Alternator/Voltage Regulator bad???
08-30-2002, 07:47 PM
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Alternator/Voltage Regulator bad???
I've read most of the archived posts and still can't seem to find one specific to my problem! Battery died last week (89 3.2L Carrera) for no known reason, replaced it with a fresh DieHard. Initial assumption was that I had an old battery - easy fix. Not so fast...
Drive to work (short trip) two days later in the rain and the car doesn't even have enough V to turn the starter by lunchtime. I get a jump and head to Sears where they do the battery tester - it says BAD BATTERY - so we replace it (for free w/ 18 month warranty). I'm starting to think Voltage Regulator frying batteries at this point. I get the old Digital Voltmeter out and start my testing (the same day I have the second battery installed).
Battery reads 12.2V.
Reads 13.8V at idle, no accessories on.
Reads 13.9V at 2K with nothing on.
Reads 13.4V at 2K with brights, radio, and rear defroster on.
These all look pretty normal to me - maybe I really did have a bad lot of batteries. Well, this morning I go out to double check the readings - battery at 11.9 w/ engine off, idle at 13.7, looking good, then I see the voltage drop to 12.2, 11.8 while still at idle.
Oh boy, alternator is erratic. The weird thing is, when the alternator stops producing juice, the engine tone changes slightly. With the DV connected, I noticed while the engine made its usual whining/whirring sound, the readings were normal, this whining sound goes away and no charge coming from the alternator! The idle speed stays constant around 950, its just the sound that differs.
I'm at a loss here, fellas, help me out!
It cycled a bit between the two but spent more time at idle w/o this noise - therefore draining the battery slowly. Anyone have any ideas? Time to rebuild the alternator? New voltage regulator?? If it was the VR, would that only produce a high current to over-charge/boil the battery, or can it cause intermittent alternator operation? I could buy a battery charger but that isn't really fixing anything!
BTW- The Idiot Light only lights up when I go to "start" now and then goes out as soon as the engine reaches idle - never to return while running. I thought it used to light after the first click, with the oil press. light?? Damn.
Put a chip in about a month ago (probably unrelated but I'll throw it out there), which I may switch today just to be sure.
Thanks for any advice!
Drive to work (short trip) two days later in the rain and the car doesn't even have enough V to turn the starter by lunchtime. I get a jump and head to Sears where they do the battery tester - it says BAD BATTERY - so we replace it (for free w/ 18 month warranty). I'm starting to think Voltage Regulator frying batteries at this point. I get the old Digital Voltmeter out and start my testing (the same day I have the second battery installed).
Battery reads 12.2V.
Reads 13.8V at idle, no accessories on.
Reads 13.9V at 2K with nothing on.
Reads 13.4V at 2K with brights, radio, and rear defroster on.
These all look pretty normal to me - maybe I really did have a bad lot of batteries. Well, this morning I go out to double check the readings - battery at 11.9 w/ engine off, idle at 13.7, looking good, then I see the voltage drop to 12.2, 11.8 while still at idle.
Oh boy, alternator is erratic. The weird thing is, when the alternator stops producing juice, the engine tone changes slightly. With the DV connected, I noticed while the engine made its usual whining/whirring sound, the readings were normal, this whining sound goes away and no charge coming from the alternator! The idle speed stays constant around 950, its just the sound that differs.
I'm at a loss here, fellas, help me out!
It cycled a bit between the two but spent more time at idle w/o this noise - therefore draining the battery slowly. Anyone have any ideas? Time to rebuild the alternator? New voltage regulator?? If it was the VR, would that only produce a high current to over-charge/boil the battery, or can it cause intermittent alternator operation? I could buy a battery charger but that isn't really fixing anything!
BTW- The Idiot Light only lights up when I go to "start" now and then goes out as soon as the engine reaches idle - never to return while running. I thought it used to light after the first click, with the oil press. light?? Damn.
Put a chip in about a month ago (probably unrelated but I'll throw it out there), which I may switch today just to be sure.
Thanks for any advice!
08-31-2002, 11:23 AM
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*Im interested in the answer to this as well. My 85 Carerra's battery boiled over... didnt explode but it put off this really bad egg smell... I guess it was the sulphuric acid.. I was lucky. I had it towed to a garage and the battery tested out same as yours. Didnt seem that the VR was off. I take the car home after no charge , no repair and the same thing happened.
Any help with previous experiences would be helpful....
Thanks DSul
Any help with previous experiences would be helpful....
Thanks DSul
