Just cannot get excited

[Broncmeister]

haha OK the title may be a tad misleading but honestly it is exactly on topic. I have the Motomaster 1 wire alternator and I just cannot get things to charge.

Brand new battery, brand new alternator (130 amp). Both are a matter of days old, both have been returned and checked and both have been given a perfect bill of health. Here's the problem, for some reason the charging system refuses to work once it's all back together. I have 12 volts before starting, and after the truck is started, yup... 12 volts. It's like the alternator isn't getting excited and beginning to charge. Belts are good and tight, and no slippage that I can detect. I hook cables up to my sons jeep and voila, 14.5 volts. but as a stand alone this thing just refuses to charge or I assume refuses to excite.

What the heck can be causing my problem?

 

[jckkys]

It's likely the integral voltage regulator. Is it just screwed on like the ones on 3Gs? I carry a spare for the 3Gs on my 4.6s. They only cost me $16 at the alternator shop.

 

[Broncobowsher]

Since you are talking a non-stock 130A alternator, you need to tell us what alternator you are working with. From your lack of description I can only guess you have it wired wrong. How wrong will depend on which one it is and what wires you hooked up to it.

 

[broncnaz]

If its a one wire then Id say it shouldnt be hooked up wrong. How are you checking the voltage? does the bronco have a voltmeter or are you using a hand held one? If your using one that you installed in the bronco then maybe your issue is with it or its wiring. Since your showing 14.5 on the jeep.

 

[DirtDonk]

Is there a link to any web information on the Motomaster stuff? A quick search didn't give any results other than this thread.

Do you know if it's based on a Ford alternator, or GM design?
Any other info you can provide, and/or pics?

Probably something simple. Hopefully anyway.
What wire are you connecting to it's main output connector? Did you verify that there is full battery voltage to that wire before connecting it? If it's the original Bronco Black w/yellow charge wire, maybe something's gone wrong with it between the alternator and battery or firewall.

And lastly, is this for the '73 or the '68?

Good luck.

Paul

 

[ntsqd]

Seems like One-Wire alt's just aren't worth the trouble. A second wire isn't all that hard to run.

I'd call the vendor of the alt and ask them what they want to do.

 

[Broncobowsher]

The parts store tested it OK, so it works. There is an installation error.
So again, not knowing what parts you are working with, can't help.

Can't be too hard since the parts store figured out how to put it on the tester.

 

[Broncmeister]

Since you are talking a non-stock 130A alternator, you need to tell us what alternator you are working with. From your lack of description I can only guess you have it wired wrong. How wrong will depend on which one it is and what wires you hooked up to it.

it's a motomaster 1 wire 130 amp as I stated in the OP, I'm not sure what more I can give unless there are some sort of serial numbers I can give you off the back of it or something?

 

[Broncmeister]

If its a one wire then Id say it shouldnt be hooked up wrong. How are you checking the voltage? does the bronco have a voltmeter or are you using a hand held one? If your using one that you installed in the bronco then maybe your issue is with it or its wiring. Since your showing 14.5 on the jeep.

Yes I have a voltmeter in the bronco, plus I have a multimeter that I've checked it with, plus I have taken the bronco into a service station to have it tested on the truck with their equipment. It just isn't charging

 

[Broncmeister]

Is there a link to any web information on the Motomaster stuff? A quick search didn't give any results other than this thread.

Do you know if it's based on a Ford alternator, or GM design?
Any other info you can provide, and/or pics?

Probably something simple. Hopefully anyway.
What wire are you connecting to it's main output connector? Did you verify that there is full battery voltage to that wire before connecting it? If it's the original Bronco Black w/yellow charge wire, maybe something's gone wrong with it between the alternator and battery or firewall.

And lastly, is this for the '73 or the '68?

Good luck.

Paul

There is only one wire to connect, so that is the one I am connecting to my charging system. I have taken the alt out and brought it back to where I bought it and they bench tested it from the wire without removing it, and it gave 14.5 volts. When it is reinstalled in the vehicle, no charge, it doesn't excite. This is a 1 wire alt, nothing to really go wrong with the firewall, it's only wire connects directly to the battery and that's it. BTW this is my second 1 wire alternator, the first one served well for 10 years, so I know that there is nothing wrong with how it is wired. Oh and it's for the 73.

 

[Broncmeister]

The parts store tested it OK, so it works. There is an installation error.
So again, not knowing what parts you are working with, can't help.

Can't be too hard since the parts store figured out how to put it on the tester.

yes, but the question is why is it not exciting. Is it not getting enough RPM to excite? Is there something wrong with the internal magnet? Is it possible the new battery has problems with not allowing charging? Don't be so quick to leap at installation error when there can be other issues at play. This is the second alternator of the same type, and the first one served well for 10 years, installed identically. The installation is not what is wrong here.

 

[Broncmeister]

edit to add. Apologies to everybody on the manufacturer. I deal so much with Canadian TIre that I automatically called it a Motomaster alternator. It is not. It is the Ford Motorcraft alternator.

Genuine ford parts

 

[Broncmeister]

Another follow up. took it back again and they gave it another benchtest. 14.5 volts. If anybody is familiar with the wiring of the 1 wire Motorcraft 3G alternator, could you help me out here? I have replaced my vehicles ground cable. I have the A pin on the regulator plug going to the battery output stud, and the S pin on the regulator plug going to the stator stud. I have a 4 gauge cable running from the battery output stud going up to the battery. I am positive I have it wired correctly but if not I am certainly open to enlightenment.

 

[Broncobowsher]

What do you have the "I" wire hooked to?
That needs to be switched with the ignition. Without that the alternator doesn't know when to turn on.

I have ran into this many times before. Someone gets a new modern alternator and thinks it is just one wire. It isn't. It has an output wire (the big one) and "one wire" needed to turn it on, the second wire.

Quick google search, http://www.fordtruckclub.net/forum/showthread.php?t=6803 second diagram down.

 

[Broncmeister]

What do you have the "I" wire hooked to?
That needs to be switched with the ignition. Without that the alternator doesn't know when to turn on.

I have ran into this many times before. Someone gets a new modern alternator and thinks it is just one wire. It isn't. It has an output wire (the big one) and "one wire" needed to turn it on, the second wire.

Quick google search, http://www.fordtruckclub.net/forum/showthread.php?t=6803 second diagram down.

Yes that is true of the 3G alternator, however this alternator in question is the 3G 1 wire alternator, exactly like the ones you can get at BC Broncos. Here is their wiring diagram. Note the I wire is left blank and does not go to ignition or anywhere for that matter:
http://www.bcbroncos.com/3g1wire with water mark.pdf

 

[broncnaz]

All sounds good maybe the case is not grounding properly.

 

[DirtDonk]

You do know that Ford does not make a 3G "1-wire" alt, correct? The 1-wire versions are aftermarket only as far as I know. We sell one, but it uses a non-stock voltage regulator.
Could it be possible that your new one is a standard 3G? If so, that would explain why your old one worked as-wired, but the new one does not.
Or did you purchase it specifically from a vendor (Canadian Tire?) that says it's sold as a custom 1-wire version of a multi-wire 3G?

It sounds like you were watching them test it, so I suppose that would have been cleared up as you were watching and they didn't connect anything different than what you already had. I know you said they used the same wire, by which I assume you mean the 4ga wire you're using on the truck, but I wanted to be clear. 'Cause I'm with you, that there is no "normal" reason that it would work on the stand and not on your rig. Other than what broncnaz said about grounding.

Here again though, you said you replaced the ground cable. But where does it attach to the engine? And did you by any chance paint the engine and brackets (and maybe even the bolts) where the alt mounts? The bolt threads are sometimes enough, but if a lot of new paint is present, that could be enough to interrupt the flow.

Hang in there. It's gotta work soon!

Paul

 

[DirtDonk]

You also said you hooked cables up to your son's Jeep and got higher readings. Was that just using jumper cables to his battery? Or were you doing something else?

Sorry to go all the way back to your first post after all this, but I figured I might as well try to work from another angle for the moment.

Paul

 

[Broncmeister]

Thanks everybody for your help! The info in this thread pointed me in the right direction! Here is what happened. When i bought the new alt the parts guys assured me it was a 1 wire alternator. After exhausting all options and reading replies in this thread I decided it could not be the case. I ran an exciter wire to the ignition from the I terminal and boom, 14.5 volts. So i am back up and running and charging woohoo! Next question, is my wiring correct? My wiring is as follows: A is to battery ouput stud, S is to the stator stud, and I is going into the cab onto the center post of the ignition switch (I believe it is called run or start)

 

[DirtDonk]

Not sure about all of them, but the new exciter wire should be in RUN only at some point.
Not that it won't work the way you have it, but any time you're sitting there with the key in ACC listening to the radio or whatever, your alternator is juicing up too.

I don't think it will automatically hurt the alternator, and may only use a tiny bit of extra battery juice, but one of the others with more knowledge in that department can say for sure.
But Ford used a position that was hot in RUN only. You should be able to see it right there on the back/side of the ignition switch in fact. It might even still run out to the right side of the engine compartment where the old voltage regulator was/is.

Paul