Only 12.31 volts

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drbrick

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New here guys and i was hoping maybe some of the electrical gurus can help me with a problem.
Here goes-68 barracuda with a 360 eng.,basically stock electrical system for the original 318 that came in car.The problem is that the charging system only puts out 12.31 volts.....Ive changed the alternator and voltage regulator but still same reading.Anything else i should be looking at?
Thanks
 
Not a guru,,But were are you checking the voltage? Check several places.The alt.,stater relay,bulkhead conn. ign.switch...........Jimmy
 
Guys,
I checked the checked the voltage at the battery and back of alt.12.31 running and 12.40 key off.
Also the car starts and runs with the voltage reg unplugged.With the reg plugged in it dies when the neg battery cable is removed.????
Oh almost forgot,10.25V at the ballast resitor with the engine running.
 
drbrick said:
Guys,
I checked the checked the voltage at the battery and back of alt.12.31 running and 12.40 key off.
Also the car starts and runs with the voltage reg unplugged.With the reg plugged in it dies when the neg battery cable is removed.????
Oh almost forgot,10.25V at the ballast resitor with the engine running.
Click to expand...

if it dies when you remove the battery cable, replace your alt.
 
With an alternator, removing a cable is the kiss off death. It is different than a generator.
 
it is a new alternator.The charging problem is why i changed it in the first place.
 
My .02 in 30 years of working on equipment is NO, the alternator will not die if you take off a battery cable. It should be fine IF it was fine before you did it.

Ignition on, car running or not, what is the voltage at the field terminal at the back of the alternator?

If you happen to have a jumper wire, have the connector unplugged for the field wire on the back of the alt. take one of the ends of the wire and connect it to the alternator output stud, start the car, have the voltmeter connected to the alt output also and touch the other end of the jumper to the field terminal of the alternator. This will put the alternator in the "full output" mode and should jump the voltage up quite high. You don't want to do this for a long time but it won't hurt anything. If the voltage doesn't go up I would have to say the alternator is no good.

Now just to check, the alternator should only have the output stud and only one field connection (not two field connections)????
 
drbrick said:
Guys,
I checked the checked the voltage at the battery and back of alt.12.31 running and 12.40 key off.
Also the car starts and runs with the voltage reg unplugged.With the reg plugged in it dies when the neg battery cable is removed.????
Oh almost forgot,10.25V at the ballast resitor with the engine running.
Click to expand...

OK, voltage drops with the engine running means it's not charging at all. Voltage should go up 1 to 2 volts with the engine running dependant on engine speed. Do you have any indication on your ammeter? If no, or discharge, you just confirmed what I said.

360 engine, or ballast resistor voltage does not have any effect here. Did you keep the 69 318 alternator, or did you use the alternator that came with the 360? If you replaced the alternator, did you specify the 69 318 version, or did you go with the 360 and model/year of the donor. Big difference in voltage regulators here and they are not compatible. Also check that your alternator output is making it back to the battery. Problems here can be the ammeter, or the firewall connectors.
check for +12V at the heavy red wire at the alternator with the engine not running. (It should be present). Make sure the important engine to firewall ground strap is intact.

Try this troubleshooting guide;

http://www.mymopar.com/index.php?pid=78

Here's a wiring diagram for your car;

http://www.mymopar.com/downloads/1969/69BarracudaA.jpg
http://www.mymopar.com/downloads/1969/69BarracudaB.jpg
 
A wise man once told me 99% of your charging problems on these old cars are the voltage regulator. But I have seen this caused by a loose belt too. Just my 2 cents. Seth
 
Well GRYZYNX you beat me too it!The car was wired for a pre 1970 motor and that in cludes the post 1970 alternator and transistorized voltage regulator now on the car..So-to sum it up-the 3 post alternator had one field wired to ground.I un grounded the field and tapped into the ignition wire off the ballast and plugged into the 2nd field tap and viola!13.85 volts at idle at the batt.BUt now another problem has arisen-as the RPM's come up,so does the voltage!! 17.7 volts @4500rpm.Maybe the new voltage reg is bad?Or the new alt?
Also-the plug for the Volt reg has 3 wire coming out of it blue,black and tan i think-it looks like the tan wire was hooked up to a suppressor which was bolted to the hold down on the reg.Does this sound right.
 
drbrick said:
Well GRYZYNX you beat me too it!The car was wired for a pre 1970 motor and that in cludes the post 1970 alternator and transistorized voltage regulator now on the car..So-to sum it up-the 3 post alternator had one field wired to ground.I un grounded the field and tapped into the ignition wire off the ballast and plugged into the 2nd field tap and viola!13.85 volts at idle at the batt.BUt now another problem has arisen-as the RPM's come up,so does the voltage!! 17.7 volts @4500rpm.Maybe the new voltage reg is bad?Or the new alt?
Also-the plug for the Volt reg has 3 wire coming out of it blue,black and tan i think-it looks like the tan wire was hooked up to a suppressor which was bolted to the hold down on the reg.Does this sound right.
Click to expand...


Are you able to post a picture of the regulator??? Most regulators only have two wires to them.

if you can't post a picture look at this thread, the 7th post down had a picture of the electronic voltage regulator, two wires. The blue gets connected to a keyed battery lead such as the hot side of the ballast resistor. The green wire goes to one field terminal on the alternator. The other filed terminal of the alternator goes again to the hot side of the ballast resistor. You have to make sure the regulator has a very good ground!

http://www.forabodiesonly.com/mopar/showthread.php?t=113775
 
nothingbutdarts said:
Are you able to post a picture of the regulator??? Most regulators only have two wires to them.

if you can't post a picture look at this thread, the 7th post down had a picture of the electronic voltage regulator, two wires. The blue gets connected to a keyed battery lead such as the hot side of the ballast resistor. The green wire goes to one field terminal on the alternator. The other filed terminal of the alternator goes again to the hot side of the ballast resistor. You have to make sure the regulator has a very good ground!

http://www.forabodiesonly.com/mopar/showthread.php?t=113775
Click to expand...

I will get a photo of the setup this afternoon and post it up.But it is definatly 3 wires from the reg.Also i will check the grounding in alll the suspect places.
Will a grounding issue cause the voltage to spike at higher RPM?
Thanks for all the help
 
ok-heres a couple of pics.The tan colored wire has voltage when keyed or running only(between 12.4 keyed and higher when running).
The alternator miidle field terminal has no juice period.The other field has plenty of voltage when keyed(12.4) and 13.8 or higher depending on rpms of engine(up to 17.6).
The wierd thing with the voltage reg is that it only has 2 terminals and the same under the plug with the 3 wires.And the blue and green wires coming out of the plug line up with the terminals on the regulator....
Man- am i stumped and frustrated.
Any help is really appreciated.
 
That is not a factory regulator. It must be some sort of aftermarket. I can't really see the tan wire you are talking about unless it's on the capacitor looking thing on the left side of the regulator.

The factory regulator looks like the picture on the thread I posted in my last posting to you. Look at the #7 post to see what a factory regulator looks like.

However, If there is a brand name on the regulator which I believe I see a tag on it you might call the manufacturer.

Where do the current wires on the alternator go to know? It looks like on the output stud of the alternator there are more than one wire?

IF, it were a factory regulator, you would have 1 power wire coming from the ignition switch "run" position to the ballast resistor, spliced (actually a welded splice) off that same wire would be two other wires, one of them would go to the blue wire on the regulator and the other would go to one of the field terminals on the alternator. Then the green wire on the regulator would go to the other field terminal on the alternator and it should work as long as the regulator has a good ground to the system. That's how the factory one was wired. You might try just using the two (blue/green) wires on your regulator and hooking them up like I explaned and see what happens.
 
Well sir-This thing is a mess.The extra red wire on the output of the alt comes fromt the starter relay? so the alt has power all the time.this wire was added by someone else.
I believe that the wiring harness is jacked up and i basically need to start from scratch.
I will investigate further tommorrow and i am going to start with the wire from the run posistion on the ign switch and then follow your directions.
Question though Should i bypass the ammeter?it does not appear to work anyhow.
Also the miidle field on the alt does nothing that i can see with my volt meter-could it be a grounded field?
Oh and look again at the pic-It shows 3 wires coming out of the plug,and i will change the voltage reg out-but i have no idea if i should ask for a 70's or later reg or what.

Thanks again.
P.s- know any one in nor-cal that could look at this mess?
 
Oh and the blue wire does not like to be hooked up to the middle fld terminal.Lots of sparks and the wire starts to get real hot-almost like that terminalis a ground.
 
Time for a rewire it looks like. That regulator is a 70's on unit. It should be all wired correctly. From the link someone else gave you, it should be wired like this

pic3.gif


Good luck!
 
drbrick said:
Oh and the blue wire does not like to be hooked up to the middle fld terminal.Lots of sparks and the wire starts to get real hot-almost like that terminalis a ground.
Click to expand...


Before you hook any field terminals to the alt. unhook both wires currently hooked to the field terminals.

Take an ohmmeter and check between both field terminals, it should be close to zero ohms. Then leave one of the test leads on one of the field terminals and touch the other test lead to the case of the alternator. You should get infinate reading on the ohmmeter. If you do get a low (close to zero reading) than something is shorted in the alternator.

If it tests OK as far as not being shorted than retry hooking the blue field wire up again with out a wire connected to the second field terminal and see if it sparks and gets hot.
 
drbrick said:
Well sir-This thing is a mess.The extra red wire on the output of the alt comes fromt the starter relay? so the alt has power all the time.this wire was added by someone else.
I believe that the wiring harness is jacked up and i basically need to start from scratch.
I will investigate further tommorrow and i am going to start with the wire from the run posistion on the ign switch and then follow your directions.
Question though Should i bypass the ammeter?it does not appear to work anyhow.
Also the miidle field on the alt does nothing that i can see with my volt meter-could it be a grounded field?
Oh and look again at the pic-It shows 3 wires coming out of the plug,and i will change the voltage reg out-but i have no idea if i should ask for a 70's or later reg or what.
Click to expand...

Ok, a couple of things I noticed in your comment... the "new" red wire running to the starter relay is a common upgrade to help eliminate the poor charging that comes with our design of our car. Read this http://www.allpar.com/history/mopar/electrical.html. See 4. and 5. specifically.

It should have some sort of fusible link or fuse on it to keep from burning anything up. It basically bypasses the voltage going through the bulkhead connector and amp gauge. The main feed now going through the bulkhead just provides power to your interior and lights. Helps take off some of that load. Your amp gauge will not read right (but you might detect a little movement).

I would really clean up some of that wiring at the alternator. Some soldered connections and heat shrink will really improve the performance and looks of that wiring.
 
nothingbutdarts said:
Before you hook any field terminals to the alt. unhook both wires currently hooked to the field terminals.

Take an ohmmeter and check between both field terminals, it should be close to zero ohms. Then leave one of the test leads on one of the field terminals and touch the other test lead to the case of the alternator. You should get infinate reading on the ohmmeter. If you do get a low (close to zero reading) than something is shorted in the alternator.

If it tests OK as far as not being shorted than retry hooking the blue field wire up again with out a wire connected to the second field terminal and see if it sparks and gets hot.
Click to expand...

OK good info here.I will work on it this eve.Qustion though-The 2 field hookups on the Alt. are not marked +,-....Does it matter which field the blue wire gets hooked to?Like i said the blue wire does not like being hooked to the center FLD terminal,but its ok on the outside FLD terminal.
Thanks and i will post my results this eve.
 
drbrick said:
OK good info here.I will work on it this eve.Qustion though-The 2 field hookups on the Alt. are not marked +,-....Does it matter which field the blue wire gets hooked to?Like i said the blue wire does not like being hooked to the center FLD terminal,but its ok on the outside FLD terminal.
Thanks and i will post my results this eve.
Click to expand...

No, there is no +,-. However the two field terminals in reality are just one very very long piece of wire wrapped around the rotor, but insulated from it electrically.

Make sure both wires are disconnected from the field terminals, ohm's check the two field terminals together as I mentioned and then double check that, with one ohmmeter lead connected to one of the field terminals you have no continuity to the outter case! Infinate resistance is what you are looking for as far as grounding out to the case.
 
rob_robinson87 said:
Ok, a couple of things I noticed in your comment... the "new" red wire running to the starter relay is a common upgrade to help eliminate the poor charging that comes with our design of our car. Read this http://www.allpar.com/history/mopar/electrical.html. See 4. and 5. specifically.

It should have some sort of fusible link or fuse on it to keep from burning anything up. It basically bypasses the voltage going through the bulkhead connector and amp gauge. The main feed now going through the bulkhead just provides power to your interior and lights. Helps take off some of that load. Your amp gauge will not read right (but you might detect a little movement).

I would really clean up some of that wiring at the alternator. Some soldered connections and heat shrink will really improve the performance and looks of that wiring.
Click to expand...

Thanks for that link Rob.Very helpful.That would explain the 2 wires going to the output of the Alt.So if i understand this correctly-the big red wire from the relay should be the only wire i need on the output stud of the Alt?
Oh and the wiring will get cleaned up(again) when i get these issues straitened out.O:)
 
No no no... you still need the main feed to go inside the car for power for all the interior and lights (that will be the old wiring). Basically you end up with two routes, one that goes through the bulkhead, inside for your accessories (including gauges, radio, lights, etc.) and then the new loop that bypasses the interior and goes straight to the battery for charging. They both end up at the starter relay. You just relieved having ALL the power having to go through the bulkhead.

See the diagram I modified.. the red wire from the alternator is that "new" wire. Make sense?
 
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