3G Alternator Install Tech

[Guest]

[Joel5.0]

In 1996 Ford publicly recognized the fire hazard caused by the 2G alternator and released TSB 96214. This alternator design caused increased resistance and heat which could damage the wire harness and alternator. A small percentage of vehicles actually caught on fire!

Fords 3G alternator was a giant leap in technology and quality. The 3G was internally regulated, used two internal cooling fans, sealed bearings, and had a superior battery stud. The 3G’s were more efficient, and produced more amperage at idle than any of its predecessors.

Early 1985-93 serpentine brackets can swap to the 95amp 7.0″ pivot 3G without any work. The larger 130-200amp will require a small area clearanced with a grinder.

The 3G typically bolts right into the stock brackets used on older V-Belt mounts without any work. Use the 7″ pivot for best results, the 8.25″ pivot can be used if there is room.

The larger 130-200amp side mount 3G will bolt into newer serpentine brackets without any changes. The stock harness can be used with a larger battery charge cable.

Plug in the Harness, bolt on the Charge Cable, then push the Protective boot into place:

You need to connect the single wire left on the harness to a wire that is HOT with the key in RUN. Ford has used a Green/Red wire on their vehicles for over 50 years. So it’s simple to find that wire that went to the old alternator and use it now.

The last thing you need to do is connect the 2Ga battery charge cable and mount the Mega-Fuse. The Battery charge cable should be bolted directly to the batteries positive post, or you can follow the positive battery cable to the starter solenoid and bolt it there.

If you purchase a 3G alternator from other sources it typically won’t have threads.
You will need to use a longer 3/8″ bolt and nut.

Or drill out the mount hole and install a Heli-Coil.

[juiced coupe]

IMO, the alternator stud isn't the best location for the yellow/white wire.

It would be better to have it connected wherever power is routed from. Starter solenoid,  remote power point, fuse box, wherever. That will ensure that everything has proper voltage available.

[Joel5.0]

IMO, the alternator stud isn't the best location for the yellow/white wire.

It would be better to have it connected wherever power is routed from. Starter solenoid,  remote power point, fuse box, wherever. That will ensure that everything has proper voltage available.

Agree..... it should be placed past the mega-fuse with a 20A inline fuse.

[scienceguy]

I scavenged a 130A 3G alternator from the local boneyard years ago to install on the mustang.  Made my own wiring harness by modifying the stock pigtail that came with the unit.  What I found from my first hand experiences...

1.  Bolted right in place!  Zero modifications required to physically mount it.  Used the single pulley.  Barely a thumbnail of clearance, but no clearancing required for the pulley.  (some clearancing could be required on single pulleys)

2.  Bottom threads for tightening/tensioning are METRIC.  You will need to keep this bolt from the donor car, or be ready to buy a new one.  Old SAE one will NOT work.

3.  Unit has AMAZING low rpm charging capacity!  I use a tiny crank pulley, have electric water pump, fan, fuel pumps, etc...  and the thing charges just fine...  EVEN AT IDLE!  Have never had an alternator that does such a good job at low rpm!!!

4.  Have highly recommended this alternator to anyone who would listen.  MAJOR upgrade for any old car.

Thanks for the details!
 

[Joel5.0]

2G Alternator Wiring Diagram

3G Alternator Wiring Diagram Alternative

3G Alternator Wiring Diagram Recommended

[CDW6212R]

The 3G unit comes in the widest range of applications, housing dimensions etc. They have the best aftermarket support for parts and upgrades, versus other Ford units. I learned that recently from my local repair shop. They would even take spare 3G units for trade value, which is interesting.


I'm going to be using 4G's on my four projects, simply because the front dress(Explorer brackets) I want takes them. The 4G is stronger in some ways, but with almost no aftermarket support, and the main stator assembly is prone to fail(big cost compared to a whole alternator). So they say the 4G should be checked and rebuilt at sooner intervals than other units.

[juiced coupe]

Here is the basic wiring layout for my car. The primary wiring has been in place for years without any issues. The relay box, progressive, and MSD wiring are all new.

[Joel5.0]

Here is the basic wiring layout for my car. The primary wiring has been in place for years without any issues. The relay box, progressive, and MSD wiring are all new.

I know what you are trying to establish but.... it is not correct + BTSTDTRT a few times.

Placing the "sensing" or demand input downstream, or bypassing other circuits, is not the way it works. The demand or input the armature (A) needs to include all the circuits previous to the power distribution deal, reason why it is connected close to the alternator output wire.

On a race only setup as yours, fine. BTW,  your setup bypasses the MSD demand on the alternator. Now, keep in mind the number of circuits and grounds in a driver or S&S setup, if you connect the "A" alternator wire to the headlights (as an example), the alternator will undercharge the battery due to the low current demand during the day.

Again, the "A" wire needs to be able to "see" all the circuits in the car, reason why it is connected past the alternator mega-fuse, before the power distribution connectors, to monitor the demand from the car circuits as a whole....... not a specific or selected ones. 

[juiced coupe]

I know there are a few theories on this one. I used the one recommend by Mad Electronics.

His reasoning is that by placing the voltage sensing wire at the junction point, that it will supply its rated voltage at that location. If there is 14.5 volts at the junction point, it will only be higher at any point before that.

The wiring for the relay box and fuel pump were more for convenience, but the above reasoning still applies.

The wiring for the MSD is intentional. Its actually the recommended routing by MSD. The battery and capacitor smooth out the alternators output before reaching the ignition box. It was previously wired to the junction point and grounded to the frame at the same point as the engine,  it failed twice.

But at any rate. When I get my wiring completed,  I'll happily try it both ways and report my findings. Seeing that my car has 30+ feet of wiring between those two points, it should put either theory to the test.

[Joel5.0]

I know there are a few theories on this one. I used the one recommend by Mad Electronics.

His reasoning is that by placing the voltage sensing wire at the junction point, that it will supply its rated voltage at that location. If there is 14.5 volts at the junction point, it will only be higher at any point before that.

The wiring for the relay box and fuel pump were more for convenience, but the above reasoning still applies.

The wiring for the MSD is intentional. Its actually the recommended routing by MSD. The battery and capacitor smooth out the alternators output before reaching the ignition box. It was previously wired to the junction point and grounded to the frame at the same point as the engine,  it failed twice.

But at any rate. When I get my wiring completed,  I'll happily try it both ways and report my findings. Seeing that my car has 30+ feet of wiring between those two points, it should put either theory to the test.

I think that we are saying the same thing. The point is to have the demand request "input" or "A"wire at the main power distribution point or junction. I changed the "Recommended" diagram to make it clear. 

[juiced coupe]

I think that we are saying the same thing. The point is to have the demand request "input" or "A"wire at the main power distribution point or junction. I changed the "Recommended" diagram to make it clear. 

Yea, my POS diagram isn't the best either. The voltage sensing wire ties in at the main junction point on my car. It is located where the factory starter solenoid was. Looking back, I can see how that could be mistaken for the fuse box or similar point.

[rob342]

is there any reason not to connect it like i have it here on the right?

i'm unexpectedly doing this TODAY since my alternator took a dump.

[Joel5.0]

"NOT" to connect it like that? Not really an issue or problem, aside the fact it will make the system less "responsive" to load changes......

[rob342]

i will do it the way it is recommended. i want it perfect.

[rob342]

just to verify, the wht/blk wire, center of the 3 pin connector, gets cut and looped over to the spade terminal. leaving the remainder of the wht/blk wire to be discarded?

---nevermind. i see it's just a loop. i trimmed the unused connector to fit the new alternator