Voltage goin nuts!

[Mikedaskter]

I read one of the older posts and it seems familiar but i got some differences. The PO definately hacked some stuff out on this but im trying to work through this. Got a 67 CJ5 3.7 v-6 (buick Dauntless Buick 225 V6 ) My voltage before was spiking (max 16 volts thats topping the voltmeter so maybe higher) So i thought it was a plug that was burnin up and spliced those wires. Now the alternator wasn't putting out anything (took it to autozone) But then on the way home it jumped back to 12 volts but stayed there so maybe it works maybe it dont. so i dont know Shorted wire? Voltage regulator? (dont know where it is) Alternator?
Anyone run into this before?
thanks!

 

[CJ]

What alternator is on it? Does it have the original one or a swapped out internally regulated one?

Sounds like a regulator problem to me... Either a loose wire or a regulator going bad.

 

[Kane]

High voltage equals a bad regulator. Bad wires or anything else will go the other way.

 

[Mikedaskter]

It has had a remanufactured alternator put on it. Whether its a later model alternator or the original kind is beyond me. How would i beable to tell the difference?

 

[CJ]

It has had a remanufactured alternator put on it. Whether its a later model alternator or the original kind is beyond me. How would i beable to tell the difference?

It should have an external voltage regulator - look for some wires coming off of the alternator to a small box bolted to the fender or the firewall.

 

[BajaEdition]

I have to concur with the voltage regulator advice
I am an electrician and know that if the altenator and regulator are 2 different parts this should be the problem, the regulator is what controls the voltage, and the altenator just makes it. If they are one part then the altenator and regulator will need replacement.
In laymans terms lets say the job of the regulator is to make sure the supply voltage is around 14 volts, ( you need that to charge a battery to 12 volts)
I could go into theory but lets just say of working properly your voltage will stay constant and amps will vary.

 

[BrockGrimes]

I had one with a bad ground and it would spaz out, cleaned and fixed the ground
and I had a steady 12v after that.

 

[rushpowersystems]

9 times out of 10 when we see charging system wires hacked it owner will end up installing a 10/12 SI alternator with a one wire regulator, if you have this get rid of it fast - its junk. One wire alternators are for trailer queen show cars only, they shoudl never be used in a driver.

So how many wires are attached to the alternator? Do you have a ground and battery stud on the rear of the alternator with a 2 wire plug in the center that looks like this?

GM 10 DN 100 AMP ALTERNATOR [AD-DN-100] - $129.95 : Rush Power Systems!, High Amp Alternators, Gear Reduction Starters, and other Automotive Electrical Products.

Or does it have a single battery post on the rear with a 2 wire plug on the side at the rear of the alternator like this one?

6-VOLT, 75 AMP NEG GROUND ALTERNATOR [AD-10SI6-75N] - $169.95 : Rush Power Systems!, High Amp Alternators, Gear Reduction Starters, and other Automotive Electrical Products.

If you only have one wire attached to the alternator then you have a one wire alternator. If you have one like the first one described, you have a 10DN alternator and you should keep it unless you have plans on running many lights and/or high wattage stereo. If you have one like the second link you have a 10/12 SI and if it were me I would go back to stock, the 10DN. You could also post a picture of what you have and I can tell you. After we figure out which one you have we can go into testing.

 

[Mikedaskter]

Its not a one wire system its got a plug with 2 coming out (but one is taped up and useless and then it goes to the stud on the back of it) then 2 other wires come off of the stud and go god knows where ive tried to follow them but to no sucess. Ive got it at a friends house now whos a master tech so hes gonna take care of it cheap for me. Thanks for the info maybe next time ill have better luck.