broken alternator? help!

Hi, I have a 1986 Mazda 323 (fuel injected). I was driving back home the other day when the electronics started to go. The radio started
cutting in and out, and eventually faded to static. Next the tachometer would slowly drop down toward 0, but then catch again (just the gauge - the engine was running fine). Finally the engine started hiccuping (fuel injectors) and immediately everything died and I had to coast off the road. At this point everything was completely dead (no hazard flashers, even) and I had it towed home. Based on my very limited knowledge of cars, I guessed the alternator had gone, as the same thing happened to me in another car. I recharged my battery at home and it fired right up. My question is this: how can I tell what the problem is now? Assuming the alternator is broken, how long could my car run off of just the battery alone? Assuming it wasn't the alternator, what else might have caused this? Help! Many thanks!
~matt
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On 21 Dec 2005 21:47:36 -0800, snipped-for-privacy@gmail.com wrote:

Your alternator croaked. You can't go far without one, as the battery is there mainly for starting the car. The continuous electricity to keep the car going comes from the alternator. Yours is broken. The battery will drain quickly, especially quickly if you put your lights on.
You can't do anything about this except repair/replace the alternator. There is no work-around, nothing else in the car that generates the required electricity.
Lg
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Yes the alternator needs to be replaced or rebuilt. You should be able to get a replacement fairly cheap and replacing it yourself shouldn't be a problem.
http://www.carforums.net/ Auto Forums
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Those alternators come out the bottom. Can't get them out from the top. Pretty tough to do without a lift.
--

Dave in Columbus

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wrote:

Just another moron spamming his web site at every opportunity. Bob
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wrote:

Especially considering the fact that an 80 amp fuse exists between the battery and the alternator I think it's premature to condemn the alternator. It may well be bad but it's better to check the basics now instead of throwing an alternator at the problem and then thinking "gee, it's still not charging, what's up with that?" Bob
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Measure the voltage with the engine running. It should be about 14 volts. If it is below 12.5 volts the alternator is dead.
snipped-for-privacy@gmail.com wrote:

--
Mike Walsh
West Palm Beach, Florida, U.S.A.
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Mike Walsh ( snipped-for-privacy@netrox.net) writes:

Start the engine and put the voltmeter leads on the two terminals of the battery. What you see is the "charging voltage". The alternator charges the battery as well as firing the spark plugs and illuminating the lights and every thing else on the car. It's what keeps you from having to have a very long extension cord to use the car. The battery can't fire the sparkplugs for very long.
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snipped-for-privacy@gmail.com wrote:

To answer your question, I have heard a prediction of 20" to a half hour before the voltage would drop below what was needed to operate the electronics. The fact that you were able to get it down to where not even the flashers would operate is puzzling.
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I had a new 84 Fiero that had lots of problems with the charging system, largely due to incompetent GM mechanics. (Pully system incorrectly reinstalled after warranty work, etc)
When the voltmeter on the dash dropped below the magic level, I had about 15-20 minutes driving time in the daylight. With the headlights on, it would probably have been considerably less.. I didnt tend to take it out much at night, obviously, until my son and I pulled the engine and repaired/reengineered this turkey.
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Talking about re-engineering turkeys: had an '85 Seville to whip me(temporarily, but just the same...). Battery went dead slowly w/wife driving. Got it to me. Drove it & NO alternator warning lite glowing--no gauges, IIRC. Checked voltage at batt terminals & sure enough, voltage output was equal to battery voltage, with batt weakened or fully charged. Replaced alternator. Same problem. Turned out, I just intuitively(or accidentally?)watched dash lites as I cycled key on/off--no alternator lite glowed. Pulled dash, replaced blown indicator bulb, both alternators charged perfectly. Reason? Reckon it had to be the field coils in the alternator were energized thru a series-installed indicator bulb circuit. Don't we love that engineering? A 13-cent bulb behind a $50-dash-pull controlling output of a $150-alternator !!! s
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sdlomi2 wrote:

Bosch is the same way, FWIW.
nate
--
replace "fly" with "com" to reply.
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