Electrical Problems?
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You are currently reading a thread in /o/ - Auto
You are currently reading a thread in /o/ - Auto
OK guys, got an electrical issue on my F250 (inb4 hurr hurr it's a ferd). I get intermittent charging, then nothing. Lately it's been nothing and I'm driving on battery. I'm torn as to whether or not it's the alternator, or something in between. Any ideas?
>>14018479
Does the alternator have an external regulator? They're really easy to change, usually wear out before the rest of the alternator does, and pretty cheap. If your battery light is going on and off, it's a fair bet.
>>14018515
Built in regulator. What I can't figure out us why I get 14.5V for 3 minutes after start, the in back on just battery. Also belt is not slipping.
>>14018479
>Lately it's been nothing and I'm driving on battery
That makes no sense. You can't just 'drive on battery' unless you charge it up with a charger and don't go very far or don't shut off the car until you get home.
Have you checked battery voltage while the car is on?
>>14018684
Does the idle drop after three minutes? Try picking the revs up a bit. Alternators don't work real well at low speeds.
Otherwise I'm shit outta ideas.
>>14018732
No idle problems, I'm thinking it's gotta be the regulator.
>>14018699
I have been charging it up. But im not getting g a charge while running. I know it's not good but I've been able to make it to work and back on battery alone.
>>14019190
How are the battery terminals? Try cleaning them if they are dirty.
>>14018684
Most alternators have more than one wire going to it. The large one is the main charging line going to the battery, and the others are for the field excitation. The field excitation circuit senses the output voltage and regulates it, and charges a small coil so the alternator works (namely, for lower RPMs and high current applications, as the alternator usually becomes self-exciting at higher RPMs). This would be your starting point; find a good article on wiring it/diagnosing your specific model of alternator. I know most Delco and motorolla alternators work this way, but to be honest I can't remember what Ford used for any of their vehicles. See attached photo for an example of a Delco SI series of alternator.
Usually, if regulators/diodes go out, it's all or nothing, or low charging current. But they do go out often, and have weird symptoms while doing so.
You don't describe your vehicle well (what year? engine? model of alternator?), and your problem is vague at best. Your best bet would be to re-tighten the belt (if v belt or without a tensioner) or add belt dressing, then diagnose the wiring, as doing those are next to free. If that doesn't work, then likely it is your regulator circuit.
Also, >>14018699
It's very much possible to drive on battery alone. Two years ago I had electrical issues on my CJ7 and had to spend a week driving 60 miles round trip on battery alone to get to work. It was late fall and early in the morning, so I often had to choose between headlights or heater fan for the majority of the ride. The heater fan would usually kill that sucker fast, and I don't think I ever measured above 9 or so volts by the time I got home. Turns out the bearing seized up and the belt would spin around the alternator, and didn't make noise or squeal. It was dead silent, and took me forever to realize it wasn't turning the alternator.
>>14019196
They were a little dirty, and I am going to replace the negative clamp as it is pretty wore out. What's been throwing me off this whole time is how it will randomly start charging, then drop out. I dont know how to test the regulator to see if it's bad, but alternators are cheap enough I'm probably going to replace it in the morning when I get home. And thanks to all who have replied so far, any ideas are helpful. Fuck I hate electrical problems.
>>14019376
I was thinking of trying belt dressing, but the pulley is turning. I suppose it could be missing excitation voltage, perhaps some inline fuse. I haven't done much by the way of continuity testing, I will do more in the morning when I get home before pulling it.
>>14019376
>It's very much possible to drive on battery alone.
It's possible, but it's a very bad idea and it doesn't work very well. I'm sure you found out that discharging below 10 volts is very bad news for your battery, also.
>>14019439
Also it's a 1999 and I believe it's a motocraft ALT.
