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68red440
enthusiast


Reged: Dec 07 2003
Loc: Cincinnati, OH
100A 3-wire alt, regulator or no regulator?
      #6560917 - Thu Mar 31 2011 06:22 PM

This winter on my Coronet I added electric fans so I upgraded to a 100A tuff stuff alternator with an internal regulator. On the back of the alternator, I attached the ground wire to the case per the instructions. I added an 8Ga cable from the alternator stud to the starter relay. I left the voltage regulator in the car, overlooking the fact that the alternator already had one. So when I drove it, the volt meter inside the car was oscillating from 14 to 16 the entire time. Before the upgrade the voltage would stay steady at 14.7, and that is how I drove it the past few years.

Last night I removed the regulator from the firewall, and jumpered across the regulator connections. I also removed the regulator ground strap and left it off. Tonight with the engine running, the volt meter climbed to 18V and stayed pegged.

The regulator is one that looks stock, but is electronic. It worked great for years with the 60A alt.

Did I miss something in the wiring? I don't need an external regulator, do I?

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Theorio1025
member


Reged: Jul 20 2009
Loc: Staten Island, NY
Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
      #6560942 - Thu Mar 31 2011 06:28 PM

No if it is internally regulated you have no need for the external regulator

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Yancy Derringer
mopar


Reged: Oct 20 2010
Loc: Montana
Re: 100A 3-wire alt, regulator or no regulator? [Re: Theorio1025]
      #6561019 - Thu Mar 31 2011 07:04 PM

Quote:

No if it is internally regulated you have no need for the external regulator




I just got back from their @#mn poor website, and I don't believe you are correct. The only instructions for the 7509 series (if that is what he has) shoes a "field grounding kit" intended to convert isolated field alternators to use the 69/ earlier regulator.

The fact that after he bypassed the regulator, it is obviously overcharging tells me he needs an external regulator.

I would say your original problem is either a voltage drop issue in the harness/ bulkhead connector, a regulator grounding problem, or a defective regulator

Hook up your regulator as you had it and try the following tests:

Start the car, get the battery "up," and make these tests at simulated "medium cruise" engine RPM. Make the tests once with all accessories off, then again with lights, heater, or other loads on

With the engine running "med. cruise" take your meter and stick one probe directly onto the battery negative post. Stick the other directly onto the regulator mount flange. You are looking for a very low voltage reading, zero is perfect. Anything over .2V (two tenths of a volt) is too much. If it is over this, improve the ground between the battery and the regulator

Now check the hot side of the harness. What you are checking for here is the voltage drop from the battery, through the bulkhead, harness, to the connector at the ign switch, through the switch, back out the connector, harness, bulkhead, and to the regulator.

Stick one probe directly onto the battery positive post, the other as close as you can to the regulator IGN run (dark blue, normally) terminal. Probably the ignition ballast resistor connection is close as you'll get.

As with the ground, you are looking for a very low reading, and anything over .2V is too much. You could have an ignition switch going TU, a loose connector, or problems with the bulkhead connector, or other harness problems.

Also go over your main heavy charging wire, check for poor connections, heat, melting, etc.

If none of this cures the pulsing problem, try a different "high quality" regulator.


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68red440
enthusiast


Reged: Dec 07 2003
Loc: Cincinnati, OH
Re: 100A 3-wire alt, regulator or no regulator? [Re: Yancy Derringer]
      #6561125 - Thu Mar 31 2011 07:48 PM

Thanks Yancy,
Before I run these tests tomorrow night, a couple questions...
Could it be that the internal regulator is not working? Am I bypassing it somehow - maybe with the field grounding wire on the alt case?

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Yancy Derringer
mopar


Reged: Oct 20 2010
Loc: Montana
Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
      #6561487 - Thu Mar 31 2011 09:48 PM

I would first make sure "what you have." I cannot tell for certain from their website. Maybe call 'em and be sure. If there's some way to get down in there an post a clear picture of the rear of the case, I could probably tell just by looking

They do show a "one wire" Mopar alternator, so that one must have an added regulator


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68red440
enthusiast


Reged: Dec 07 2003
Loc: Cincinnati, OH
Re: 100A 3-wire alt, regulator or no regulator? [Re: Yancy Derringer]
      #6561846 - Fri Apr 01 2011 06:07 AM Attachment (33 downloads)

This is a 3-wire. So it sounds like I do need an external regulator. I'll run tests tonight. Any recommendations on a VR for higher amp systems?

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68red440
enthusiast


Reged: Dec 07 2003
Loc: Cincinnati, OH
Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
      #6561848 - Fri Apr 01 2011 06:08 AM Attachment (38 downloads)

Another one

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Yancy Derringer
mopar


Reged: Oct 20 2010
Loc: Montana
Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
      #6562237 - Fri Apr 01 2011 10:12 AM

I can't tell, might be an idea to call 'em. I know that one aftermarket outfit adds a small regulator to "stock appearing" Mopar alternators. It sure looks like regular 'ol Mopar to me.

Regulator? Any good quality regulator should work. Amperage does not matter. I'd buy the "good quality" Echlin (NAPA) or Standard/ Blue Streak.


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jbc426
1970 Cuda Black Series


Reged: Mar 01 2007
Loc: West Coast, USA
Re: 100A 3-wire alt, regulator or no regulator? [Re: Yancy Derringer]
      #6562526 - Fri Apr 01 2011 01:03 PM

...and upgrade that mounting bolt. The one you have on there is likely going to break off at the head in a short time.

--------------------
1970 Plymouth 'Cuda
1968 Plymouth Barracuda Convertible 5.9 Magnum EFI
Here's a little video by Mr Angry about the 1970 'Cuda http://www.youtube.com/watch?v=VzHxZ2f7HwY


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NITROUSN
I Live Here


Reged: Jan 20 2003
Loc: UPPER MICHIGAN, MARQUETTE COUN...
Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
      #6563181 - Fri Apr 01 2011 08:49 PM

Quote:

This is a 3-wire. So it sounds like I do need an external regulator. I'll run tests tonight. Any recommendations on a VR for higher amp systems?




Who hacked the upper pivot like that??? All thread??? I would worry more about the mounting first.


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68red440
enthusiast


Reged: Dec 07 2003
Loc: Cincinnati, OH
Re: 100A 3-wire alt, regulator or no regulator? [Re: NITROUSN]
      #6564605 - Sat Apr 02 2011 04:20 PM

I remounted the alternator with a proper bolt & spacers and hooked up the voltage regulator. The voltage loss through the ground and the hot side was less than .04V for both conditions.

When driving around today I noticed the voltage bounces between 14V - 16V at idle whether the fan is on or off, and it's steady when the fan is on while driving. When driving with the fan off it was sometimes steady and sometimes bouncing.

My 6AL box is mounted on the firewall near the passenger's feet so I can barely hear it buzzing when sitting at idle. When the voltage surges, the buzzing surges with it, but the RPM stays steady at 850 (no vacuum leaks). Similarly when the fan is on at idle, it surges with the voltage.
I'll try a new regulator and see if anything changes.


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