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Also - can I drive the car like this or am I asking for trouble. I just need to move it out of the garage, turn it around, and put it back in. Am I risking frying something by doing this?

Thanks

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When I test the POS voltage drop (from IGN at the regulator to the + battery terminal) I was getting 1.5, so I have a problem somewhere else in the system.Where do I go from here?

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Whats the voltage do when you rev the engine? if it continues to climb you need to disable the charging system to move it, if it stays constant then move the car... Unplugging the voltage regulator should disable the charging system, if it doesn't than that would be a huge clue... When you did the voltage drop test did you test from the blue wire at the voltage regulator to the battery? That is where the regulator is sensing the voltage so it's the key point... Let us know more info is always good...

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Make sure the voltage drops when you unplug the regulator... If the alternator is internally full fielded or if the green wire from the alternator to the regulator is grounded disconnecting the regulator won't stop the ocercharging condition & that can cause lots of problems including the battery exploding....


Edit, just looked at your vehicle list, I'd previously assumed you have a two wire alternator... Most of the info stays the same but... I need to check color codes on the early harness

Oh yeah, do you like Black cars??

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I have the single field, one-wire alternator version. Do I need to disconnect both sides of the regulator connections when I un-hook it? Seems like I could just pull the IGN side (right side) and leave the FLD (green wire) connected, right?

And yes! All cars are supposed to be black. My driveway looks like a perpetual funeral.

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Hey all,

I did the Amp meter bypass thing last week and now my new voltmeter shows I'm getting 16V at idle. I spent all morning reading the voltage regulator test threads. I grounded the case to the batter, no change. When I test the POS voltage drop (from IGN at the regulator to the + battery terminal) I was getting 1.5, so I have a problem somewhere else in the system.

Where do I go from here? Start pulling fuses like I would for a short and figure out which circuit is causing the voltage drop?

Also - can I drive the car like this or am I asking for trouble. I just need to move it out of the garage, turn it around, and put it back in. Am I risking frying something by doing this?

Thanks

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Now you need to find the drop in all that wireing. Check all connections, especially and including the firewall/ bulkhead connector. Check the connector at the ignition switch, AND CHECK THE DROP across the switch, IE check the battery feed INTO the switch, and the ign feed coming OUT of the switch. SOMEWHERE in that path you are losing that 1.5V.

Guess what? Let's say the regulator "liked" 14.5?

14.5 + 1.5==16v!!!!

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Thanks for the info (and nice math, btw )

I'm just curious though - it seems like you are saying that the drop would be somewhere in the ignition switch wiring (most likely). I'm curious as to why something like, say, a bad headlight switch would not also cause this. Is it because I'm not looking at a short to ground issue, but an issue with the flow of 12v+ through the 12V+ wiring circuit.

Hmm - I think I answered my own question, now that I think about it. A bad 12V+ on my headlight switch (as an example, or the radio or my heater blower motor) would not "fool" the regulator into thinking it needed more juice. And if one of those items were shorted to ground it would be obvious.

Thanks again everyone for all your help. How did people work on old cars before the internet?

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Hey all,

I did the Amp meter bypass thing last week and now my new voltmeter shows I'm getting 16V at idle. I spent all morning reading the voltage regulator test threads. I grounded the case to the batter, no change. When I test the POS voltage drop (from IGN at the regulator to the + battery terminal) I was getting 1.5, so I have a problem somewhere else in the system.

Where do I go from here? Start pulling fuses like I would for a short and figure out which circuit is causing the voltage drop?

Also - can I drive the car like this or am I asking for trouble. I just need to move it out of the garage, turn it around, and put it back in. Am I risking frying something by doing this?

Thanks

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YOU HAVE ALREADY FOUND YOUR ANSWER. What is happening is that in all the harness, connections, bulkhead connector, etc PATH from the battery pos to the ign. switch and back out to the ign terminal on the alternator, you have 1.5V of DROP

To be sure (and it is!!) the problem, hook a good big jumper, IE jumper cable, or no12 or larger from the regulator ign directly to the battery, and see if the charging system voltage drops to normal--it should!!!

Now you need to find the drop in all that wireing. Check all connections, especially and including the firewall/ bulkhead connector. Check the connector at the ignition switch, AND CHECK THE DROP across the switch, IE check the battery feed INTO the switch, and the ign feed coming OUT of the switch. SOMEWHERE in that path you are losing that 1.5V.

Guess what? Let's say the regulator "liked" 14.5?

14.5 + 1.5==16v!!!!

Check the main feed (for drop) from the batt pos to the main feed into the switch THAT WILL ELIMINATE all the wiring from the battery to the switch. If you have considerable drop there, then it is in that section.

Check the ign run terminal OUT of the switch, check the drop between there and the ign terminal of your regulator. If you have considerable drop there, it's probably the bulkhead connector, because that's about the only thing "in the path." Dont forget the ENDS of the conductor--the crimp-on connectors themselves may be bad.


ALSO if you have ADDED a bunch of stuff to ign run such as fans or who knows what, something there is almost guaranteed to be causing the drop, so unhook, or use relays.

Speaking of relays, if you CANNOT find the problem and want an easy way out, one way of "solving" the problem would be to put a decent quality firewall mounted relay on the car, use the ign feed to "fire the relay, and then feed your regulator from the relay. Feed the relay from a good solid battery connection such as the starter relay

You can check that hookup before you do so by unhooking the regulator ign, use a jumper from the stater relay to the regulator ign, and see if the problem goes away.

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your voltage drop is doing this. If you fried the main feed the terminal is toast and will have higher resistance so look at those terminals unless you've already replaced them. Next thing is the ign switch.

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Hey all,

I did the Amp meter bypass thing last week and now my new voltmeter shows I'm getting 16V at idle. I spent all morning reading the voltage regulator test threads. I grounded the case to the batter, no change. When I test the POS voltage drop (from IGN at the regulator to the + battery terminal) I was getting 1.5, so I have a problem somewhere else in the system.

Where do I go from here? Start pulling fuses like I would for a short and figure out which circuit is causing the voltage drop?

Also - can I drive the car like this or am I asking for trouble. I just need to move it out of the garage, turn it around, and put it back in. Am I risking frying something by doing this?

Thanks

---

YOU HAVE ALREADY FOUND YOUR ANSWER. What is happening is that in all the harness, connections, bulkhead connector, etc PATH from the battery pos to the ign. switch and back out to the ign terminal on the alternator, you have 1.5V of DROP

To be sure (and it is!!) the problem, hook a good big jumper, IE jumper cable, or no12 or larger from the regulator ign directly to the battery, and see if the charging system voltage drops to normal--it should!!!

Now you need to find the drop in all that wireing. Check all connections, especially and including the firewall/ bulkhead connector. Check the connector at the ignition switch, AND CHECK THE DROP across the switch, IE check the battery feed INTO the switch, and the ign feed coming OUT of the switch. SOMEWHERE in that path you are losing that 1.5V.

Guess what? Let's say the regulator "liked" 14.5?

14.5 + 1.5==16v!!!!

Check the main feed (for drop) from the batt pos to the main feed into the switch THAT WILL ELIMINATE all the wiring from the battery to the switch. If you have considerable drop there, then it is in that section.

Check the ign run terminal OUT of the switch, check the drop between there and the ign terminal of your regulator. If you have considerable drop there, it's probably the bulkhead connector, because that's about the only thing "in the path." Dont forget the ENDS of the conductor--the crimp-on connectors themselves may be bad.


ALSO if you have ADDED a bunch of stuff to ign run such as fans or who knows what, something there is almost guaranteed to be causing the drop, so unhook, or use relays.

Speaking of relays, if you CANNOT find the problem and want an easy way out, one way of "solving" the problem would be to put a decent quality firewall mounted relay on the car, use the ign feed to "fire the relay, and then feed your regulator from the relay. Feed the relay from a good solid battery connection such as the starter relay

You can check that hookup before you do so by unhooking the regulator ign, use a jumper from the stater relay to the regulator ign, and see if the problem goes away.

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your voltage drop is doing this. If you fried the main feed the terminal is toast and will have higher resistance so look at those terminals unless you've already replaced them. Next thing is the ign switch.

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Now you need to find the drop in all that wireing. ...... SOMEWHERE in that path you are losing that 1.5V.

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I'm just curious though - it seems like you are saying that the drop would be somewhere in the ignition switch wiring (most likely). I'm curious as to why something like, say, a bad headlight switch would not also cause this. Is it because I'm not looking at a short to ground issue, but an issue with the flow of 12v+ through the 12V+ wiring circuit.

Hmm - I think I answered my own question, now that I think about it. A bad 12V+ on my headlight switch (as an example, or the radio or my heater blower motor) would not "fool" the regulator into thinking it needed more juice. And if one of those items were shorted to ground it would be obvious.

Thanks again everyone for all your help. How did people work on old cars before the internet?

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You've got it. The bad headlight switch would only make the headlights dimmer, not affect the rest of the car.

The problem here, is that your voltage regulator is not seeing an accurate system voltage.

It thinks the voltage is 1.5 lower than it really is. SO it keeps charging until it sees 14.5

The fix CAN be easy.

You could look for the drop, and you may find part of it, or all of it in one or more of the components(switch, bulkead connector, wiring..etc)
It may be easy to find, it may be difficult. You may only find part of it, etc..

I have done a different repair in the past, and it always seems to work.

Get a simple foglight relay from a parts store.

A relay has a low power (control) circuit, and the heavy switched(load) circuit that is used for whatever the relay is actually powering/supplying power.

Mount this right next to your regulator.

Remove the existing "ignition on" wire from the regulator, and wire it to the control circuit of the relay. ground the other side of the control circuit.

Then run heavy wire from the relay directly to the main alternator pos post or the battery poitive post. This goes on the heavy circuit of the relay. Wire the other side of this relay circuit to the regulator.


What you are doing here, is this...

Originally, The exisiting ignition wire turns on the regulator, AND provides it an input that the regulator uses as it's monitor for system voltage.

By wiring it as I have described, you are using the exisiting wire to turn on a direct feed to the battery, or the alternator. It is now reading the voltage of the system directly. Any and all voltage drops have been bypassed. IT still works by turning the key, and is now more accurate than it ever was.

It takes about 20 minutes to do, and 10 to 20 bucks in material depending what you already have laying around.

Good luck

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If his voltage drop is doing this & there is a 1.5v drop then why when he revs the engine does the voltage continue to climb? the regulator should limit it to the 1.5v above it normal limit IE max 16v but in reality most single wire systems limit around 14.2 plus 1.5 would be 15.7... Instead his will climb past 16v...

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It could be that the drop get's worse as the amperage output increases.

It could also bee that the drop is one issue, and that the alternator is shorted internally too.

I'd chase the drop issue first, then see what happens

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If his voltage drop is doing this & there is a 1.5v drop then why when he revs the engine does the voltage continue to climb? the regulator should limit it to the 1.5v above it normal limit IE max 16v but in reality most single wire systems limit around 14.2 plus 1.5 would be 15.7... Instead his will climb past 16v...

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If his voltage drop is doing this & there is a 1.5v drop then why when he revs the engine does the voltage continue to climb? the regulator should limit it to the 1.5v above it normal limit IE max 16v but in reality most single wire systems limit around 14.2 plus 1.5 would be 15.7... Instead his will climb past 16v...

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Good point. I'll probably also replace the regulater next week. It looks fairly new, but I can't recall if I replaced it two years ago when I bought the car. This car has not been driven since 1988, so I'm not surprised by anything that crops up. (Extremely disappointed, but not surprised)

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If his voltage drop is doing this & there is a 1.5v drop then why when he revs the engine does the voltage continue to climb? the regulator should limit it to the 1.5v above it normal limit IE max 16v but in reality most single wire systems limit around 14.2 plus 1.5 would be 15.7... Instead his will climb past 16v...

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It could be that the drop get's worse as the amperage output increases.

It could also bee that the drop is one issue, and that the alternator is shorted internally too.

I'd chase the drop issue first, then see what happens

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Then run heavy wire from the relay directly to the main alternator pos post or the battery poitive post. This goes on the heavy circuit of the relay. Wire the other side of this relay circuit to the regulator.

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