alternator help
alternator help heres my problem, cold start my car and volts are right at 3/4 of the way up, starts to warm up and the volts drop down to around 14volts (seems normal to me) but when i stop, or at idle, the volts start to jump around, up down and so on, BUT sometimes the volts dont jump around at all...the alternator i got is a powermaster 150amp alt, car is a 01 trans am....any help would be awesome...and forgot to mention the battery to alt cable is now 2gauge, what others, if any, do or should i upgrade? also would the little wire on top of the alt have any effect on this? wondering if maybe i pulled it a lil loose or something???
maybe a dump question but have you checked all the contact points tomake sure thay are tight and corrosion free? If everything seems good it may be a altenator/regulator. Do you have a altenator tester? I think it can be done with an amp meter too
TECH Fanatic
Joined: Nov 2003
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From: MD
If you broke the exciter wire (wire on top) you'd know the car would not charge at all.
What you're likely seeing is the voltage regulator at work. Most stock alternator voltage regulators are basically dummy gauges that stick around a certain voltage and don't signal unless there is a large varience from the norm. I went through the same thing wondering why the voltage guage would swing so much and found this out. Still charges great and no problem. As long as it doesn't drop below 12 volts or go above 15 I wouldn't worry too much.
What you're likely seeing is the voltage regulator at work. Most stock alternator voltage regulators are basically dummy gauges that stick around a certain voltage and don't signal unless there is a large varience from the norm. I went through the same thing wondering why the voltage guage would swing so much and found this out. Still charges great and no problem. As long as it doesn't drop below 12 volts or go above 15 I wouldn't worry too much.
