13 V when running is the low side of good but almost bad. What 69 is saying is that if you short the regulator, the alternator then can produce its maximum amount of voltage. This should be in the area of 15-25V DC If it does when you short the regulator but will not produce over 12V normally the regulator is bad. If you short the regulator and nothing happens then other things are bad like the comm, field coils, sator, diodes or brushes.

Massey

 

Did grounding out the regulator make no difference? The voltage regulator basically acts like a switch, telling the alternator when to put out depending on the need of the battery. If grounding it out made no change in output, that would mean the alternator has something else wrong with it internally (bad rotor, stator, diode). At 13 volts, you're barely getting 12 volts by the time it makes it to the battery.

 

Im reviving this thread because i never solved the problem. So if this test makes the alt kick more its the voltage regulator GOT IT! thanx. any idea how to replace the voltage regulator? I do have a spare alt with a bad diode for parts.

 

I also wanted to add that when i inspected my alt it had a smaller pulley than the stock alt. Would this be why its trowing less voltage?

 

Smaller pulley on the alternator means it spins faster than stock. It will required more HP and should output more watts. The voltage should be higher than stock.

 

So I just replaced the voltage regulator with a used one and now I'm getting 18v so apparently the voltage regulator was bad. I'm going to buy a new and see how it goes.

 

Regulators for our cars can not be found at Autozone ar Advance. We have CS 130 alternators. You will have to source them here
High Output Alternator, 200-250-300-350 Amp Alternators, high output alternators, GM,Ford, Chrysler Dodge Alternators
They start at $28
National Quick Start Sales, High output alternator, Alternator & Starter Parts - Voltage Regulator

 

I got one at lehr automotive. First time going there and they carry everything to rebuild alts and starters. It cost me only $30 but I broke a prong so tommorow at work I'm going to solder back together and il let you know how it goes for futures reference. Parts number was d705. Il probably start a new thread with pics and tutorial.