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No spark. (UPDATE: figured it out)

ObscureMachine

Seatbelt Orifice Officer
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This is the alternator on my rig;

A. Is this a stock alternator?
B. What's up with the wiring (see below)?
C. What do I look for at a parts store to upgrade to 3g. I've seen some Taurus alts, but there mounting holes are all screwy


6960573024_924fb8f36a.jpg


This is where the wires connect to the alt. One of the wires is disconnected / broken and frayed. Just sitting there. RED ARROW

7106663237_7c36115053_b.jpg


These wires just run into the wiring harness;

7106644127_0da824bc8d_b.jpg
 
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dlong

Jr. Member
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Feb 28, 2011
Messages
57
Loc.
Las Vegas
Looks like a stock alternator to me as far as the wires I'm not sure. There are several donor alternaors that work do a 3g search. I ended up using a 95 ford taurus 3.8 liter and it bolted up with no issues.
 

broncodriver99

Bronco Guru
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Jan 27, 2008
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4,780
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Glen Allen, VA
Yep. Stock alternator. Should be 3-4 wires. Power out, field, ground, and some years a stator wire for the electric choke.

Here are some good wiring diagrams: http://seabiscuit68.tripod.com/

Also, that rubber block is just formed to the wires. They go all the way through it except for the ground wire which terminates on the lug that sticks out of the side of the rubber block and is bolted to the gnd terminal of the alternator. If you are careful with a razor blade, you can cut it off and repair the freyed wiring.
 
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ObscureMachine

ObscureMachine

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ObscureMachine

ObscureMachine

Seatbelt Orifice Officer
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Alternator is dead. I've decided to buy one from RJM (I think). Will the pulley on my stock alternator work on the 3g? If not, does typical parts place have them, and is there a best size to get?

thanks!
 

tw322

Sr. Member
Joined
Dec 23, 2011
Messages
459
I am right in the middle of doing this now. I got mine (95 Taurus 3.8 130 amp 3g) brand new from alternator pros in AZ for $123.99 and free shipping(based on a recommendation from Motoman on here). I know enough to get myself into trouble so I posted this thread which really helped me understand...especially the BC Bronco wiring diagram. (courtesy of 70_Steve).
http://classicbroncos.com/forums/showthread.php?t=205140

Hope that helps...good luck.
 
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tw322

Sr. Member
Joined
Dec 23, 2011
Messages
459
They advised that the 3g alternator is internally regulated and to dump the VR completely.
 

70_Steve

Old Guy
Joined
Dec 13, 2002
Messages
8,317
Sorry, just read this thread this morning.

Yes, the stock pulley will swap over. But you might experience some belt squeal on startup. The stock pulley doesn't have quite enough surface area for the belt to drive the alternator when it's putting out anywhere close to full current, as it might on startup.

The 3G is internally regulated so yes, you can dump the stock voltage regulator. If you're following the wiring diagram on BCBronco's or RJMs site, the alternator will require a Hot-In-Run connection. That will be the Green w/Red Stripe wire (904), currently wired to the stock voltage regulator.

The other question should be "What do I do with that big-a$$ black w/yellow stripe wire (37) currently connected to my stock alternator?" That wire is one end of a loop that starts at the alternator, goes into the cabin behind the dash, through the ammeter, has several splices/connections to power the entire Bronco, the goes back out as a black wire (38) to a fuseable link at the BAT+ side of the starter solenoid. Couple possible things to do.

1. Cap off the wire and forget about it.

2. Connect the Black w/Yellow stripe (37) to the Black (38) wire at the fuseable link.

My Bronco had the fuseable link replaced with a circuit breaker. So one end of the circuit breaker is connected to the BAT+ side of the solenoid and the other is connected to the big Black wire (38). I tied the black w/yellow wire (37) to the circuit breaker along with the Black (38) wire, so I now have both ends of the loop able to supply power to the Bronco.

Also, one last note, if you haven't seen this in othe 3G threads. You ammeter will no longer function. You will need to add a Voltmeter somewhere to monitor the state of the charging system. The good news in that is you can get much more information from the voltmeter than you could from the ammeter.
 
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ObscureMachine

ObscureMachine

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Thanks Steve. I didn't know about those wires. So, since my fusible link is still there on the black wire, I'll probably just tie 37 and 38 together.

I will also probably get the gauges refurbished at some point and have the voltmeter added.
 

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70_Steve

Old Guy
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I will also probably get the gauges refurbished at some point and have the voltmeter added.
I wouldn't delay adding a voltmeter. The charging system is way too important to not monitor, even for a little while. I picked up a cheap voltmeter in a "bargin bin" at my local Autozone for $10 to get me by until I had a chance to do a more permenant installation. That was 5 years ago, and I'm still using the same voltmeter.
 
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ObscureMachine

ObscureMachine

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I wouldn't delay adding a voltmeter. The charging system is way too important to not monitor, even for a little while. I picked up a cheap voltmeter in a "bargin bin" at my local Autozone for $10 to get me by until I had a chance to do a more permenant installation. That was 5 years ago, and I'm still using the same voltmeter.

I'll take that advice. Did you connect to the ammeter wires?
 
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ObscureMachine

ObscureMachine

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Viper, I'm so not good at wiring. I wish I had your knowledge and understanding. It's like Tryg, I could never get my head around it. (BTW- my wife an I own an electrical contracting company!!!:eek: - we inherited it)

Any way. do I just run a hot wire and a ground wire to the voltmeter? Is there a specific place to connect the hot wire. sorry if that's a stupid question.
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
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Any way. do I just run a hot wire and a ground wire to the voltmeter? Is there a specific place to connect the hot wire. sorry if that's a stupid question.

Yep. Connect the hot wire to the stud terminal of the ign sw so the voltmeter is only on when the key is on or in acc.
 
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