3g swap issues.
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3g swap issues.
Alright guys, I'm having trouble on my 3g alternator swap.
I'm on alternator #3 (and its not working) since it I did the swap. Can't figure out what's going wrong.
The alternators work for a little while (a few minutes) then stop.
The second one was putting out 14.2 volts, I drove above 20 miles, jumped someones vehicle and at that point it wasnt working anymore.
This last one was putting out 13.5 volts, I turned the truck off, and then back on, and it's not working.
The ignition lead is drawing current (used my test light). I used the Gr/R wire from the harness.
Fuse isn't blown, and grounding is good. I'm stumped.
Could I be getting multiple bad alternators? What else could be causing this?
I'm on alternator #3 (and its not working) since it I did the swap. Can't figure out what's going wrong.
The alternators work for a little while (a few minutes) then stop.
The second one was putting out 14.2 volts, I drove above 20 miles, jumped someones vehicle and at that point it wasnt working anymore.
This last one was putting out 13.5 volts, I turned the truck off, and then back on, and it's not working.
The ignition lead is drawing current (used my test light). I used the Gr/R wire from the harness.
Fuse isn't blown, and grounding is good. I'm stumped.
Could I be getting multiple bad alternators? What else could be causing this?
Senior User
Joined: Feb 2014
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So you didn't add the 560ohm resistor? From what I understand this is the wire that excites the alternator. When I first did mine I was having problems because my amp gauge in the cluster was bad, it would work when it wanted to, so I put in the resistor to an acc wire. Since then it has been fine. Also when I first did mine I was getting junk yard alternators I think I went through 3 done would put out 20v down to nothing. So I went and bought one for a 95 ford wind star it was like just over $100 is been flawless since.
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From: Spencer Mountain, NC
Think you need to review the wiring diagram for the 3G swap. If I remember correctly the 3G does NOT work with the factory amp gauge. I had my amp gauge converted to a volt meter when I did my 3G swap. There is NO resistor in my system.
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I didnt know because none of the diagrams list watts, so i went with a 1w. But I'm sure you could use a 1/4 I don't think it is pulling much power, but a incandescent light bulb works too. It only lights the bulb if the alt goes out, but it uses the power flowing against it to excite the alt.
I just ran mine to the starter solenoid, the small one that is hot when the key is turned on not the starter signal wire the one towards the radiator
I just ran mine to the starter solenoid, the small one that is hot when the key is turned on not the starter signal wire the one towards the radiator
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Joined: Apr 2006
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From: mid-MO
Read page 51 of the thread entitled "just did a 3G upgrade". Sorry can't supply a link on my phone. I had a very similar question and Redroad was very helpful in solving that, but I think you will find it may answer your question. If the alternators are up and dying (mine did that too) I would suggest checking the brushes that ride on the shaft located under the volt regulator on the back of the alternator. Mine were toast, so I replaced them for like $20. Works like new now.
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Wiring is all good with exception of a resistor possibly needed. On this last one I changed the regulator and brushes, it worked for a minute until truck got turned off. Once the truck turned back on, I was only getting 12.3 volts.
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Elder User
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From: like subarctic, brrr man!
This one is a stumper...
Re-check wiring, even shaking and wiggling it. Check battery? Maybe check voltage on that green/red wire? Check your Grounds, like between firewall and block, and battery to block? I like adding a couple more from block to frame to body.
Red/Green wire, you have the idiot light light cluster? or the crazy confusing wiring gauge cluster?
The resistor is used for a just in case the idiot light burns out so you don't lose the alternator function.
FYI, I jump with mine all the time and never had issues with it, except that one time I reversed the polarity ... doh
Re-check wiring, even shaking and wiggling it. Check battery? Maybe check voltage on that green/red wire? Check your Grounds, like between firewall and block, and battery to block? I like adding a couple more from block to frame to body.
Red/Green wire, you have the idiot light light cluster? or the crazy confusing wiring gauge cluster?
The resistor is used for a just in case the idiot light burns out so you don't lose the alternator function.
FYI, I jump with mine all the time and never had issues with it, except that one time I reversed the polarity ... doh
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Tuned
Joined: Jul 2001
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3G with OEM amp gauge
I read in this series of posts that the 3g conversion will not work if you have a factory amp gauge--is that correct? I do not want to convert the amp gauge to a voltmeter. Hope someone can clear this up for me.
Thanks
Thanks
Senior User
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No it works just fine, you just have to wire in the 560 ohm resistor to a wire that is hot when the key is on. It would be pretty simple if you just planned it from the start and did it.
I'm not sure if the amp meter will excite the alternator by its self but I would think it would because it does on the stock alt. I just don't use the amp meter any more, I would like at some point to add the dummy light to mine. But i just got one of those lcd volt meters with usb charging that goes in the cigarette lighter, is pretty slick.
I'm not sure if the amp meter will excite the alternator by its self but I would think it would because it does on the stock alt. I just don't use the amp meter any more, I would like at some point to add the dummy light to mine. But i just got one of those lcd volt meters with usb charging that goes in the cigarette lighter, is pretty slick.
Tuned
Joined: Jul 2001
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Thanks Jay Blu; can I use the wire that feeds the electric choke on my carb? It's hot only when the ignition is on. I don't know if it is interrupted when you move the ignition key to the start position or not, or if that would be an issue.
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Yeah that should be just fine as long as its not the coil pos wire, which is not a full 12v. Some people try to run their choke off of the pos of the coil and that would probably put extra strain on the resistor wire for the ignition. The stock coil wire measures at 6v, so if you have 12v I would say you are fine.
I wouldn't see any problem with it cutting out under starting, all it would do is not charge for the 30sec that you were cranking it over.
I wouldn't see any problem with it cutting out under starting, all it would do is not charge for the 30sec that you were cranking it over.
Elder User
Joined: Sep 2014
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From: like subarctic, brrr man!
The Alternator has a stator output for elecric choke, like the original oem does. The white wire that jumps from the stator to voltage regulator on the 3g alt. Only use this for the stock electric choke, and not the aftermarket chokes. Aftermarket usually requires a full 12volts.
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Well, I feel stupid. I fixed the issue. It was a worn belt. I had it stretched super tight, still guess it was slipping. I just found it kind of weird because it didn't squeal at all. Put the new belt on, tightened it and voila, 14.5 volts. Feel kind of silly now however.
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