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Discussion Starter #1
I recently converted my 65 nova to a 10 si alternator and have been having problems that I am at a loss to explain. I Ran a 10 ga. wire to the pos. battery terminal, the sensing wire to the horn relay. I hooked the field terminal to switched 12 volts. I noticed that the alt. was overcharging so I think, bad reg. and replace the alt with a new one. Much to my dismay I find out that the new one is doing the same thing. It will sit there idling at 14.5 and then all of the sudden it will max out at 16-17 volts and start to boil the battery intermintently. On and off like there is a loose connection but unfortunately I have checked everything to no avail. The only thing that is questionable to me is the #1 field wire hook up which from my understanding doesnt do anything in my application anyway. The other thing is when I installed the alt. I used a cheap parts store pigtail which was shorting out the sensing wire against the case in both cases. I took the old one in to be tested and they said it was good?! I am wondering if alternators fail intermintently or not.
 

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I'd guess a problem in the sense wire. Make sure it has a bullet-proof connection to battery voltage. If the voltage on it drops or goes away, the alternator will try and compensate by going to maximum output until the sense circuit shows normal voltage.
Alternators usually don't fail intermittantly but connections sure do.
 

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I figured out the problem. The cheap auto parts pigtail connector had a really loose fit allowing the plastic to melt on the back of the connector. This in turn allowed the sensing wire to ground out against the alt case. It damaged the regulator.\
Replaced the regulator and it worked great! Sometimes the most obvious things arent so obvious.
 
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