I just had a shop put on a stock 85 amp mitsubishi alternator. After they put it on the car died twice while idleing. After I had driven it about 50 miles, the check engine light came on. The car has had a rough time idleing and sometimes dies while idleing. Also, when I first start up the car the voltage is about 12.5V for several minutes (when the alternator isn't on), when it comes on the average voltage is about 15-15.3. It used to stay at about 14.4 until the bass hit, which is when it would drop. What do you think causes these things?
It used to be that the car would run off the battery for about 5 minutes, then the alternator would kick on. Now, just tonight, I was driving all of the way home with my audio system blasting for about 1-2 minutes and the alternator never kicked on. It should have. Its going to the shop that did the work tomorrow.
(Before the new alternator, it would run a 14.4 at idle constantly, the alternator was constantly running)
uhhh, your alternator doesnt "kick on" its constantly running that is the only reason the car runs your car wouldnt run without an alternator, how tight is the belt? try tightening that, try reseting the comp. like they said above, if not then its prebably the alternator, or they did something wrong installing it