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So went to the auto parts store, alternator AND battery test good. Guy at the counter said probably a short caused the burnt wire at the positive terminal on the alt
Possible, but doesn't explain why it's putting out 15-16 volts. Did they tell you a voltage or just that it's good? They could have just hooked up a battery tester that only tells you good/bad. Definitely sounds like the alternator is still problem here.
 

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Captain TMI
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Yes, and load test on the battery would show it to fail. Voltage would appear fine, but hold a voltmeter on the battery terminals while someone tried to crank the engine and you'll see it drop to ridiculous lows.

Voltage that is too high will overheat the battery, and cause it to fail. It might show voltage, but it has no capacity for current.

What happened to you is that you purchased an alternator with a bad voltage regulator. It's a shame, but true. I typically ask people to locate a local rebuilder for electrical parts because small businesses can't afford to install parts that fail for their customers like big chain stores can. Big chains can afford to replace parts on lifetime warranty over and over again, you pay their cost for probably 6 rebuilds or more when you purchase one lifetime alternator.
 

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X2, a 'short' would LOWER the volts as they are not all running down the wire, the short circumventing some of it offline.

Most people working in a parts store wouldn't know a short or an open if it smacked them right between the eyes.

The overvolt condition melted the connector along with corrosion if the plastic cap was gone, the corrosion then eats into the connection to remove enough active crossover material, and then the connection begins to arc and melt.

Tear out the metal strip conductor inside that big plastic boss that sticks out, the conductor as supplied and engineered by Ford is laughably small there. More substandard electrical engineering that sells millions of parts due to seemingly incompetent design, that is really designed to create new parts sales streams, it's not incompetent at all. Back in the '60s a 35 amp alt output post would have a cross section 50% larger or more than the 110 amp one does now.
 

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Discussion Starter #24
The alternator was tested for output voltages. highest ever during the test was 15.3. This car has a bunch of other electrical issues as well, so I am not ruling out anything.
 

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If the alternator was tested for 15.3 volts out of the car then it's the alternator failing. What other electrical problems do you have? They may not be related but someone might know a fix
 

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That's OK and within normal Focus running ranges. They charge a bit higher than textbook numbers are. Up to 15 is fine and all day long. The regulator sets at 14.5 as normal.
 

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Discussion Starter #28
Thanks AMC, so if the Alt and battery are good, that leaves me with some sort of electrical issue causing a short, or something to burn the positive terminal on the alt.... I really have no idea what to do with electrical systems, I can change any part in the world though! haha
 

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Discussion Starter #29
one thing to note as well, the positive terminal on my battery corrodes like no other, maybe that has something to do with it?
 

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Old Phart
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Unusual corrosion like that is a sign of acid leakage from the battery.

Could have been made worse or even caused by overcharging in the past.

If yours is a sealed battery, it's life will be reduced significantly as acid level drops in that cell, beyond the hassle of constant cleaning/protecting the terminal (baking soda neutralization, coating terminal/connections with grease).

Bad enough, it can destroy terminals/wiring to cost a LOT in repairs, not counting damage to other items where it drips.
 

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Discussion Starter #31
thanks sailor! Turns out the battery was bad, the slow charge did not help. got a new battery, hooked everything back up, and its running now. getting 14.9 volts now to the battery.
 

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Old Phart
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Keep an eye on that, voltage should drop lower as the battery comes to full charge - even new.

Sounds better for sure!
 
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