New Member with charging issue

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68Nwprt

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I just read a very informative thread while searching google trying to get my charging system sorted out, where a member was having charging issues and I am hoping I could get some help. This is the thread.
http://www.forabodiesonly.com/mopar/archive/index.php/t-256694.html

Anyway Iv'e spent the last two weekends fighting with this charging problem on my 68 Newport, and I know this is the A body forum but I am at the point where I need to get help anywhere I can. Couldn't seem to get to charge over 12.3V, when running until I read the stated thread and connected one field to bat+ and the other to bat ground and alt charges at 14-16V. so with this test I know the alt is working. Connect VR and back to 12.3V. Now need some help getting the VR sorted out. I did the 70 and up, upgrade and am using a new sq.back atl. and a new VR. Would appreciate any help. Thanks.
 
So you ARE using the 70 / later "flat" regulator?

Should be hooked up like this...........

Dual_Field_Alternator_Wiring.jpg



In reality you only need to run one new wire.....from the "ignition run" blue down to the second field terminal of course 'as usual' the VR MUST be grounded.

The two wires at the new VR could be the old ones, re-used. If you are using a "junkyard" VR connector, you might suspect that.

The top - end of the ballast resistor is the "jump off" point. That is "ignition run" feeding one wire to the field, and the other (factory) runs to the IGN terminal of the VR.

NOTICE that the IGN terminal of the VR is the middle terminal, and the FIELD is on the far right. These are NOT reversible
 
Using the 70 later flat VR. I am going to check the wiring and get back to you . Thanks for the help so far.
 
OK,I checked the wiring and it appears to be correct. Still 12.3 V at battery with engine off and the same 12.3V with engine running.
 
You are absolutely certain the VR is grounded?

Let's make some simple checks.

With key on, engine stopped, disconnect the VR connector. You should show "same as battery" at both connector terminals.

Pull the blue field wire off at the alternator. The GREEN terminal at the VR connector should go dead.

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You have a multimeter that can measure 10 or 20 amps? Don't know? Post brand / model, or a photo.

Set the meter up for high range amperage (current)

With key in 'run' pull the VR connector off the VR. Ground one probe of your meter. CAREFULLY pick the GREEN wire in that (terminal closest to "end" of connector) and read that. You should measure field current of the alternator, somewhere 3--6 amps

If not, move down to the alternator. Hook the meter between the green field alternator terminal and ground, still in "current". you should again measure field current.

If not, set your meter back up for voltage

Take a clip lead and ground the exposed field terminal you were just accessing. In subdued lighting you should see a small spark. Measure voltage on the BLUE field lead which should still be connected. This should measure very close to "same as battery" whether the clip lead is grounding the opposite terminal or not.

To be clear:

The alternator field terminals are interchangeable, I'm referring to factory wire colors

So green is the return to the VR

Blue is "switched" ignition run voltage.

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"Work" the VR connector in/ out and feel it for tightness. Inspect it internally for corrosion. Is this a new VR connector or junkyard?
 
VR is grounded, Checked with resistance test.
With key on:
from ground on bat to each VR terminal I get same as battery 12.5.
W/blue disconnected from alt., green at VR reads 4.6V.
Checking with sperry DM4100A multi meter.

No luck testing for amperage.

With grn terminal at alt grounded with key on:
12.5 at Bat.
11.2 blue at alt.
Also have large spark when connecting Bat. ground to green on alt with key on.
 
The 11.2 shows a lot of voltage drop, but it still should be enough to run the system.

I'm not sure how you obtained the 4.6, that may be meaningless

"Large spark"? How large? You should see a spark in subdued lighting, I doubt in bright lights or daylight. You are talking about (normally) a 3-6A load, there
 
To measure field current with your meter:

MJJD-411.JPG


Turn the switch to bottom left corner, "10A"

Leave the black probe in the COM jack and move the red probe to the far right jack, "10A"

Be careful, as an ammeter is a SERIES device, and a mistake can hurt the meter. It may or may not have an internal fuse

EDIT found the destruction manual online. Page 15 says: .......so the amp scale is NOT fuse protected
 

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With key on, from bat.ground to VR green = 5.2 amps

With key on, battery ground, to grn. at Alt. medium size spark, easily visible in daylight.
 
I often say, LOL, "new does not mean functional"

This is more true than ever, with chineseoated parts
 
New VR going in, in the AM. Thanks for all your help so far. I will be real happy to get this sorted out. Whatever it takes. BTW the VR connector is also new.
 
Check the bulkhead connectors. They are a weak link in the charging system.

Battery to bulkhead to ammeter, ammeter to bulkhead to alt.

With age resistance goes up and the connections overheat and melt the bulkhead in both locations.

Best to wire bat to alt directly and use a volt meter to monitor the system instead of the ammeter. Also add a maxi fuse at the battery end.

The Bat wire also supplies the ignition switch so run a second maxi fuse near the bat and wire directly to the Ignition switch.

BTW if you added a 60 amp alternator the ammeter can't handle the load for very long.
 
Thanks. I checked and cleaned the bulkhead connectors,there were no over heated connections. When doing a amp meter bypass, is it best to dis connect both wires from the meter and connect them together or just use one terminal on the meter and put both wires onto there?

"Best to wire bat to alt directly and use a volt meter to monitor the system" Leave existing wire on Alt or no?
 
New VR installed and we are charging @ 13.8-14.0 Volts. :blob:
I can't thank you enough. Your systematic evaluation is spot on. For now I have the amps meter bypass as to keep things safe. Next up will be the MAD conversion, then the tail lights to sort out. Thanks again and I will post up a few pics when I get a chance.
 
Another case solved by 67dart273. Great job as usual .
 
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