Charging issue 68 barracuda

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mikewadkins

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68 Barracuda charging issues. I have replaced alternator and voltage regulator and still having charging issues. Ive disconnected wire from alternator and jumped to + lead on alternator. Get 13-15 volts at battery depending on good connection. Charges good. Ive tried connecting extra ground to VR and body. Only 12.2 volts at battery. If i jump green wire on VR to battery i also get 15v. What am i missing? My lights would pulsate so i replaced VR and was working with 14-16 on gage. It started to drop lower then 12 so i got alternator. New parts same issue.

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OK separate the problem

1....You have the components, the VR and the alternator

2....You have the output circuit, the "charging path" the big black goes from alternator output, through the bulkhead, through the ammeter, back out the bulkhead, and ends up at the battery

3.....You have the field circuit.........from the ignition switch "ignition run" comes out the bulkhead, branches off somewhere near to feed the VR, the ignition and depending on year, one or two other things.

So...............a few easy tests, part of which you did

A.....Remove green field wire, AT THE VR, and jumper it to a battery source, IE the "big stud" on the starter relay. Depending on engine RPM it should charge "full output." Go easy on RPM Doing this also confirms the green wire/ connections is OK

B.......With the above set up, run the engine to simulate low/ med. cruise. Monitor battery with a voltmeter, try to keep it below 16V. Measure battery voltage, then measure alternator output stud. Should not be more than say 1V difference, the less difference, the better

C.......If A, B are OK, the alternator, charging wire, and green wire are OK
Now with VR disconnected as before, jumper the blue and green together, it should charge just like "A" Does not hurt to check that blue supply.........so.........with key "in run" engine stopped, measure from blue VR "IGN" wire to battery PLUS. This should result in a VERY low reading, less than .3V. If more, you have voltage drop in the harness / connections

D.......If the above is OK, make CERTAIN the VR is grounded. Clean, scrape the flange and firewall and remount TIGHT with star lock washers. The VR MUST be grounded.

E......IF the above does not give results, you MAY have a bad field drawing too much current, and blowing up the VR. Set your meter up for amperage, BE CAREFUL.......Easy to eff up a meter. Post the model and photo of your meter, we can step you through that...........

Get a service manual from MyMopar and read the section 8 on alternators. There is a procedure to measure FIELD CURRENT. You want to put the field in series with our multimeter (current) to the battery. If it draws more than 6A there is something wrong
 
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Non factory wiring for sure! Was the MADD modification done to it?
 
Ive had car for about year and not sure what was done. It was working fine for the last year or so. Everything looks stock for most part. It has electronic mallery distributor
 
A set of wiring docs might help. I will leave the tech work to 67Dart273!! For good reason!
 

Attachments

  • 68 Barracuda Factory Wiring REV 2.pdf
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Ok just dove back into it. I ran jumper to starter relay to green wire from vr and it was charging. I jumped two wires from vr together and was charging. Key in on poss ign to pos battery it red .60
 
mikewadkins said:
Ok just dove back into it. I ran jumper to starter relay to green wire from vr and it was charging. I jumped two wires from vr together and was charging. Key in on poss ign to pos battery it red .60
Click to expand...


That is a LOT. The problem with that drop is that the VR will read that and ADD .6 to charging voltage. So it it's trying to regulate "correctly" at 14, you will be charing 14.6 at the battery.

I'd say ground VR, yes, and if no charge, follow the procedure in the manual to check field current draw. It may be "blowing up" VR
 
I cannot see what you are referring to. Might just be overspray. Some of the original VR had a little fuse link internally. They were not meant to be repaired. One thing you could do is reconnect everything "as normal" and again make CERTAIN the VR is grounded. Pull the green wire and insert your meter set up for current and measure current with key on

YOU DID NOT and we need this..unless you are fluent with multimeters..........post the model no or photo of your meter. Measuring current is RISKY if you are unfamiliar ........and can burn out fuses at the least and the meter at the worst
 
By the way when and where did you obtain that VR? So far as I know the auto parts replacements for that are actually solid state internally nowadays
 
Some of the solid state ones look "just like" OEM, and some you can swap covers to "keep" the look. So you did get 'er fixed? But why? WHY did it quit? Re-read my posts and keep in the back of your mind, you might have an alternator field overcurrent issue. Of course it could be the OLD alternator that did this?
 
I think it quit because bolt was loose on vr? The alternator i think was shot. Hardly any resistance when you spin it. Came with car so im slowly working all the bugs out. Has all new qa1 suspension rearend and clutch. Original paint from California. Rust you see is all surface.

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That solid state OEM look is what I use and it has been rock solid for three Years.
 
Ok car has been completely restored paint engine and all. I parked car for little while and my battery died. I replaced battery and was fine drove car all day no issues. Went to dinner with wife and dead battery. The car is no longer charging. I did same as i did last time. Changed vr and still no charge.
Connect vr wires together no change. Im getting 12 v to push on wire at vr. The alt to stud is 12.3-12.6 when running. I checked power to bulk head getting power in car. What am i missing?
 
Did you replace the alternator?
If so, take a photo of the back. One brush should connect to the green wire (feed from voltage regulator). The second brush should be grounded. If they sold you a later style alternator, you'll have to add a ground wire.

Your mechanical regulator (in the photo from 2017) it looks like the fusible links are blown. Yes?
If so, need to figure out why.
That may or may not be related to the current problem.
 
I'll add some pictures since its hard to photograph the back of an alternator on the engine.

In no particular order:
Voltage Regulator's fusible links shown here.
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from 1968 Dodge Service Manual

Those links melt if the rotor draws too much current, or what probably happened, there is a short to ground.
If the green wire touches a ground while the key is in Run position, one or both of those links will melt.
More about that here: Blowing voltage regulators

Alternators with two field terminals like this 'square back'
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..need one of them grounded to work in a pre-70 system, as shown with this 'round back'.
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A pre-1970 'round back' will have one of the brushes grounded to the housing, and so only have one field terminal.
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In a '68 the regulator controls the current feeding the rotor (aka field).
Field is short for Electro-magnetic field. Electrical current through rotor's windings makes a magnetic field.
Alternators create electric power by spinning that magnetic field and inducing current in fixed set of wire windings. The regulator controls how strong the magnetic field becomes by quickly restricting and letting current through as needed.

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edit: An alternator should turn easily when there's no field. So spinning freely is not a problem.
 
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