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Alternator test?


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Posted

I've heard that if you disconnect your battery while the car is running, and if the car dies, you have a bad alternator. Is there any truth in this?

Posted

I'm not sure how are car's are wired....but it seems valid. You should just test your alternator with a voltimeter...it would be alot easier as well IMO.

Posted

Don't take the battery cables off with the car running, or you might need a new alt quicker.

Posted

Um. Correct me if I'm wrong, but wouldn't taking a battery cable off suddenly make the car no longer have a complete circuit and make it die anyway? :shrug:

Posted

I think you would only break the circut if you disconnected the ground...I think

Posted
Um. Correct me if I'm wrong, but wouldn't taking a battery cable off suddenly make the car no longer have a complete circuit and make it die anyway? :shrug:

 

That's what I was thinking as well, but I wasn't sure

Posted

WELL, I tried it, and the car ran fine without the battery, the voltage spiked a bit but other than that everything was fine. EXCEPT, when I shut off the car, re-attached the cables, started it up again, I tried turning on the A/C before I unplugged the battery, and the car died instantly when I unplugged the battery. ...do I have a bad alternator? or should that have happened?

Posted

I'm sure when you switched on the compressor, it put a strain on the alternator and caused the coils to fire at a voltage lower than required, hence the motor quitting. If you had the battery connected, it would have provided the extra boost in voltage the system needed at that moment.

 

You have a 3.1, (ha, I looked at your cardomain page :lol: ) removing the alt to have it checked out isn't that big a deal (be thankful you don't have a 3.4...)

Posted

You have a 3.1, (ha, I looked at your cardomain page :lol: )

...what's that supposed to mean :?

 

Edit: J/k :lol:

Posted

The alt is easy to remove. Take it easy.

 

Edit: Nice car BTW. Rarely does an engine bay stay that clean outside of a showroom floor.

Posted

You have a 3.1, (ha, I looked at your cardomain page :lol: )

...what's that supposed to mean :?

 

Edit: J/k :lol:

I wasn't laughing at your car. Most people won't click on a link provided to see what the poster's car is about. I actually did click the link, so I "LOL'd" about it :wink: .

 

Back to the alternator, once you get it out, spin the pulley and see if it makes any odd noises. If you can hear any kind of squeaking, chances are your alternator's fried (or at least on its last legs.) That alternator in particular (CS-130) has a poorly designed case and sealed bearings that are too small. The poor design doesn't allow for proper heat dissipation, and this cooks the undersized bearings (and sometimes the voltage regulator.) The squeaking is a dead giveaway to eminent failure...

Posted

I just had the alternator tested, and it checked out just fine. There was a very slight squeaking noise though, yet very faint. :willynilly: What's going on?? :willynilly:

Posted

The reason I tested the alternator in the first place is i'm losing power... and I don't know why...

Posted

losing power, hmm, ur battery could be bad, or a bad ground, check the grounds from the neg bat terminal and the ground to the block

Posted

Battery is good, terminals are clean, and the car seems to lose power the worst when the AC is on. The power loss is gradual, too.

Posted

It could be a draw coming from the door electronics sucking power. my pass. seatbelt had a draw and I just unplugged the clip off it. power door locks have a short too but they still work one way.

 

I want to get new door wiring harness. w-body cars have issues there. I guess as you open and close the door thousands of times some wires can break in there.

 

The starter has a fusible link that you can wireloom.

 

 

If you touch a solenoid or something and it is hot to the touch, that should give you tears of joy because you are getting close to finding the draw.

 

so keep it on the charger and go around the car you might get lucky.

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