Ammeter Battery overcharge

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4spdragtop

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Hi all. Ammeter is showing "high voltage" and is "jumpy". Im in the middle of performing tests. I have multimeter.
Currently running 273 Mopar elec ignition. Orange box. All stock wiring other than for elec ign.
Stock coil, stock gauges EXCEPT aftermarket coolant temp and oil psi. Dash ones are unhooked. I haven't done the MAD electrical yet but its in the future.
I picked up a NEW voltage regulator today. Standard # VR125. (See pic)
But the connections are different than my current one?? I gave description of 73 dart for VR as I figgered that would give me electronic ign VR?? But connections are definitely different.
Im checking a few things now and will provide more info/results if need be.

Pics attached
Thanks
Steve

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The pic of firewall is to show where VR was mounted. I know shitty ground right? Ran great 4 years now though. Maybe time ran out on shitty ground?. New battery 2 weeks ago and new alternator 2 years ago.
Oh what started this was I could smell an odour and I knew right away to check gauges. Thats when I noticed an overcharging on factory ammeter.

Thanks all
 
They gave you the electronic regulator instesd of the older points style. What is weird is that I thought 73 already had the electronic regulator.
 
I have the MP elec ignition so no points. Is my current VR ( see pic) a points style? Its the same one since Dad bought the car in 2012.
So it doesn't make sense? Car has been super reliable with very few issues. Also new M&H engine forward harness. Takes up 2 of the 3 spots in bulkhead, so im assuming thats good.
I added an extra ground wire from reg mount bolt directly to battery -ve ( see pics) I also got dremel out and ground paint off mount holes.

With car idling I have 12.93 directly off battery posts.
At idle and from battery -ve to VR case I have 8 mV.
At 2500 rpm battery -ve to VR case 17mV.

Any help appreciated
Thanks
Steve
 
Thanks for the link ValiantOne. In that thread it reads like in order to switch I would need a different style alternator? ?
Here's pics of current alternator thats approx 2 years old. 2 connectors, green one (looks like wires cracked but its not thats heatshrink)
The other connector has violet and black wires.
I would need a 2 field alt correct?

Thanks

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Up until a couple days ago the ammeter gauge was always steady in the middle.
1st pic car running in park approx 2500 rpm
2nd pic in park and idle
3rd pic in drive brakes on and in drive
4th pic driving approx 50 mph and around 2800 rpm

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Also another test
Car turned off green wire to back of alternator off had continuity from tab where green wire connects to and battery -ve.
No continuity from green wire to battery -ve.
 
I am no expert but sometimes these old mopars don't get a full signal voltage to the regulator. The regulator sees that as a low battery and sends more juice via the alternator, which can overcharge and burn up the battery.

Yes I believe you do have to go with the 3 wire alternator when you do the electronic vr upgrade. I did. Maybe there is another way I am not aware of though. I had a 3 wire spare so I used it.

Best

CE
 
2 tests I did this morning.
key in run but engine off. Measured 0.3V from green fld connection on VR to VR case.
Same on blue ign connector to VR case.

Not sure how to diagnose this, but read these tests should be performed.
Is there a translator in the house?
 
Steve, I wish I had answers for you,but I don't. I always follow these electrical threads cuz that's my weakness. Usually Del and a couple other guys on here seem to be pretty knowledgeable on this kind of stuff. Hope you get it figured out....
 
BTW, yes you do have the older style alternator. On my '67 I changed over so I could use the squre back alternator with the newer style VR. Like in the top pic.
 
From what I can tell your 67 has the early regulator, alternator system. The early alternator has one field terminal connected to the alternator case marked ground. The other field terminal connects to the green wire that goes to screw lug on regulator. The early regulator conducts voltage to that terminal when IGN terminal is below about 13.8V, and not when above. It chatters about doing that at a fast rate. In your case of over charge, the transistor is shorted on ... and that is permanent.

You need an early style replacement regulator. The later style regulator shown in your first picture works by pulling the field terminal low to ground, and with a late alternator, the other field terminal is supplied by IGN. If a new style regulator is used with old style alternator, one field terminal is ground at alternator, the other is grounded by regulator, so field is never energized, and alternator will not function.
The picture of the spare alternator looks like the field brush terminal is broken off. Fix that by easy brush replacement, if you ever need to use.
 
Thanks Larry, yeah electrical is one of many weakness. I know these tests are pertinent but no idea the diagnosis. ..lol
 
If you want to test the old regulator, use Ohm meter between IGN and Field terminals, with regulator out of circuit. The resistance should be in megohms, of low resistance transistor is failed, regulator bad.

This test will not work on mechanical relay style regulators.
 
Thanks Kit! I just got back from 5hr trip in it. Not 100% comfortable with it. Idle is now lousy. Not sure if its related or not. Gotta get a connector for the newer style VR.
I will perform checks sometime this week and report back.
Thanks for the input!
 
I assume you are driving with "high voltage "? A problem like that needs immediate attention.

My guess is 5 hours of driving would have cooked the battery. The problem might be poor bulkhead connections. That is checked by using a voltmeter and measuring voltage at IGN terminal with engine running. If it is about 13.8V, but battery voltage is higher (^14.2V) , the difference is the voltage drop. The drop should only be a few tenths. The regulator tries to regulate the voltage at IGN, by switching the field on as necessary. Since the alternator delivers the power connectors, thru the amp gauge and back to battery, voltage drops there result in the alternator voltage running high, to achieve the desired voltage at IGN.
 
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FWIW Steve, I have this VR in my MP conversion..................
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From the MP book............

MPreg2.gif
 
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I just had to make new engine harness for my 74. It has the square back alt and electronic VR and the blue wire is hot and also feeds the coil and field on the alt if it helps. The green went to the VR top pin and the blue to the VR lower pin if it make sense?
 
Ok so I bought this VR. original look with modern guts. It still connects the same as my 67 style. No mods required. Still the same issue. Needle jumping up with higher rpms.
Im cleaning up some bulkhead connections and will report back.
Curious how my newest VR can be hooked up like original but function like a modern one??
Thanks all
Steve

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The new regulator shown hooks up just like old one. A PNP, transistor switches the power instead of a relay. Your problem is likely a drop in the bulhead connector, the drop is found by measuring battery voltage to IGN terminal on regulator. There should only be a few tenths of volt drop.
 
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