3G Alternator Upgrade no S (White Wire) Terminal / Connection - Vintage Mustang Forums
 
Thread Tools
post #1 of 8 (permalink) Old 07-07-2019, 11:28 PM Thread Starter
Senior Member
 
Join Date: Jul 2011
Location: Richmond, TX
Posts: 1,516
3G Alternator Upgrade no S (White Wire) Terminal / Connection

I spent about 4 hours today getting my butt kicked by what should have been a very simple alternator swap, and no amount of internet searching on this forum and many other sites every yielded an answer, so I thought I would help the next poor sap out by logging what I found.

My 1-wire power master alternator really struggles at low RPMs, probably due to lack of an exciter wire, so I decided to swap it out for a 3G unit. I ordered the unit in April from Amazon, and as usual it set on the shelf for a while before I got around to doing the work. Since the case was the same as my 1-wire, all I had to do was clock the alternator, and modify the wiring a tiny bit to accommodate the ASI wires. The problem came when I got ready to hook up the Stator Wire (white wire) which should route from the S terminal on the 3-pronged plug back to the alternator on a terminal between the ASI plug and the battery stud. The problem, in every search phrase I looked for was:

3G alternator with no terminal for S wire to plug into
3G alternator missing stator terminal
3G alternator missing white wire connection

etc.

You get the idea.

It turns out, that even though the box said I had a part number for a 3G alternator, I had been given a 6G alternator designed to be used with an ECM to regulate the voltage.

Just in case this happens to anyone else.

ajzride is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old 07-08-2019, 05:40 AM
Senior Member
 
j persons's Avatar
 
Join Date: Aug 2010
Location: Natchitoches, LA. at the edge of the swamp
Posts: 3,982
Will Amazon exchange it? After all it's not your fault they sent you the wrong alternator.

John

The Fauxstang. Dynacorn 67 fastback. Dart SHP 363, Close ratio Magnum 6 speed, 3.70 Eaton Truetrac in a fabricated full floater 9", SorT coil over suspension. Still in pieces.
'14 SHO with most all the bells and whistles. Stock for now.
F-150 SCab daily driver
j persons is online now  
post #3 of 8 (permalink) Old 07-08-2019, 08:45 AM Thread Starter
Senior Member
 
Join Date: Jul 2011
Location: Richmond, TX
Posts: 1,516
Quote:
Originally Posted by j persons View Post
Will Amazon exchange it? After all it's not your fault they sent you the wrong alternator.
Pretty sure not, exspecially after I did a little grinding to make the V-Belt pulley work before I realized the wiring was off.

ajzride is offline  
 
post #4 of 8 (permalink) Old 07-08-2019, 10:18 AM
Just some guy
Supporting Member
 
GypsyR's Avatar
 
Join Date: Jun 2001
Location: SC foothills, USA
Posts: 19,062
Garage
A general FYI, the 4G alternators are technically ECM controlled too but they will wire up work the same as a 3G in our cars. I'm not the only one here who is using one. Small nitpicky differences between 3 and 4G's, just a tidbit of info.
GypsyR is online now  
post #5 of 8 (permalink) Old 07-08-2019, 10:24 AM
Senior Member
 
68Hildago's Avatar
 
Join Date: Jan 2015
Location: Edmonton, Alberta, Canada
Posts: 759
Garage
Quote:
Originally Posted by GypsyR View Post
A general FYI, the 4G alternators are technically ECM controlled too but they will wire up work the same as a 3G in our cars. I'm not the only one here who is using one. Small nitpicky differences between 3 and 4G's, just a tidbit of info.
GyspyR is correct (as usual). I am using a 4G from a 2000 Taurus/Sable. But in 2001 the pigtail wiring changed to enable the ECM control, so I just stayed away from those ones when grabbing from the wrecker.
68Hildago is offline  
post #6 of 8 (permalink) Old 07-08-2019, 03:01 PM
Senior Member
 
jdub's Avatar
 
Join Date: Dec 2011
Location: Colorado
Posts: 4,642
Bummer. I've now been burned a number of times by setting stuff on the shelf without looking closely at it first. Annoying.

1965 Mustang
jdub is offline  
post #7 of 8 (permalink) Old 07-08-2019, 03:13 PM
Senior Member
 
wicked93gs's Avatar
 
Join Date: Feb 2009
Location: Nashville TN
Posts: 820
Quote:
Originally Posted by ajzride View Post
I spent about 4 hours today getting my butt kicked by what should have been a very simple alternator swap, and no amount of internet searching on this forum and many other sites every yielded an answer, so I thought I would help the next poor sap out by logging what I found.

My 1-wire power master alternator really struggles at low RPMs, probably due to lack of an exciter wire, so I decided to swap it out for a 3G unit. I ordered the unit in April from Amazon, and as usual it set on the shelf for a while before I got around to doing the work. Since the case was the same as my 1-wire, all I had to do was clock the alternator, and modify the wiring a tiny bit to accommodate the ASI wires. The problem came when I got ready to hook up the Stator Wire (white wire) which should route from the S terminal on the 3-pronged plug back to the alternator on a terminal between the ASI plug and the battery stud. The problem, in every search phrase I looked for was:

3G alternator with no terminal for S wire to plug into
3G alternator missing stator terminal
3G alternator missing white wire connection

etc.

You get the idea.

It turns out, that even though the box said I had a part number for a 3G alternator, I had been given a 6G alternator designed to be used with an ECM to regulate the voltage.

Just in case this happens to anyone else.
Not that you want to do this modification...but any alternator meant to be regulated by an ECM can be regulated by an external regulator as well...my choice of regulator when I do this is from an 80s Dodge Omni(probably because I have a few sitting around and the wiring is so simple, I am sure other external regulators will work just fine though)
wicked93gs is online now  
post #8 of 8 (permalink) Old 07-08-2019, 09:51 PM Thread Starter
Senior Member
 
Join Date: Jul 2011
Location: Richmond, TX
Posts: 1,516
Quote:
Originally Posted by wicked93gs View Post
Not that you want to do this modification...but any alternator meant to be regulated by an ECM can be regulated by an external regulator as well...my choice of regulator when I do this is from an 80s Dodge Omni(probably because I have a few sitting around and the wiring is so simple, I am sure other external regulators will work just fine though)
Iíve gone through great lengths to clean up my wiring. Definitely not interested in adding back a regulator. Thanks for the advice though.

ajzride is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome