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Old 03-03-2008, 10:33 AM   #1
ruthmann88
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electrical problem

Hey guys I have a serious electrical problem I can't fix.
Bought a new battery, problem still persists. The car would never die while driving, and the battery would only die if left connected overnight. So disconnecting the battery when i wasnt driving was my cheap fix.

Now the battery's dieing while i'm driving so I am assuming my alternator has given up.

Now prior to my alternator giving up I hooked up a voltage meter in between the positive terminal of the battery and the car. I pulled every fuse and relay and found no drop in voltage. Therefore I couldn't find the result of the parasite drain.

Could my alternator have been faulty for a while and have been killing my car while sitting over night; but yet still charge my battery while the car was running? This is all I can come up with. I don't see what other electrical component in which I didnt pull the fuse for would cause this.

Thanks.
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Old 03-03-2008, 12:25 PM   #2
everlast
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Post some stats you find with your meter: how many volts do you read with the car off, and how many with the car running. Can your meter show amps (current)? If so, measure the current coming from your battery. Ask if you don't know how, I can give you a step by step.

It could be there was a drain killing you battery, and now your alt. is fried from charging your battery from dead so many times. That happens a lot; the alt. is not meant to charge a dead battery.
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Old 03-03-2008, 02:15 PM   #3
ruthmann88
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i gotta get my hands on a new meter mine broke. I'll post the stats up tommorow, ty.
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Old 03-04-2008, 11:04 AM   #4
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Starters do crazy things too, but this does sound like an alternator issue. Be sure to search the forums, I am sure this was discussed within the year.
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Old 03-04-2008, 07:11 PM   #5
slimjim
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i know it sounds stupid, but is ur alternator belt loose? when u wiggle it, you shouldnt have too much play. the exact same thing happen to a friend of mine.

ya, first thigs first check oming fr the battery should be around 14v.
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Old 03-04-2008, 10:12 PM   #6
InfiniteDice
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ok..

K man, possible solution.

Get a volt meter and hook it in the lighter plug or wherever you should have battery voltage.

Start the car it should go to 13 volts, or near to it definitely over 12 volts.

If not rev the engine over 3k. Make sure the engine is at least out of the blue on the temp gauge.

The voltage should now rise to roughly 13 volts.

This is testing the alternator, the small + lead to the alternator tells it to charge the field and start the charge. If it charges after revving you should check that lead, make sure it's giving 12v (battery voltage) on run. If it is giving battery voltage on 'run' then you have an alternator field issue and you'll need a rebuilt or new one.

Later.
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Old 03-04-2008, 10:17 PM   #7
InfiniteDice
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in addition.

The reason the alternator kicks in automatically after a 3k rev, is that at that speed it builds enough internal charge to kick itself on. If after revving to 3k it doesn't turn on... the alternator internal board needs to be changed, probably cheaper just to get a good used one or a rebuilt one.

later.
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Old 03-05-2008, 10:36 AM   #8
ruthmann88
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Hey everything fixed. It was the alternator. Got it rebuilt. I didn't know that a faulty alternator could actually cause a parasite drain. Thanks for everyones input.
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Old 03-05-2008, 02:29 PM   #9
InfiniteDice
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cool glad u worked it out.

Well if the alternator needs current to activate the field, yet at the same time isn't feeding the system a charge, I suppose what you get is a net loss, and the resultant battery drain.

Later man,

Mike.
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Old 03-06-2008, 12:23 AM   #10
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It won't generally drain the battery when the car is off tho, so if your car goes dead again you still may have a drain.
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Old 03-10-2008, 10:14 AM   #11
WillieE30
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Bad Diode in Alt can cause drain.....good fix and diagnosis.......Bill

P.S....A good tool to have in your tool box is a clamp on current meter for D.C....can be expensive but well worth it for drains......cheers

Last edited by WillieE30; 03-10-2008 at 10:17 AM.
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