Do we have any electrical system guru’s on here? - Page 2

Chicagowil · #21 (**permalink**) 12-25-2021, 06:04 PM

The circuit must be completed to get the Alt Reg "excited". It is possible to have an Alternator that has a failing diode that will give a "false" voltage as if it is charging but it is supplying a "ripple" DC voltage charge instead of a full rectified charge. That can also damage your other electrical devices (such as a fuel pump). They are not designed to run on voltage with an "AC" component.

The original generators required a mechanic to "flash" the field to get the right polarity for the generator to charge correctly. Many a generator was installed and replaced because "shade tree mechanics" did not understand this concept.

The alternators with an internal voltage regulator need to sense the charging needs to establish its charge effect. Thus the connection after star- not the "ACC" feed.

Thom

767Jockey · #22 (**permalink**) 12-25-2021, 09:11 PM

Now I'm all confused - not hard to do when it comes to electrical.

1- If I take out the light from the circuit and install JUST a 560 ohm resistor in the line that runs from the alternator to the ignition switch, will it work?

2- Does it matter if that line runs to the IGN or ACC terminal on the iginition switch?? If so which terminal should I run it to?

PDUB · #23 (**permalink**) 12-25-2021, 09:48 PM

Quote:

Originally Posted by patrickt

It all depends on what you're wearing at the time.

[quote=incoming;1501448]Or how short the passengers skirt is[/quote]

... so he's talkin' about the red-light district. Makes more sense, now.

(Not sure why the second quote in not showing properly... it looks correct, syntactically.)

spdbrake · #24 (**permalink**) 12-25-2021, 09:57 PM

Quote:

Originally Posted by 767Jockey

Now I'm all confused - not hard to do when it comes to electrical.

1- If I take out the light from the circuit and install JUST a 560 ohm resistor in the line that runs from the alternator to the ignition switch, will it work?

2- Does it matter if that line runs to the IGN or ACC terminal on the iginition switch?? If so which terminal should I run it to?

1- yes
2- to the ign terminal

767Jockey · #25 (**permalink**) 12-26-2021, 01:33 PM

ARRRRGHHHHHH - This thing is driving me NUTS!!

I installed a 560 ohm resistor in the line that goes from the alternator to the IGN terminal on the ignition switch. I start the car and it does the exact same darned thing. It gives me 13+ volts, and within a couple of minutes it drops off line down to no charge at all. Both the voltmeter in the car and checking at the battery with a VOM confirm this, it's about 11.9 - 12.3 volts after a while.

-I have checked all the wiring. It is correct.

-I have checked all the wiring connections. They're all soldered, heat shrink wrapped and solid.

-I have checked all the grounds - battery to frame, engine to frame. They're all clean metal to clean metal and tight.

-I have checked the alternator on three different auto parts store alternator testing machines. All test good.

What the heck am I missing here? Could it be the alternator is faulty? Maybe it works initially then drops off line as it heats up or something? Other than throwing another $140 alternator on it how could I test that? Any ideas out there what ths could be? I'm pulling my hair out in frustration now.

spdbrake · #26 (**permalink**) 12-26-2021, 02:12 PM

What's your idle speed? Does it give better voltage at say 2000rpm?

767Jockey · #27 (**permalink**) 12-26-2021, 02:16 PM

No, it seems to drop off line and that's it. Every once on a while I'll look at the voltmeter while driving around the corner with it and it's up to 13v, then it's gone again. I have to believe it's the alternator. What else could it be? Either that or someting isn't right with the wire that is supposed to "excite" the alternator. If that were the case, why would it initially work and then not? I'm going to move that wire to the ACC terminal on the ignition switch and see if that does anythng, but I doubt it. If it was a bad ignition switch, the ignition would drop out as well if the switch terminal I'm on was bad too. It's not doing that. This whole thing is driving me batty.

sunman · #28 (**permalink**) 12-26-2021, 02:42 PM

Maybe the regulator has an intermittent thermal related problem.
$25 for the part, freeze it spray is about that anyway
Fix or repair daily 😬

spdbrake · #29 (**permalink**) 12-26-2021, 02:44 PM

Quite possibly could be the internal regulator cutting out once hot. Not sure if the folks who test it were under no-load conditions?
https://axleaddict.com/auto-repair/A...Regulator-Test
The regulator is only 4 screws though.
https://www.amazon.com/Voltage-Regul...ps%2C88&sr=8-6
https://www.youtube.com/watch?v=XK4SQi88WBc

patrickt · #30 (**permalink**) 12-26-2021, 03:08 PM

Quote:

Originally Posted by 767Jockey

I'm going to move that wire to the ACC terminal on the ignition switch and see if that does anything, but I doubt it.

Before you start replacing stuff, start the car up, put the VOM on it, watch how it has a nice 13+ volts and then when it drops off try wiggling the wires that go to the VR and whack the VR with the back of a screwdriver. See if you can get the voltage to bounce up by doing any of that.

sunman · #31 (**permalink**) 12-26-2021, 03:39 PM

You crack me up, I just assumed its been gently wacked with a hammer.

patrickt · #32 (**permalink**) 12-26-2021, 03:50 PM

Quote:

Originally Posted by sunman

You crack me up, I just assumed its been gently wacked with a hammer.

It is known in the trade as the "jiggle and whack" test.

767Jockey · #33 (**permalink**) 12-26-2021, 05:39 PM

I just hooked the light back into the circuit, and have the resistor bridgng the two terminals of the light. No charge, light stays on. I ordered a new regulator from Amazon for $30. If that doesn't work I'm out of ideas.

patrickt · #34 (**permalink**) 12-26-2021, 06:04 PM

Quote:

Originally Posted by 767Jockey

I just hooked the light back into the circuit, and have the resistor bridgng the two terminals of the light. No charge, light stays on. I ordered a new regulator from Amazon for $30. If that doesn't work I'm out of ideas.

In your very first post, is that graphic actually your alternator or is that just something you found and posted?

767Jockey · #35 (**permalink**) 12-26-2021, 06:06 PM

That graphic is one that shows how to hook up a Ford 3G alternator in a car that didn't have one. It depicts the exact same alternator I have. It's exactly the way I have it hooked up now.

patrickt · #36 (**permalink**) 12-26-2021, 06:16 PM

Quote:

Originally Posted by 767Jockey

That graphic is one that shows how to hook up a Ford 3G alternator in a car that didn't have one. It depicts the exact same alternator I have. It's exactly the way I have it hooked up now.

OK, and it has the voltage regulator on the back of the alternator itself. Now, is there by any chance some other external voltage regulator in this mix, maybe bolted to the footbox or something, or is the only voltage regulator the one on the back of the alternator?