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#963283 - 03/31/11 06:22 PM 100A 3-wire alt, regulator or no regulator?
68red440 Offline
enthusiast

Registered: 12/07/03
Posts: 323
Loc: Cincinnati, OH
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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#963284 - 03/31/11 06:28 PM Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
Theorio1025 Offline
member

Registered: 07/20/09
Posts: 185
Loc: Staten Island, NY
No if it is internally regulated you have no need for the external regulator

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#963285 - 03/31/11 07:04 PM Re: 100A 3-wire alt, regulator or no regulator? [Re: Theorio1025]
Yancy Derringer Offline
mopar

Registered: 10/20/10
Posts: 606
Loc: Montana
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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#963286 - 03/31/11 07:48 PM Re: 100A 3-wire alt, regulator or no regulator? [Re: Yancy Derringer]
68red440 Offline
enthusiast

Registered: 12/07/03
Posts: 323
Loc: Cincinnati, OH
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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#963287 - 03/31/11 09:48 PM Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
Yancy Derringer Offline
mopar

Registered: 10/20/10
Posts: 606
Loc: Montana
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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#963288 - 04/01/11 06:07 AM Re: 100A 3-wire alt, regulator or no regulator? [Re: Yancy Derringer]
68red440 Offline
enthusiast

Registered: 12/07/03
Posts: 323
Loc: Cincinnati, OH
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?


Attachments
6561846-P1000237(1).JPG (35 downloads)


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#963289 - 04/01/11 06:08 AM Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
68red440 Offline
enthusiast

Registered: 12/07/03
Posts: 323
Loc: Cincinnati, OH
Another one


Attachments
6561848-P1000238(1).JPG (38 downloads)


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#963290 - 04/01/11 10:12 AM Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
Yancy Derringer Offline
mopar

Registered: 10/20/10
Posts: 606
Loc: Montana
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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#963291 - 04/01/11 01:03 PM Re: 100A 3-wire alt, regulator or no regulator? [Re: Yancy Derringer]
jbc426 Offline
top fuel

Registered: 03/01/07
Posts: 2264
Loc: West Coast, USA
...and upgrade that mounting bolt. The one you have on there is likely going to break off at the head in a short time.
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#963292 - 04/01/11 08:49 PM Re: 100A 3-wire alt, regulator or no regulator? [Re: 68red440]
NITROUSN Offline
I Live Here

Registered: 01/20/03
Posts: 15835
Loc: UPPER MICHIGAN, MARQUETTE COUN...
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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#963293 - 04/02/11 04:20 PM Re: 100A 3-wire alt, regulator or no regulator? [Re: NITROUSN]
68red440 Offline
enthusiast

Registered: 12/07/03
Posts: 323
Loc: Cincinnati, OH
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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