3g set up starting to have problems

[Spook302]

So I have had my 3g install for a month now. The car had great charging untill the other day. the needle used to read about have during idle. now it only reads 12.7-12.8 at idle and when I give it some gas then it goes up into the charging are. This is the problem I had with the stock alt. I upgraded to fix this problem. So why the hell after a month is this problem back with a new 130 amp alt. I am so fustrated.
I used 4 gauge wire. A 150 amp fuse. New block grounds with 4 gauge wire a brand new not rebuilt 95 gt alt from my store. What the hell? I have pulled the alt off and tested on my machine at work along with another new one just to see the read outs and they match. Anyone have this problem. Need help.

 

[jtfairlane]

ditch the stock pulley and get yourself an OD pulley, you will be amazed at the charging difference.

 

[Spook302]

I have an underdrive pulley set. This set did work for about a month. I just started having problems with it.

 

[jtfairlane]

There you go. Like I said, get an alternator OD (Overdrive, not Underdrive) pulley. If you are using the alternator pulley from the underdrive kit, than even with a 3G you are not going to have flawless charging, especially at idle with accessories on. There are numerous companies (and ebay sellers) who have OD pullies for 3G's, and that will speed your 3G's rpms right back up and give you better charging.

The only exception to this is the underdrive pulleys I run, March #1015 . The kit includes an OD alternator pulley that is an even smaller diameter than most OD pulleys, so my charging is perfect.

 

[sawbones25]

Test your battery also. Make sure it doesn't have some dead or dying cells...