Hey it's a 73 scamp 318/904 mostly stock, alt not charging. Sorry if stupid question but I noticed I don't have a voltage regulator, could this cause it? Also a test light shows power to all 3 wires at alt and power at female hookup for regulator. Thanks guys.
Alternator not charging
- Thread starter dru34
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67Dart273
Well-Known Member
You HAVE to have a regulator, it looks like this:
unless someone removed it. Find it, remove it, scrape the firewall and mounting flange and remount, making absolutely certain it is grounded.
If that does not fix the problem, make a couple of quick checks
Pull the green field wire off at the alternator, turn the key to run. You should measure battery voltage at both field terminals. Now take a clip lead and ground the alternator terminal which is now unhooked. Not the wire---the alternator terminal.
This will send full 12V through the field to ground. Now start the car and bring up RPM and see if it charges.
unless someone removed it. Find it, remove it, scrape the firewall and mounting flange and remount, making absolutely certain it is grounded.
If that does not fix the problem, make a couple of quick checks
Pull the green field wire off at the alternator, turn the key to run. You should measure battery voltage at both field terminals. Now take a clip lead and ground the alternator terminal which is now unhooked. Not the wire---the alternator terminal.
This will send full 12V through the field to ground. Now start the car and bring up RPM and see if it charges.
67Dart273
Well-Known Member
Nope, 70/ later, but I would not buy a regulator until you know the problem............
Did you just buy the car? Did someone remove the regulator? You DO have a factory Chrysler type alternator?
More details.
One thing I did forget, there IS an aftermarket add-on regulator that mounts right on the rear of the alternator. Powermaster uses similar
Here's a Powermaster, it's the little chrome box at lower right. You can see the wire pigtails hooked to the rear
Did you just buy the car? Did someone remove the regulator? You DO have a factory Chrysler type alternator?
More details.
One thing I did forget, there IS an aftermarket add-on regulator that mounts right on the rear of the alternator. Powermaster uses similar
Here's a Powermaster, it's the little chrome box at lower right. You can see the wire pigtails hooked to the rear
BillGrissom
Well-Known Member
Disconnect the two field terminals (spade connectors, Packard 57 type) from the factory wiring. Provide your own +12 V direct from BATT+ & BATT-, using 16 awg or thicker wire. Doesn't matter which field terminal is positive. Also run a jumper from the body of the alternator to BATT- (i.e. don't rely on the path thru engine block). It should output current then, assuming the path into & out of the cabin thru the ammeter in your instrument cluster works (verify w/ ohm-meter).
In my old Mopars, I recall 2 alternator problems. One was the body wasn't electrically connected to the engine block (sand-paper fixed that). The other was that a brush was totally worn down. The copper ring inside had a deep groove worn. Must have been the original 1965 alternator (problem was in 1992).
In my old Mopars, I recall 2 alternator problems. One was the body wasn't electrically connected to the engine block (sand-paper fixed that). The other was that a brush was totally worn down. The copper ring inside had a deep groove worn. Must have been the original 1965 alternator (problem was in 1992).
ok I will try that, BTW when I cranked the car and had it at idle my digital multimeter read as follows black large wire-(10.6 V) blue wire hooked to middle terminal-(9.4 V) green wire hooked to far end (0.7 V). Does that tell yall anything? BTW I have a square back ALT that came with my car(not sure if working) should I hook that one up instead to see if that will make a difference? thanks again.
View attachment IMG_0589.jpg
this is the ALT on it now, this is ofcourse before I hooked up the green wire to the far end terminal. Maybe this will help.
this is the ALT on it now, this is ofcourse before I hooked up the green wire to the far end terminal. Maybe this will help.
64ragtop
Well-Known Member
You MUST have a voltage regulator somewhere in that circuit or your alternator will not charge. The 10.6 volts on the alternator output wire clearly shows that
the alternator is not charging. (At least you have a volt meter!) The readings on the blue and green wires are about right without a functioning voltage regulator.
Refer back to the post from 11-8 from 67Dart273 and either find your regulator and replace it or install one like he showed in his post. Putting the other alternator in will not help. You NEED to have a functioning voltage regulator before the alternator can charge! (HINT - HINT!!!)
BC
Sorry I didn't clarify but those readings were after I installed the new VR, lol. So what does that mean? Thanks again
64ragtop
Well-Known Member
In THAT case, I'd try that other alternator IF it seems to turn OK and has the same connectors. If that doesn't help, take both to a generic autoparts store and have 'em tested.
These diagrams might help ya verify your wiring.
http://www.mymopar.com/downloads/1976/76ValiantA.jpg
http://www.mymopar.com/downloads/1976/76ValiantB.jpg
They have some discrepancies from the Factory Service Manual drawings, but they're better than flyin' blind!
I highly recommend you get a Factory Service Manual, NOT one from the parts store.
BC
pulled dash to look at ammeter wires, all looks good with no corrosion or burn marks, so I guess I can leave that alone as long as I don't go higher the 50 amps of an ALT, is that right?
BTW I grounded the GRN terminal and the readings were the exact same as before.
Did Test by probing BATT NEG and then POS on ALT case and it read 0.1 to 0.2 max.
Did test by probing POS BATT and then while probing large BATT terminal at ALT and read 1.0 to 2.0 volts, what does that mean?
BTW I grounded the GRN terminal and the readings were the exact same as before.
Did Test by probing BATT NEG and then POS on ALT case and it read 0.1 to 0.2 max.
Did test by probing POS BATT and then while probing large BATT terminal at ALT and read 1.0 to 2.0 volts, what does that mean?
67Dart273
Well-Known Member
Not clear to me whether you ever found an installed regulator. This is troubling, because either it's missing, or you have not found it, or someone has installed an aftermarket regulator like the Power Master I mentioned earlier.
YOU NEED to resolve this part of the question. You cannot do any troubleshooting until you figure out "whut you have" for a regulator.
YOU NEED to resolve this part of the question. You cannot do any troubleshooting until you figure out "whut you have" for a regulator.
I'm sorry I didn't clarify but I purchased the black VR that you posted a picture of earlier and installed it. The previous owner didn't have one at all. With that being said my last couple of post were test I conducted AFTER new VR was installed(mounted to fender well, I sanded the fender well and bottom of VR to bare metal it has good ground)
67Dart273
Well-Known Member
OK. Review this simplified diagram:
No, driving it with no regulator will simply not charge.
Ignore all the ignition stuff to the left side below the ballast resistor.
Here's what you have. From the ignition switch (through the firewall) you have the ignition "run" feed which feeds power to the top of the ballast resistor, and BRANCHES OFF to the right and feeds ONE FIELD TERMINAL of the alternator as well as the IGN terminal of the regulator. Look at the drawing of the regulator. That plug is drawn just as if you were looking at the front of the regulator.
So with key in "run" check you should have "same as battery" voltage at the blue field wire of the alternator, and at the "I" terminal of the regulator.
Now with everything hooked up properly, remove the green field wire from the alternator. Again with the IGN switch in "run" you should have "same as battery" at the alternator field terminal from which you just disconnected the green wire.
Now take a clip lead and GROUND that alternator field terminal.
REcheck--------you should still have battery on the blue field wire, while CONNECTED normally to the alternator.
If so, start the car, bring up RPM and see if it charges
If not, check voltage at the great big output stud of the alternator. If the voltage there is quite high when bringing up RPM, say, way over 15V, and no charge shown on the ammeter, you have a wiring problem in the charging wire/ firewall connector/ ammeter circuit
If voltage is LOW, say, 12V or lower, then the alternator is NOT charging. You have an internal problem.
If however the alternator DOES charge in this test, you may have a regulator field wiring problem, or a bad regulator, or bad connection at the regulator connector.
IF the alternator DOES charge in the above test, then do the following:
Hook everything back up normal.
Disconnect the regulator connector, and devise a way to jumper the two connector wires together. Small screws work, with a clip lead. Now, disconnect the BLUE alternator field wire, and ground that alternator terminal. With the key in "run" you should now have battery at the field terminal with the GREEN wire connected.
Again start the car and see if it charges, when RPM is brought up.
BE CERTAIN that you have the regulator GROUNDED. Clean the firewall and regulator mounting flange, be sure the bolts are tight, and use star lock washers.
No, driving it with no regulator will simply not charge.
Ignore all the ignition stuff to the left side below the ballast resistor.
Here's what you have. From the ignition switch (through the firewall) you have the ignition "run" feed which feeds power to the top of the ballast resistor, and BRANCHES OFF to the right and feeds ONE FIELD TERMINAL of the alternator as well as the IGN terminal of the regulator. Look at the drawing of the regulator. That plug is drawn just as if you were looking at the front of the regulator.
So with key in "run" check you should have "same as battery" voltage at the blue field wire of the alternator, and at the "I" terminal of the regulator.
Now with everything hooked up properly, remove the green field wire from the alternator. Again with the IGN switch in "run" you should have "same as battery" at the alternator field terminal from which you just disconnected the green wire.
Now take a clip lead and GROUND that alternator field terminal.
REcheck--------you should still have battery on the blue field wire, while CONNECTED normally to the alternator.
If so, start the car, bring up RPM and see if it charges
If not, check voltage at the great big output stud of the alternator. If the voltage there is quite high when bringing up RPM, say, way over 15V, and no charge shown on the ammeter, you have a wiring problem in the charging wire/ firewall connector/ ammeter circuit
If voltage is LOW, say, 12V or lower, then the alternator is NOT charging. You have an internal problem.
If however the alternator DOES charge in this test, you may have a regulator field wiring problem, or a bad regulator, or bad connection at the regulator connector.
IF the alternator DOES charge in the above test, then do the following:
Hook everything back up normal.
Disconnect the regulator connector, and devise a way to jumper the two connector wires together. Small screws work, with a clip lead. Now, disconnect the BLUE alternator field wire, and ground that alternator terminal. With the key in "run" you should now have battery at the field terminal with the GREEN wire connected.
Again start the car and see if it charges, when RPM is brought up.
BE CERTAIN that you have the regulator GROUNDED. Clean the firewall and regulator mounting flange, be sure the bolts are tight, and use star lock washers.
"If voltage is LOW, say, 12V or lower, then the alternator is NOT charging. You have an internal problem." What do you mean internal problem? Meaning bad alternator?OK. Review this simplified diagram:
No, driving it with no regulator will simply not charge.
Ignore all the ignition stuff to the left side below the ballast resistor.
Here's what you have. From the ignition switch (through the firewall) you have the ignition "run" feed which feeds power to the top of the ballast resistor, and BRANCHES OFF to the right and feeds ONE FIELD TERMINAL of the alternator as well as the IGN terminal of the regulator. Look at the drawing of the regulator. That plug is drawn just as if you were looking at the front of the regulator.
So with key in "run" check you should have "same as battery" voltage at the blue field wire of the alternator, and at the "I" terminal of the regulator.
Now with everything hooked up properly, remove the green field wire from the alternator. Again with the IGN switch in "run" you should have "same as battery" at the alternator field terminal from which you just disconnected the green wire.
Now take a clip lead and GROUND that alternator field terminal.
REcheck--------you should still have battery on the blue field wire, while CONNECTED normally to the alternator.
If so, start the car, bring up RPM and see if it charges
If not, check voltage at the great big output stud of the alternator. If the voltage there is quite high when bringing up RPM, say, way over 15V, and no charge shown on the ammeter, you have a wiring problem in the charging wire/ firewall connector/ ammeter circuit
If voltage is LOW, say, 12V or lower, then the alternator is NOT charging. You have an internal problem.
If however the alternator DOES charge in this test, you may have a regulator field wiring problem, or a bad regulator, or bad connection at the regulator connector.
IF the alternator DOES charge in the above test, then do the following:
Hook everything back up normal.
Disconnect the regulator connector, and devise a way to jumper the two connector wires together. Small screws work, with a clip lead. Now, disconnect the BLUE alternator field wire, and ground that alternator terminal. With the key in "run" you should now have battery at the field terminal with the GREEN wire connected.
Again start the car and see if it charges, when RPM is brought up.
BE CERTAIN that you have the regulator GROUNDED. Clean the firewall and regulator mounting flange, be sure the bolts are tight, and use star lock washers.
Well got battery fully charged and had everything hooked up except the GRN terminal. Grounded the GRN terminal and still didn't charge. I also tested the Voltage at the Large black terminal of the alternator and at idle it was reading 11.3.
So I guess its an "internal problem". I do have a square back alternator that somebody gave me. So I will swap it out and see it that fixes it.
So I guess its an "internal problem". I do have a square back alternator that somebody gave me. So I will swap it out and see it that fixes it.
64ragtop
Well-Known Member
If it was easy, dru, everybody would be doin' it!
67Dart273
Well-Known Member
If you checked that you have battery voltage on the blue field wire with ignition in "run" that is exactly what I would do next
Update: tested the two ALT I had at advanced auto, both had bad stators. Bought new one square back 65 amp, which is for a 73 scamp 318. Hooked up new one, still no charging, however a few differences. First is that at idle my ammeter needle is slightly above the middle marker also under acceleration there is a slight discharge, is that normal. Second is with my multimeter on the battery post and I push the throttle the meter goes up a couple of tenths, it did not do this before. I'm guessing wiring now?
67Dart273
Well-Known Member
"Goes up a couple of tenths." From what to where to whom? I don't know if it's going from .00000000005 volts to .2 volts, or from 14 to 14.2
Frankly I find it difficult to believe you have two with identical problems. Very unlikely. Just how did you " test " them?
What does voltage run AT THE BATTERY with the engine running at a good fast idle?
Frankly I find it difficult to believe you have two with identical problems. Very unlikely. Just how did you " test " them?
What does voltage run AT THE BATTERY with the engine running at a good fast idle?
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