What happens when and alternator going out?

[SilverEvo8owner]

Wow i really screwed up the title on this...

Anyways

 

Reason why I'm asking is that on the way back from Dark Knight this evening, my car started making a weird noise only around 1200-1500 rpms. I can almost compare it to a hydraulic pump kinda sound. I got back from the movies and looked all around under the hood but I could find nothing. So I took the car out again and did a pull at waste gate pressure, pulled over, and shut the car down to look if I could see and smoke or anything; there was nothing. When I started it again car it struggled to turn over but started. Got back to my appartment and there was a bit of a burning smell but no smoke. Turned the car off, tried to start again and it clicked but would not turn over.

 

So does this sound like an alternator issue? I am assuming so because it would only make sense the car is dead from running on battery power instead of the alternator. The car has 83k on it and has never had an electrical problem.

 

Do these things make noises when they go out? Do they fail this sudden?

 

Thanks

Chris

[wnaplay1647545503]

They tend to fail suddenly. You can charge your battery and drive to advance auto and have them test it. I dont know if they can test it off the car or not. Just dont drive very far and dont turn anything on. I think you might be able to pull one of your battery cables off and the alternator should keep it going. Thats an old school test. I havent had a alternator go out on me(knock on wood) in about 15 years. So I am just trying to think back how to test a failed alternator.

[Mensan]

Take it to Autozone and they will test it for you. A failed alternator will allow your electrical system to drain the battery while you are driving.

[SilverEvo8owner]

thx guys

 

im gonna try to get it started and checked tomorrow.

[2 Sweet]

Like stated above.....if it's dying, you'll see your volt gauge gradually fall to the point where your lights begin to dim and you're just trying to get home before your car completely dies. It's happened to me a few times

 

I didn't hear any irregular noises though

[Guest mrhobbz]

Get a multimeter touch the contacts to the battery poles at idle - should be a little higher than 12, then at around 2k rpm. If its higher than 12 at those voltages alternator is probably good (maybe failing under load though) You'll know when it goes dead, volt meter will drop, lights dim, gauges shut off, power steering shuts off, car shuts off.

[shm21284]

Also, the bearings can go bad, maybe this caused the humming noise? I had that happen once... bearings went bad and overheated the electronics, fried the alternator.

[SilverEvo8owner]

car won't run without the battery connected so it looks like it is definately the alternator...

thanks for the help

[Guest Hal]

Get a multimeter touch the contacts to the battery poles at idle - should be a little higher than 12, then at around 2k rpm. If its higher than 12 at those voltages alternator is probably good (maybe failing under load though) You'll know when it goes dead, volt meter will drop, lights dim, gauges shut off, power steering shuts off, car shuts off.

Wrong. Please don't advise people of test procedures you are not familiar with.

 

car won't run without the battery connected so it looks like it is definately the alternator...

thanks for the help

Wrong.

 

The alternator and the battery need each other. If you are coming to dragway 42, I will bring my multimeter and check it out for you.

[Guest 78novaman]

Wrong. Please don't advise people of test procedures you are not familiar with.

 

 

Wrong.

 

The alternator and the battery need each other. If you are coming to dragway 42, I will bring my multimeter and check it out for you.

 

 

Actually you are wrong.

 

You scare me that you work on cars for a living. All an alternator needs to run is an electric field sense input, which the unit can make itself, or have you never heard of a one wire alternator before?

 

The bearings are an easy check. Take the belt loose and spin the alternator by hand if it makes a bad grinding noise and you can feel it bingo bad bearings. If it is quiet it could just be the brushes.

 

Alternators do not always suddenly die, the brushes can become corroded and reduce performance to the point the unit can no longer produce a high enough voltage. It is easy to fix for about $15 and some simple hand tools.

 

 

If you have a healthy alternator, the car running, and remove the battery cable it will definitely keep running, otherwise you would have a dead battery quite quickly. Why do you think you can jump start a dead battery and then proceed to remove the jumper cables?

 

 

Also a healthy alternator should be outputting around 14.4V after start up and at least 13.5V ~2000rpm. Nominal battery voltage is 12.2V-12.5V thus the alternator must produce a higher voltage or the battery will become drained over time.

[Guest mrhobbz]

Wrong. Please don't advise people of test procedures you are not familiar with.

 

 

Wrong.

 

The alternator and the battery need each other. If you are coming to dragway 42, I will bring my multimeter and check it out for you.

 

 

 

Wrong? how? Kthx.

[Guest mrhobbz]

Actually you are wrong.

 

You scare me that you work on cars for a living. All an alternator needs to run is an electric field sense input, which the unit can make itself, or have you never heard of a one wire alternator before?

 

The bearings are an easy check. Take the belt loose and spin the alternator by hand if it makes a bad grinding noise and you can feel it bingo bad bearings. If it is quiet it could just be the brushes.

 

Alternators do not always suddenly die, the brushes can become corroded and reduce performance to the point the unit can no longer produce a high enough voltage. It is easy to fix for about $15 and some simple hand tools.

 

 

If you have a healthy alternator, the car running, and remove the battery cable it will definitely keep running, otherwise you would have a dead battery quite quickly. Why do you think you can jump start a dead battery and then proceed to remove the jumper cables?

 

 

Also a healthy alternator should be outputting around 14.4V after start up and at least 13.5V ~2000rpm. Nominal battery voltage is 12.2V-12.5V thus the alternator must produce a higher voltage or the battery will become drained over time.

 

 

+1

[Guest Hal]

Hobbz, you highlighted where you were wrong. 12v is too low. Don't say it should charge at that.

 

78novaidiotfagretard. You are wrong. I'm not getting into here at work. I don't work on cars for a living either. Where do you get your info?

[Guest mrhobbz]

Hobbz, you highlighted where you were wrong. 12v is too low. Don't say it should charge at that.

 

78novaidiotfagretard. You are wrong. I'm not getting into here at work. I don't work on cars for a living either. Where do you get your info?

 

Where did i say 12? I said higher than 12. Read what I posted retard.

[Guest Hal]

Get a multimeter touch the contacts to the battery poles at idle - should be a little higher than 12, then at around 2k rpm. If its higher than 12 at those voltages alternator is probably good (maybe failing under load though) You'll know when it goes dead, volt meter will drop, lights dim, gauges shut off, power steering shuts off, car shuts off.

Higher than 12 is 12.1, 12.2, 12.3. Higher than 12 is 15, 16, 17, 18.

 

You're a complete retard.

[Guest Hal]

For 78dipshit, if you want to try to diag dead alternators the way you can with a 60's car, go ahead. If you want to kil the diodes right away, continue doing that.

 

Go read an electrical diagnosis book. I can tell you I have and will post even more as to why you fail when I get home.

[Guest 78novaman]

Damn I left for a couple of days and I had insults!

 

For 78dipshit, if you want to try to diag dead alternators the way you can with a 60's car, go ahead. If you want to kil the diodes right away, continue doing that.

 

Go read an electrical diagnosis book. I can tell you I have and will post even more as to why you fail when I get home.[/Quote]

 

The pic in your sig infers that you work at a shop. I guess you're just too dumb to work on your own vehicles.

 

I work on electronics for a living and if you want me to bust out an oscilloscope (overkill) to diagnose I can do that.

 

My "60's" methods of diagnosis fixed the alternator on our 1997 Cougar. Only cost me $14.98 and about an hour or two for a new set of brushes/cleaning. That's a whole hell of a lot better than $150 for a new one (stock 130A unit) or $200+ to take it to a shop.

 

Do you even know how those portable analyzers work? Guess what, all it does is put a high amp load on your alternator and checks the voltage to be sure it's above 12.5V. I'll even enlighten you that it determines the RPM of the engine from measuring the frequency of the ripple voltage. I can do the same test with a $10 harbor freight multimeter or a 60's analog sweep gauge if you wish.

 

Burned out diodes.....you crack me up. His evo couldn't pull 100A with the A/C on and the stereo blaring.

[Guest Hal]

Go burn out all the diodes you want, you are a failure of a tech if you think disconnecting the battery is the correct way to diag. an alternator. You need to look into more ways to kill diodes too.

 

I never said I would use a tester dipshit. I said I would bring my multimeter out and check it. You're the reason I don't work in shops anymore. Too many retarded techs that think they know everything. The flat rate way is usually not the best way. Where do you work? I want to know so I can tell everyone I meet, to avoid that place.

 

You're a complete retard and need to go back to school if you think the things you type are even close to correct.

 

Do I need to go grab one of my electrical diagnosis books? I'll go quote the correct ways to check an alternator if you need that.

 

If I were you, I would sell all my tools and go be a janitor.

 

PS. I am aware of how testers work. I have to answer questions about tools all day long. You know why? 'Cause I know that the fuck I'm talking about.

[Guest 614Streets]

[Guest Hal]

Get out of here, you don't know anything about electrical work

[Guest 78novaman]

LOL I'm not a shop tech. I work on circuit boards and testing units.

 

 

 

I love the part where you try to call me out but I have given facts and figures where you just say I'm wrong with no evidence to back that claim up, other than you say you've read some book.

[Guest Hal]

LOL I'm not a shop tech. I work on circuit boards and testing units.

 

 

 

I love the part where you try to call me out but I have given facts and figures where you just say I'm wrong with no evidence to back that claim up, other than you say you've read some book.

Fact, you will burn out diodes.

Fact, that is not a proper way to diagnose failure of an alternator.

Fact, you are an idiot.

Fact, I have a life that does not afford me the time to dig through my books for the sake of proving you wrong.

 

Fact, you are a complete waste of life. Go off yourself moron.

[Guest 614Streets]

Warning!

 

Some people tell you that you can check your alternator by disconnecting it from the battery to see if the alternator can produce enough current to keep the engine running. BAD IDEA! Disconnecting the battery will subject the voltage regulator (and computer and audio equipment...) to significant voltage spikes which may cause an otherwise good alternator to fail. Even if there were no damaging spikes, this test would not indicate whether or not the alternator was good because the engine will easily run with a weak or failing alternator.

 

 

HAL wins?

[Guest Hal]

Will's my friend now. Not to mention, a better tech than I.

[Guest 614Streets]

Will's my friend now. Not to mention, a better tech than I.

 

STFU.