltmeter. Chance of frying engine computer!


I'm with Oakenheart on this.  There's a thing called 'load dump' where you get a huge surge in voltage when the alternator is disconnected and it can cause expensive damage.  Some alternators and some cars are ok with this but it's a huge risk and there are better ways to get the answer.
Link Posted: 7/25/2013 5:19:58 PM EDT
[#20]
I think you must be dreaming.  You did say it was a Toyota.  Everything I have ever heard or read says they are the most wonderful cars ever made.  What could possibly go wrong with it?



Sounds like your alternator isn't charging.


Raffi
Link Posted: 7/25/2013 5:33:56 PM EDT
[#21]
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I think you must be dreaming.  You did say it was a Toyota.  Everything I have ever heard or read says they are the most wonderful cars ever made.  What could possibly go wrong with it?



Sounds like your alternator isn't charging.


Raffi
View Quote


Har dee Har Har...I gotta say though that this car has been great.  I mean it is a '97
Link Posted: 7/25/2013 5:47:04 PM EDT
[#22]


Discussion ForumsJump to Quoted PostQuote History
Quoted:
DO NOT DO THIS on modern computer - controlled cars! Use a voltmeter. Chance of frying engine computer!

View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:



Quoted:



Quoted:



Quoted:



Quoted:

Quick and dirty check of your alternator, without taking it out, is to start the car, and see if a small wrench or screw driver will stick to the side. If it doesn't, the alternator isn't charging.






not always.

some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.



best bet, is to grab a volt meter and check voltage while car is running.






Not every one has a VOM in their trunk (like me), or even their garage. I was just offering up a quick and dirty check. I in no way said it was precise.
If you can get the car started then disconnect the negative battery terminal. If the car still runs the alternator is good. If it doesn't the alternator could be bad




DO NOT DO THIS on modern computer - controlled cars! Use a voltmeter. Chance of frying engine computer!



I should have cautioned not to do it for more than just the time it takes to pull the lead.  it will die instanatly if the alternator is bad. If you pull it and make a full disconnect and it runs it is not the althernator so shut the vehicle down.
Link Posted: 7/25/2013 5:49:21 PM EDT
[#23]


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I'm with Oakenheart on this. There's a thing called 'load dump' where you get a huge surge in voltage when the alternator is disconnected and it can cause expensive damage. Some alternators and some cars are ok with this but it's a huge risk and there are better ways to get the answer.
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Quoted:



Quoted:



Quoted:



If you can get the car started then disconnect the negative battery terminal. If the car still runs the alternator is good. If it doesn't the alternator could be bad




DO NOT DO THIS on modern computer - controlled cars! Use a voltmeter. Chance of frying engine computer!





I'm with Oakenheart on this. There's a thing called 'load dump' where you get a huge surge in voltage when the alternator is disconnected and it can cause expensive damage. Some alternators and some cars are ok with this but it's a huge risk and there are better ways to get the answer.


the alternator will only put out its rated voltage if it is healthy and will only produce current as required.  The battery will filter out the harmonics of the produced power which you want but if it is a short duration you will not damage anything.  
Link Posted: 7/25/2013 5:52:19 PM EDT
[#24]


Discussion ForumsJump to Quoted PostQuote History
Quoted:
DO NOT DO THIS on modern computer - controlled cars! Use a voltmeter. Chance of frying engine computer!

View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:



Quoted:



Quoted:



Quoted:



Quoted:

Quick and dirty check of your alternator, without taking it out, is to start the car, and see if a small wrench or screw driver will stick to the side. If it doesn't, the alternator isn't charging.






not always.

some cars have shielded alternator housings to keep electromagnetic fields from tripping other things out.



best bet, is to grab a volt meter and check voltage while car is running.






Not every one has a VOM in their trunk (like me), or even their garage. I was just offering up a quick and dirty check. I in no way said it was precise.
If you can get the car started then disconnect the negative battery terminal. If the car still runs the alternator is good. If it doesn't the alternator could be bad




DO NOT DO THIS on modern computer - controlled cars! Use a voltmeter. Chance of frying engine computer!



also if the battery has enough charge to start the engine you may still read a voltage that is in tolerance (although on the low end) unless you run it till the battery is almost incapable of maintaining sufficient voltage to keep the car running
Link Posted: 7/25/2013 6:07:48 PM EDT
[#25]
Charging system issue.

Running hot by any chance?

I was stopped at a light once, hear a bang and both the brake and charge lights come on. Was working at the time so I decided to swing by a buddy's shop to take a look at it. On the way there it started overheating. Made it there with the temp gauge 3/4 of the way up.
Pop the hood and myself, a buddy and a couple of his coworkers are standing there staring at the engine trying to figure out WTF was going on.

After about 5 minutes one of them reaches under the hood and spins the engine fan.
Alternator belt had broken. Same belt runs the water pump.

40+ years of mechanical knowledge stumped briefly.
10 minutes later a new belt is installed and I am on down the road.
Link Posted: 7/25/2013 6:29:41 PM EDT
[#26]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


the alternator will only put out its rated voltage if it is healthy and will only produce current as required.  The battery will filter out the harmonics of the produced power which you want but if it is a short duration you will not damage anything.  
View Quote


That is true when operating normally, but when you remove the load wire all of the stored energy in the magnetic field turns into a spike and it can zap lots of stuff.  Unless the alternator is designed to clamp that spike it can make a 100 volt or higher spike on its output.  The regulator doesn't control this because it can't.



Link Posted: 7/25/2013 8:01:02 PM EDT
[#27]
any auto parts place can test your alternator in 2 minutes



my bad wire was from the regulator to the junction box - took a bit of tracing to find where it was bad.


Link Posted: 7/25/2013 8:08:13 PM EDT
[#28]
First off, how old is the battery in the car ?

Take a voltmeter and test the voltage of the battery, if it is anything less that 12 volts it's shot.

I would start with looking at the battery first.
Link Posted: 7/26/2013 12:47:31 AM EDT
[#29]
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First off, how old is the battery in the car ?

Take a voltmeter and test the voltage of the battery, if it is anything less that 12 volts it's shot.

I would start with looking at the battery first.
View Quote



Unless it's discharged due to alternator not charging....  Fire up the car, rev it to 2500 or so, and check voltage at battery. If the alt is working, it should be around 14V, not working it will read 13V or less, probably less than 12V.  A fully charged, good battery will read close to, or over 13V. Because a lead-acid cell will be 2.2V, fully charged. 6 x 2.2 = 13.2

Also, if a fully charged battery drops below 9V while cranking the engine, it is toast.....
Link Posted: 7/26/2013 1:03:48 AM EDT
[#30]
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Quoted:
alternator not charging battery - car running off battery and it's dead



charge battery - check alternator  - if it's good check ALL your wiring


just had the same issue, changed my battery x2 and alternator x2 - ended up being one corroded wire - bypassed that and all is good now
View Quote



This!

My truck at times will have the battery light come on, the air bag light and ABS light. Think about it?

The same lights as when you start the engine!

It's either a bad connection or the battery is crapping out.

My money is on bad connection at the battery.

I say this because mine has done this maybe 3 or 4 times in the past year and it's the same battery.

And it only happens at night on a lonely stretch of road. At first I freaked out and thought "I'm in the twilight zone". And then thinking it is winter time and things shrink and contract (bad connection) then it also happened several months later when it was warmer.

The last two times it has been while parked on a slight (very slight) down hill parking spot.

Still don't really know what it is. Could be a connection or still possibly a bad battery and when it gets in a certain position it goes all funky.
Link Posted: 7/26/2013 5:05:25 AM EDT
[#31]

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Quoted:
That is true when operating normally, but when you remove the load wire all of the stored energy in the magnetic field turns into a spike and it can zap lots of stuff.  Unless the alternator is designed to clamp that spike it can make a 100 volt or higher spike on its output.  The regulator doesn't control this because it can't.
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Quoted:



Quoted:





the alternator will only put out its rated voltage if it is healthy and will only produce current as required.  The battery will filter out the harmonics of the produced power which you want but if it is a short duration you will not damage anything.  




That is true when operating normally, but when you remove the load wire all of the stored energy in the magnetic field turns into a spike and it can zap lots of stuff.  Unless the alternator is designed to clamp that spike it can make a 100 volt or higher spike on its output.  The regulator doesn't control this because it can't.
Except that lifting a battery cable doesn't unload the alternator except the charging current.  The alternator would still be carrying a load (supplying current) and therefore you don't get a the spike you fear.

 
Link Posted: 7/26/2013 7:23:37 AM EDT
[#32]
Discussion ForumsJump to Quoted PostQuote History
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]I should have cautioned not to do it for more than just the time it takes to pull the lead[/span][/span].  it will die instantly if the alternator is bad. If you pull it and make a full disconnect and it runs it is not the alternator so shut the vehicle down.
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The act of disconnecting the neg cable while the engine is running is all the time it will take the voltage spike to do it's damage; you're not faster than electricity.

Extremely poor advice.  Never disconnect the batteries of a running vehicle and especially any newer vehicle with electronics.  This used to be the standard advice back before the '80's (or earlier) when cars had DC generators, not the120 three phase AC rectified to 12 vdc alternators that almost all cars run now.

More reading, same subject:

http://www.troubleshooters.com/dont_disconnect_battery.htm

http://askville.amazon.com/battery-disconnected-car-running-shut/AnswerViewer.do?requestId=70241207

http://wiki.answers.com/Q/What_happens_if_you_disconnect_the_battery_while_the_car_is_still_running

http://www.supercharge.com.au/battery-myths


As several people above have said:  Get a cheap ($5-$10) voltmeter and check the running voltage:  +13 vdc, the alternator is good.  ~12.5 vdc or less, the alternator is shot.  If the battery itself, after being fully charged, is less than 12.5 vdc or so, it's probably shot.

Simple, cheap, easy and effective.  Plus: absolutely no chance of frying the vehicle's electronics or wiring like disconnecting the battery can do.

Good luck!!!
Link Posted: 7/26/2013 8:15:35 AM EDT
[#33]
How many volts on the battery when at idle?
Link Posted: 7/26/2013 9:43:44 AM EDT
[#34]
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How many volts on the battery when at idle?
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With a good alternator, around 13.5 to 14 vdc.  It should be obvious from EO, ES, then idle.  

Engine Off:  12.5-12.6 vdc for a good battery

Engine Start:  +11 vdc.  If it goes much lower, then your battery is probably toast (as stated above).

Idle: 13.5-14 vdc.  Some diesels have glow plugs that pull +60 amps, so the alternator may take a moment or two to register this voltage after the GPs switch off.

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