1966 Barracuda not Charging

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Steve Clason

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Piercetom, IN
My 66 cuda won't charge. What I've done thus far:
new voltage regulator (2)
new alternator
assurred grounds are clean and working with ohmmeter
checked fusable link it is good
battery and output voltage at alternator are the same
with field wire grounded to battery with jumper the best voltage from the alternator is 11.89
tried other varied tests from prior threads that were similar
What else can I check?

My thought is a bad alternator so I took it to O'Riley's and the only test that failed was the voltage regulator test which of course this alternator doesn't have built in.
The alternator is a 400-1006 60A neg ground from DV Electronics. The typical 2 pulley with the battery output and 2 field terminals.

The voltage regulator is a Master pro 2vr9.

Any suggestions are welcome. I've almost got this sweet reide ready for action.
 
Have you checked your voltmeter against a known voltage to verify accuracy? Do you have a working ammeter in car? Does revving engine change voltage? Belt is tight enough so Alt is not slipping.
 
Have you checked your voltmeter against a known voltage to verify accuracy? Do you have a working ammeter in car? Does revving engine change voltage? Belt is tight enough so Alt is not slipping.
Yes have 2 voltmeters both same
Ammeter shows slight discharge
Revving has 0.02 impact on volt
Belt is tight

Thanks for the ideas!
 
If the alternator has two fields one of them goes to the vr and the other needs to be grounded
 
First of all stop throwing new parts at the problem.
New is not always better.

Second.
Learn to read the ammeter.
The ammeter shows how much current is flowing in or out of the battery.
This is conditional. Change the conditions and it will change.
The system voltage is also somewhat conditional. A battery that measures 12.8 Volts with no load on it may measure as low as 9 Volts when starting.
Just as important is the location of the voltage reading. Current along a path remains the same. But when current flows through resistance it loses voltage. Since you measured votlage at boththe battery and the alternator output I think you understand all that.

A battery with 11.9 Volts with no load is well below fully charged. Charge it on a charger if that's what you are reading.

As you have figured out, a slight discharge while the engine is running indicates the battery is supplying system power, therefore the alternator system is not working.
In that roundabout way the ammeter is an 'alternator gage'. But remember it does not show alternator output, just whether current is flowing in or out of the battery.

The power and charging system should looked like this.
upload_2020-8-6_9-6-23.png
 
The diagram above shows a positive controling voltage regulator.
The voltage at the ignition terminal of the regulator determines how much current the regulator will let pass through to the alternator.
If the voltage is well below the setpoint, say 11.9 Volts, then the regulator will let as much current through as the alternator's rotor wants.

You describe using an alternator with two insulated field terminals. It can be used with a positive controlling regulator by grounding one of those terminals.
OR it can be used with a ground controlling regulator. To do so a second wire needs to be added to the system. It runs from one of the field terminals to the triangular plug on the regulator.

Knowing which setup your car has will make it easier for us to suggest the test method.
 
Field
The connections are labled field because when electricity flows through the rotor windings it creates an electromagnetic field.

The terminals connect to cabon brush that contact the slip ring.
upload_2019-4-13_15-33-27-png-png-png-png.png

When the voltage is at or near 14 Volts, the regulator reduces or cuts off the flow of current to the rotor.

Two insulated field terminals
With a positive controlling regulator, like the one you bought, the second terminal needs to be grounded.
Something like this will do.
upload_2020-6-15_21-54-32-png.png


That makes it the same as alternator with only one brush in an insulated holder.
upload_2020-6-16_22-50-35-png.png


That's why the phrase 'two field' or 'dual field' is really misleading. In both types there's only one rotor and only one magnetic field created when power flows through them. The difference is the number of terminals that need to be wired.
 
Field
The connections are labled field because when electricity flows through the rotor windings it creates an electromagnetic field.

The terminals connect to cabon brush that contact the slip ring.
View attachment 1715573616
When the voltage is at or near 14 Volts, the regulator reduces or cuts off the flow of current to the rotor.

Two insulated field terminals
With a positive controlling regulator, like the one you bought, the second terminal needs to be grounded.
Something like this will do.
View attachment 1715573617

That makes it the same as alternator with only one brush in an insulated holder.
View attachment 1715573618

That's why the phrase 'two field' or 'dual field' is really misleading. In both types there's only one rotor and only one magnetic field created when power flows through them. The difference is the number of terminals that need to be wired.

That's great information. I tried the ground wire addition from the second filed still not getting above 11.9 from the alternator.

I've not tried all the above things in the thread yet but will soon!
 
Lets get back to "simple" first OK?

Here's what you can/ have

Jumpering power to the field is an excellent step as it eliminates the field wiring to the regulator, and the regulator itself

So what might be?

YOU DO NOT GROUND THE FIELD to test!!! Insteand, Run a jumper from BATTERY PLUS to the alternator field terminal. (Did I misunderstand what you did?)

Make CERTAIN the field is drawing current. Many rebuilds come as an isolated field, IE both brushes insulated, so in that case you must GROUND the field terminal not connected to the regulator (green)

Make certain the alternator output stud is not cut loose from the battery

So:

With engine off, disconnect alternator field wire. Check field continuity to ground. If it is open stop and find out why. If it shows continuity (and if you have an ammeter function on your multimeter) wire your meter IN SERIES with the alternator field to the battery + and measure current draw. Should be at least 2-3A, turn the pulley and see if it changes

If this is OK, jumper the field to battery and run engine at fast idle. Measure battery voltage AND THEN measure voltage at the alternator output stud

If the output stud is "way high" much higher than battery, then charge path to battery is broken

If the output stud is low, about same as battery, it is not charging. Since you have (I hope) verified that the field is drawing current, THEN THE rebuilt alternator IS BAD
 
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Lets get back to "simple" first OK?

Here's what you can/ have

Jumpering power to the field is an excellent step as it eliminates the field wiring to the regulator, and the regulator itself

So what might be?

YOU DO NOT GROUND THE FIELD to test!!! Insteand, Run a jumper from BATTERY PLUS to the alternator field terminal. (Did I misunderstand what you did?)

Make CERTAIN the field is drawing current. Many rebuilds come as an isolated field, IE both brushes insulated, so in that case you must GROUND the field terminal not connected to the regulator (green)

Make certain the alternator output stud is not cut loose from the battery

So:

With engine off, disconnect alternator field wire. Check field continuity to ground. If it is open stop and find out why. If it shows continuity (and if you have an ammeter function on your multimeter) wire your meter IN SERIES with the alternator field to the battery + and measure current draw. Should be at least 2-3A, turn the pulley and see if it changes

If this is OK, jumper the field to battery and run engine at fast idle. Measure battery voltage AND THEN measure voltage at the alternator output stud

If the output stud is "way high" much higher than battery, then charge path to battery is broken

If the output stud is low, about same as battery, it is not charging. Since you have (I hope) verified that the field is drawing current, THEN THE rebuilt alternator IS BAD

I will try those things tomorrow. Thanks
 
I agree. But first make sure the alt and VR are wired correctly into the system!
 
Will do! I'm double checking all the wiring with the wiring diagram. The charging system is pretty simple. I did charge the battery and it is at 12.6v. The alternator is charging slightly will raise the voltage to 12.9v without a load. Drops to 11.9v with lights on. Won't get up to 12 even with increased RPM. So I'll do the various tests again tomorrow and see what I can find.

I read the ammeter in the dash can be a problem. It does move and reads discharge slightly until RPM increases. Once RPM increases it barely shows charge and when lights on goes to discharge.

The wiring harness and block are new. Should I try bypassing the ammeter and see if that makes a difference and if so are there things to avoid so I don't burn something else up?
 
Get an electronic VR and wire both terminals to it as designed, and make SURE you got a good ground to the case of any voltage regulator you use: its the ground of the system. Cheap enough and a better system, more stable and I its a faster switching system (transistor instead of points) allows a better control of the 14.2 output voltage or whatever they are set at as well as the dependability of no mechanical points to service. Some EVR's have a little screw on them to turn up the output voltage. You already have a 'dual field' alternator, if you were close I'd give you a squareback for comparison testing.
latealt.jpg
 
Get an electronic VR and wire both terminals to it as designed, and make SURE you got a good ground to the case of any voltage regulator you use: its the ground of the system. Cheap enough and a better system, more stable and I its a faster switching system (transistor instead of points) allows a better control of the 14.2 output voltage or whatever they are set at as well as the dependability of no mechanical points to service. Some EVR's have a little screw on them to turn up the output voltage. You already have a 'dual field' alternator, if you were close I'd give you a squareback for comparison testing.
View attachment 1715574549
Why? No.
For the average guy running another wire and splicing in a pigtail connector is more work and more places to have problems.
At one time, for a car going to transistorized ignition, the later VR was a good move.
But now, even with a solid state mopar ignition, a transistorized version of the positive controlling VR can be easily had.

What he needs to do now is solve the problem.
 
I'm double checking all the wiring with the wiring diagram. The charging system is pretty simple. I did charge the battery and it is at 12.6v. The alternator is charging slightly will raise the voltage to 12.9v without a load. Drops to 11.9v with lights on. Won't get up to 12 even with increased RPM. So I'll do the various tests again tomorrow and see what I can find.
Sure sounds like the alternator isn't producing what it should. Possibilities include
Belt not tight,
Open winding (there are three in the rotor and 3 in the stator)
Bad diode.

I read the ammeter in the dash can be a problem.
Don't believe everything you read.
Some of the problems people blame on the ammeter are caused by high current uses (like running a winch), or actually wiring issues ( like wires rubbing through insulation).
Some years do seem to have occasional problems. 66 does not seem to be one of them.
If you want to do a quick test of the ammeter:
Key off;
Turn on the parking lights. Should see about 4 amps discharge.
Turn on the headlights, Should see about 8-11 amps. (This amount will depend on the lamps installed and whether a 66 Barracuda has the front parking lights on when the headlights are on.)
It does move and reads discharge slightly until RPM increases. Once RPM increases it barely shows charge and when lights on goes to discharge.
Sure seems like alternator.
For a home brewed battery load test, clip the voltmeter to the battery and hit the starter.
General rule of thumb (from the SUN VAT 40 instructions) is a good battery should stay above 9.6 Volt.
67Dart273 outlined tests you can do for the alternator. Just follow that.

Should I try bypassing the ammeter and see if that makes a difference and if so are there things to avoid so I don't burn something else up?
No. The ammeter tell you how much current is flowing through it. IF you see 40 amps (max scale) flowing through it, then stop what your doing because that much current will damage wiring and connectors.
Its the high currents that damage things.

The wiring harness and block are new.
Which harness and what do you mean by 'block'?
 
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Sure sounds like the alternator isn't producing what it should. Possibilities include
Belt not tight,
Open winding (there are three in the rotor and 3 in the stator)
Bad diode.


Don't believe everything you read.
Some of the problems people blame on the ammeter are caused by high current uses (like running a winch), or actually wiring issues ( like wires rubbing through insulation).
Some years do seem to have occasional problems. 66 does not seem to be one of them.
If you want to do a quick test of the ammeter:
Key off;
Turn on the parking lights. Should see about 4 amps discharge.
Turn on the headlights, Should see about 8-11 amps. (This amount will depend on the lamps installed and whether a 66 Barracuda has the front parking lights on when the headlights are on.)

Sure seems like alternator.
For a home brewed battery load test, clip the voltmeter to the battery and hit the starter.
General rule of thumb (from the SUN VAT 40 instructions) is a good battery should stay above 9.6 Volt.
67Dart273 outlined tests you can do for the alternator. Just follow that.


No. The ammeter tell you how much current is flowing through it. IF you see 40 amps (max scale) flowing through it, then stop what your doing because that much current will damage wiring and connectors.
Its the high currents that damage things.


Which harness and what do you mean by 'block'?

Electrical connection through the firewall is what I said is block.

Have charge now!

After rerunning Darts tests and researching online what we should have for alternator and voltage regulator figured out that my vr (box labeled correct) was not the correct VR.

Thanks for all your help. I would still be spinning my wheels and not working without the assistance.
 
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