High volts

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Had the same problem. I had a bad ground between the regulator and firewall.
tmm
 
Ok look, you have to get this down to "the basics" and go from there.

1--There is SOME possibility that the battery itself could cause this, so try a known good battery out of another vehicle temporarily.

2--The regulator itself could be a problem, but you have replaced that.

3A--This leaves the sense voltage

3B--and the ground between the regulator and battery.

YOU MUST CHECK THESE in the following manner!!!



A---To check the sense voltage, Turn the key to run, but with engine OFF. Stab one probe of your meter into the battery POS post, and clip your other probe to as close to the regulator IGN terminal as you can get. Since you are having so much trouble, I'd be tempted to stick a pin through the blue regulator wire in an attempt to eliminate as much as possible.

Again, you want to see LESS than .2V, the less the better.

More voltage means you have a voltage drop problem in the harness. Your top suspects are the regulator connector, the bulkhead connector, the ammeter circuit, the ignition switch connector, and the switch itself. Also check the connections at the coil resistor. That is, the crimps in the connectors

B---To check the ground, get the engine running, the battery charged, and do the following check twice, first with everything in the car shut off (except the engine) and again with heater, lights, etc turned on.

Stab one probe of your meter onto the NEG. battery terminal, and stick the other probe directly onto the mounting flange of the regulator. You should read less than .2V (two tenths of a volt). More voltage means the regulator is not actually grounded to the battery NEG.
 
txstang84 said:
dunno how much more this thing can be grounded
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I need to brush up on my Ohms Law but shouldn't the resistance be closer to zero? 2 pieces of metal with a sheet metal screw connecting the 2 should have no resistance. All ground connections should be against bare metal and star washers used. tmm
 
toolmanmike said:
I need to brush up on my Ohms Law..
Click to expand...

ha ha...very funny. In any case, I remeasured again this morning... 0.9 ohms...I'll call it poor test.

Ok look, you have to get this down to "the basics" and go from there.

1--There is SOME possibility that the battery itself could cause this, so try a known good battery out of another vehicle temporarily.

2--The regulator itself could be a problem, but you have replaced that.

3A--This leaves the sense voltage

3B--and the ground between the regulator and battery.

YOU MUST CHECK THESE in the following manner!!!



A---To check the sense voltage, Turn the key to run, but with engine OFF. Stab one probe of your meter into the battery POS post, and clip your other probe to as close to the regulator IGN terminal as you can get. Since you are having so much trouble, I'd be tempted to stick a pin through the blue regulator wire in an attempt to eliminate as much as possible.

Again, you want to see LESS than .2V, the less the better.

More voltage means you have a voltage drop problem in the harness. Your top suspects are the regulator connector, the bulkhead connector, the ammeter circuit, the ignition switch connector, and the switch itself. Also check the connections at the coil resistor. That is, the crimps in the connectors

B---To check the ground, get the engine running, the battery charged, and do the following check twice, first with everything in the car shut off (except the engine) and again with heater, lights, etc turned on.

Stab one probe of your meter onto the NEG. battery terminal, and stick the other probe directly onto the mounting flange of the regulator. You should read less than .2V (two tenths of a volt). More voltage means the regulator is not actually grounded to the battery NEG.
Click to expand...

1. Tried two different batteries in known good condition...after idle and volts stabilized, no difference... >15V at battery

2. Yup...I'm not replacing it 4 times...these things aren't free and I'm thinking after three, there's something else broke or at least not right.

3A. With key on, engine off voltage loss measured at <TADA!!> 1.1V when probed between (+) battery terminal and IGN voltage measured 1" from VR connector

Key on, engine running voltage was 0.9V...

bulkhead connectors were cleaned yesterday (or the day before, can't recall) and although checking continuity through them is a little difficult, there was no difference before/after with voltage at battery.

Ammeter circuit is bypassed, but voltage from the alternator still passes through the cabin at the original bulkhead connector, and still feeds the fuse block with full voltage (currently >15V). I also installed fuse links inline with that wire so it wouldn't draw too much current through the bulkhead...

The ballast resistor show ~14.5V at the ignition side and ~8.7V on the coil side, and I cleaned the terminals on both sides...I don't know how much resistance is supposed to be there...but it's a carry over from when it had points.

Ignition switch...might be something there...here lately-can't recall exactly when it started, but sometimes when I go to start the car, the relay only clicks and nothing happens. And since you're the 2nd or 3rd person to suggest it may be at fault along with the occasional problem I just mentioned, I might have a bad switch.

3B. See above... 0.9 ohms as measured directly from VR housing to nearby chassis ground (bolt holding ballast resistor)

With engine running and nothing else energized, voltage measured as directed (one probe on batter (-), one on VR housing/mounting flange) was 9 mV or 0.009V

With all high drain stuff on, and stable idle, voltage measured as directed was 27 mV or 0.027V

...I think it's safe to say, the VR is satisfactorily grounded.

So, I might be going after an ignition switch.
 
years ago I had a ign coil short to ground. It caused the alt to charge like a sumbich. Just something to check if you have a spare coil. Btw the car ran fine.
 
harleydartguy said:
years ago I had a ign coil short to ground. It caused the alt to charge like a sumbich. Just something to check if you have a spare coil. Btw the car ran fine.
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Couldn't possibly run if the coil was grounded. You'd get no spark.

To the OP, the biggest culpret in these older cars is resistance cause by poor electrical connections &/or bad grounds. The bulkhead connectors are a usual suspect, but cleaning isn't enough. Make sure the pins fit snugly into each other & the wires are attached to the pins firmly. And clean doesn't mean spray & wipe clean. It means shiny metal clean! Go through every connector in the circuit & make sure they're good.
 
Sounds like your grounds are good and drops thru the ignition switch and connectors is the culprit. The Vreg is doing its job fine. It commands whatever alternator you have installed "more or less" until it senses the ~14.5 V setpoint it wants. Your problem is that the sense comes after the IGN switch and you have higher voltages elsewhere, thus a drop thru the IGN switch and/or other series components exists.

It would be better to bypass the ammeter in the engine bay, so it doesn't have to loop into the cabin and back thru the bulkhead terminals (and melt it). You can do that by running a ~8 awg cable from alternator big stud to the starter relay big stud (BATT+) or straight to BATT+. However, those w/ a 63 or 65 car have separate "buss lugs" for those w/ solid screw connectors, so melting bulkheads is not a problem.
 
Well, I did bypass it by doing exactly what you mentioned-I ran an 8ga wire directly to the battery side of the starter relay...however, I retained the other 10ga wire that ran thround the bulkhead with a fuse link so I could keep the circuits fed by it inside the cab since it feeds the fuse box.

After all this nonsense, I'll probably run that wire over from the starter relay as opposed to the alternator charge post...
 
I fought with a similar issue last summer where the alternator was putting out 15+ volts and found the problem to be in the harness connector on the steering column that has the ignition switch on it. The connections were severely corroded and the harness connector was partially melted. I wound up removing the stock connector altogether...problem solved, it dropped down to 14.0 volts.
 
txstang84 said:
Well, I did bypass it by doing exactly what you mentioned-I ran an 8ga wire directly to the battery side of the starter relay...however, I retained the other 10ga wire that ran thround the bulkhead with a fuse link so I could keep the circuits fed by it inside the cab since it feeds the fuse box.

After all this nonsense, I'll probably run that wire over from the starter relay as opposed to the alternator charge post...
Click to expand...

Running a jumper from the battery to the starter relay does NOTHING. Please re--read my post

Here is the path that you are up against:

"Hot side:"

The voltage that the regulator IGN terminal "sees" MUST be within a very few tenths of a volt as the battery. How does battery voltage "get" to the regulator IGN terminal?

This path:

Battery---starter relay--fuse link--bulkhead connector--ammeter--in harness splice--ignition switch connector--through the switch--out the switch connector (dark blue ignition wire)--back out the bukhead--to the

ballast resistor

regulator "I" terminal

alternator field on 70/ later vehicles

some smog equipment on some vehicles, IE choke heater, distributor solenoid, idle solenoid

ANY of the items in the above "path" can cause voltage drop---any connector, and in fact occasionally, one of us finds a broken in-harness splice. This is a large splice in the black ammeter wire which splits off and feeds the headlight switch, ignition switch, and the fuse panel "hot" buss.



f
 
txstang84 said:
...............3A. With key on, engine off voltage loss measured at <TADA!!> 1.1V when probed between (+) battery terminal and IGN voltage measured 1" from VR connector.................
So, I might be going after an ignition switch.
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THIS RIGHT HERE tells the story.

Your trouble is somewhere in the circuit path I mentioned

Get yourself a diagram and go through this path. Measure the "easy to get to" points first, then get to whatever you can in between

The ignition switch/ switch connector is one place you can access

The interior side of the bulkhead connector

You say the "ammeter was bypassed" but not knowing how you did this, IE if you simply bolted the ammeter wires together, the problem could STILL be the wire ends themselves, or the "in harness" splice

"Running voltage" and ohmeter checks are meaningless.

What you want is the circuit under load, engine not running, key in "run." This causes the regulator/ alternator field to draw current and put a load on the circuit path. As you check the path from battery, through the firewall, switch, back out, the drop "criminal" will show up.
 
Running a jumper from the battery to the starter relay does NOTHING. Please re--read my post
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please re-read that post as it is a reply to Bill...not a statement saying I ran a jumper from the battery to the starter relay. I'll confess to not being the brightest bulb in the box when it comes to troubleshooting electrical components, but I'm also not that lost...thanks
 
txstang84 said:
please re-read that post as it is a reply to Bill...not a statement saying I ran a jumper from the battery to the starter relay. I'll confess to not being the brightest bulb in the box when it comes to troubleshooting electrical components, but I'm also not that lost...thanks
Click to expand...
You did the ammeter bypass correctly. You are right that you need to leave both cables going into the cabin, since that is the only way to power the cabin. Actually, you probably need just the ALT cable since all loads come off that. The BATT cable is in series with the ammeter, to measure all flow into or out of the battery to the cabin, the only exception being special accessories like spot-lights. For hard-core electronics types, I pioneered a way to keep your ammeter working yet start bypassing it at higher currents (search).

Your problem (as many say) is that the voltage after the ignition switch, in the engine bay, is 1.1 V less than at the battery. A common problem (see 73Scamp318's post) and easy to find and fix. Maybe not in a 1972, if you have the key switch in the steering column, but there is a great post with photos for getting to it.
 
I've read and reread this thread, to bad i'll never understand it :( Son just blew out 2 new headlights when ammeter pinned it self. It came down after a bit at idle so he idled it home. We replaced v reg, had auto parts store run system check alt ok, batt ok, starter slightly low amp draw @ 11.97 starts fine, still charging at 15.4 well it is what it is for now. I'm gonna keep reading here though.
 
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th_VoltageDrop_zps92b55833.jpg
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Cool video...I performed that test yesterday and found 1.1V drop.

I slaved in a new ignition switch this morning and found no difference in the operation or votage, so I have a connection or wire somewhere in there that's probably toasty. I'll get after it again (hopefully) this weekend in between doing favors for folks...
 
txstang84 said:
Cool video...I performed that test yesterday and found 1.1V drop.

I slaved in a new ignition switch this morning and found no difference in the operation or votage, so I have a connection or wire somewhere in there that's probably toasty. I'll get after it again (hopefully) this weekend in between doing favors for folks...
Click to expand...

Thanks. Have seen Del (67Dart273) explain it to so many people, including me, that I thought a 2 min vid might help some of the more visual types down the road.

I started out with 1.5 loss and after a new ignition switch and a couple of new connections have gotten down to .7. Will begin the chase again this weekend.
 
plum crazy dart said:
I've read and reread this thread, to bad i'll never understand it :( Son just blew out 2 new headlights when ammeter pinned it self.
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Tell us what you don't understand.
Do you have a digital multimeter (DMM)? If not, I'll never understand why people try electrical trouble-shooting without one.
Do you have a wiring diagram? Ditto above.
The voltage difference from the case of Vreg (blk DMM lead) to the IGN wire (red DMM lead) should be close to the voltage difference across your battery (from BATT- to BATT+). It should normally measure ~14.5 V. If much higher, you have an excessive drop thru your wiring, ignition switch, grounds, and/or connectors. Use your DMM to find the drop(s).
Don't know how to use a DMM? Check youtube.

The video posted above is great (apparently a Berkeley grad, like my older son!). I'll add a few comments:
a) The Vreg's shown are for the early "round-back" alternators (1 field terminal). If you don't have an electronic one (1st shown), get one, though some electronic ones are packaged in the 2nd big case.
b) In addition to checking for minimal drop from BATT+ to Vreg sense, also check the drop from BATT- to the case of Vreg.
c) I never rely on getting a ground thru the sheet metal screws and always run a separate wire to the case.
 
Well, I found parts of my overall voltage drop culprit:

overall loss from batt (+) to VR = ~1.1V key on, engine off
loss from batt (+) to firewall side of bulkhead connector ign wire = ~ 0.45V
loss from ign wire bulkhead connector to ballast resistor = > 0.5V (this concerned me-nearly half a volt just in a couple feet worth of wiring!)

I also measured loss from the inside of the cabin from the connector to the ignition switch harness

loss with old switch 0.35V~0.4V
loss with slaved in new switch 0.29V~0.31V
loss with slaved in new switch #2 0.25V~0.29V

I checked condition and loss along the battery feeds all inside the car; if there was any loss measured, it was something like 0.2mV or less. So, the physical wiring inside the car isn't bad, but the bulkhead connectors are a little loose, and the ignition switch still won't pass the 0.2V loss hurdle even if all else was well.

Granted, I didn't have the switch installed in the column at the time, and that may have something to do with it (grounding??). In any case, looks like I'll be shopping for an ignition harness before I can make any headway with it.
 
txstang84 said:
overall loss from batt (+) to VR = ~1.1V key on, engine off............................
loss from batt (+) to firewall side of bulkhead connector ign wire = ~ 0.45V.
Click to expand...


Don't understand. The firewall has TWO sides, the engine side and the interior. Which side? If you are talking about the ENGINE side, then the bulkhead connector itself is probably to blame

QUOTE=txstang84;1969879600]loss from ign wire bulkhead connector to ballast resistor = > 0.5V (this concerned me-nearly half a volt just in a couple feet worth of wiring!).[/QUOTE]

I assume? guessing? you are measuring from the engine side of the firewall to the ballast? Assuming your meter is making good connections, it is the CRIMP connections themselves, and that right there is half your problem, no pun, 1/2 a volt!!!!!!


QUOTE=txstang84;1969879600]I also measured loss from the inside of the cabin from the connector to the ignition switch harness[/QUOTE]

I do not understand from your description what you are measuring here. I'm guessing? the interior side of the bulkhead connector to the connector at the ignition switch?

Which wire? ignition run? which SIDE of the ignition switch connector? under-dash harness side? ignition switch side?

If the last is true, that seems OK.

One way to do this is "rig" a long clip lead to the battery hot terminal, and LEAVE it there. "Big stud" on the starter relay is OK.

Now work along the "chain" and be specific, some of these parts of the "chain" are easier to get to than others

The following might be example readings, key on, engine off

Starter relay stud---zero volts

Fuse link at engine side bulkhead connector (unless modified): zero

Fuse link wire at interior side of bulkhead (unless modified): .05 ?? volts

ammeter terminals (unless modified): .07 V

Ignition switch connector, battery feed, switch side: .085v

Ignition run wire out of ignition switch, switch connector, dash harness side: .098v

Ignition run wire on engine side of bulkhead connector, .1v

Ballast resistor at ignition run wire, .15v

Notice each connector adds a small amount to the mix.


If I understood your last posting, you lost nearly a half volt from the engine side of the bulkhead, in the ignition run wire, to the ballast resistor. The "only thing there" is a crimp connector on each end of the wire!!!!.
 
txstang84 said:
In any case, looks like I'll be shopping for an ignition harness before I can make any headway with it.
Click to expand...
The measurements really help. I doubt you need another harness, unless the insulation on your wires is old and brittle. The copper should be fine. You just need to clean the connectors, and maybe solder the crimps. You can remove the terminals from the bulkhead connector fairly easily by squeezing the long way w/ needle-nose pliers. Look at photos of "56 terminals" on ebay to understand. Label the connector w/ a Sharpie A-H and record the color wires before removing, or do 1 at a time. Spray Contact Cleaner in female terminals or ones you can't remove.
 
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