Alternator keeps going out...

[YungICY]

My 3rd alternator in a little over a year just went out again. The first one was due to a bad voltage regulator. The second was actually my bad and it had a loose wire. And this one is now the third. All the wires seems fine and are tightly connected. It has an external regulator. This is on an 85 2.3l. What should I be looking for?





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[YungICY]

I'm probably just taking a shot in the dark on this one but I think I might have narrowed it down to a bad regulator.



The battery seems to be somewhat charging while driving (lights get brighter with acceleration), I don't have an amp light come on at all and all the connections and wires for the alternator appear to be in good shape.



Any thoughts?


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[YungICY]

I think I may have fixed it. I appears to have just been a loose belt. I didn't think of that first because its always squealed in high rpms and it wasn't acting any different. But I thought, just for the hell of it lets tighten that up.


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[Kowboy]

Glad we could help, LOL. I've seen them go out when the belt is put on wrong as well. In that case, the alternator was spinning in reverse. Killed the alternator.

 

[RonD]

Lights dimming at 750rpm idle is not "normal", just mentioning that because I often see people saying it is, lol.
No car maker would spec an alternator that didn't have enough output at idle to run factory equipment.

Just for future use a $15 volt/ohm meter can save you hundreds of dollars down the road.
A good battery will show above 12.4volts with engine off.
After startup recharging, good alternator will show 13.5volts(at battery) with engine at idle.
With engine at 2,500rpm(approx.) voltage should go up and then drop down to 13.5v again.
At idle with 13.5v showing as you turn on lights, fan, radio, ect.....voltage should drop and then come back up to 13.5v.

1.1volts above battery voltage is the maintenance voltage, this doesn't charge the battery or allow battery to be drained.
If your battery voltage is 12.6v then at idle you would see 13.7v, 1.1v above battery voltage.

Just after startup battery is drained, alternator will then run at 2volts above battery voltage to recharge battery, so 14.4 to 14.8volts would be normal.
This should only last for a few minutes, if it lasts longer battery will start to "cook", fluid inside evaporates, yes even on "sealed" batteries, and battery life will be cut short.

 

[Scrambler82]

Good to hear you might have it.
I would have suggested a new ground wire run from the housing to a good grounding point on the frame and then check the grounds from the frame to the battery.
Even if you get things back together running a new grounding system that bypasses the engine block is a plus for the charging system.

 

[YungICY]

I like to think out loud on here sometimes kowboy haha.



The voltmeter was how I came to the conclusion it was in correct operation after I fixed it. Did a couple of google searches and it said 13.5v is charging correctly. And when I started her back up the dash lights came back to bright and my turn signal lights didn't delay (always the first sign).



Thanks for the advice on the ground wire scrambler. What gauge wire should I use for A-alternator to frame, and B-frame to battery?


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[Scrambler82]

Thanks for the advice on the ground wire scrambler. What gauge wire should I use for A-alternator to frame, and B-frame to battery?

Since you don't want to do it again IF you happen to upgrade to a larger output alternator, I would do a 2 gauge fine stranded cable. Make sure the connections are mechanical crimped well and then solder them (optional) and use an adhersive type heat shrink over the connector joint. Make sure to get to bare metal, use a good quality external tooth lock washer between the nut and connector and s/s bolt also use some conductive anti corrosion paste on, inbetween the connection.

If you can get enough 2 gauge cable, after running the ground to the frame, make that a central point, run a cable to the negative terminal on the battery AND one to bolts on the starter mount, from the engine to the central point and from the cab to the central point.

My plan... When ever I get to it, is all of the above and one to the rear of the vehicle to cover all of the components in the rear.

We can go on and on with upgrades to the ranger wiring but these grounds mentioned in the first part will help a lot in the flow of electricity and will help all of the components attached to the new wiring and will make the bulbs burn brighter and other component last longer.

Sorry for carrying on, get it done !

 

[YungICY]

Thank you for the advice. I have been thinking about upgrading the alternator but I'm not an electrician by any means. I'm currently running the 60 or 65 amp. How big can I go? I was thinking somewhere around the 100 amp range.


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