Alternator and Volt Regulator not working on FJ40

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Apr 15, 2010
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Recently I noticed that my volts were starting to drop. I figured my alternator was going bad on my 73 FJ40. I have a Chevy SB350 with the Toyota alternator on it. I put a new alternator on and it was still doing it. I decided to replace the voltage regulator. Since they don't make the originals anymore and have been upgraded to solid state I put one of those in. Still, my volts were reading below 12 and kept dropping as I turned on my lights and would drive my rig around. Finally I tried to replace the fuseable wire connected to my starter for giggles and that didn't work. I'm running out of ideas and would like some help if anyone has any other ideas. I just picked up a delcotron with internal voltage regulator and was thinking about hooking that up to see if it would work, since that is the alternator that should go with the 350. I am just having trouble to find a bracket that works. Any help would be appreciated. thanks!
 
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battery?

I hate to say it but have you tried another battery.
Also check out the terminals for condition and look at the cables for any bulges (showing corrosion inside)

I wired in a alt with a built in V/R on my 71FJ I was able to reach with the wires okay.

If you do a search there are a few posts on your alternator I believe and also in the FAQs

There could be other issues like a short but before getting too complicated I would try another battery for sure---After that Google voltage drop checks on charging system or search on this site and you will find step by step troubleshooting instructions---but you'll need a multimeter if you dont have one already
 
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You may want to try starting it up and remove the neg terminal from the battery and connect a test meter between the neg and the positive on the battery, you should be getting well over 12v charging current, increase the idle at the carbie you should see an increase in volts, it will peak and hold no matter how high the revs go, this should establish wether the voltage regulator is working proper, if this is ok then there must be a short or a corroded joint somewhere between your volt meter in the cab and back to the battery. Do you have a large sound system or additional head lights as they may draw a lot of current, therefore a heavier duty alternator may be needed. Let us know how you go. Cheers

good luck.

Nails.
 
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Thanks for the advice. I bought a new batt about a month ago. That didn't work either. Some of the wires have a lot of corrosion on them so i will try to clean them up and looks for some bulges. I bought a delcotron generator that has a built in V/R. I just have to weld up a new bracket to make it work on the FJ. I think it is going to come down to using a multimeter and finding out where I'm lacking continuity.

Nails, i will give this a try tomorrow. I do not have a sound system or extra lighting on it to draw more amps from the alternator. But I ended up buying a 62 Amp Delco which should be more than enough.

I'll keep you guys posted and thanks again for other ideas and advice!!!

Andy
 

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