Charging issues

[4mk3-4life]

I replaced the alternator and battery because the stock alternator had stopped working and now all of a sudden it doesnt charge all of the time. Some times you can be driving the car and it runs fine but then the lights start to dim and the battery light comes on and some times it stays on for a while and the car dies but most of the time it goes away but the lights on the dash are still a little dimmer than normal... Any help on what it could be?

 

[87tomanymods]

check for loose or corroded terminals and conections. also just cause the alt is new dont mean its good ive seen plenty not work right out of the box. and once you deep cycle a bat its never the same

 

[4mk3-4life]

i replaced the wire the runs from the battery to the alternator because it was corroded at the battery thinking the could be the problem, but now it doesnt seem to be charging at all, and i checked for power at the alternator and its there. I'm going to order a new alternator tomorrow but i'm thinking its something else now i just dont know what.

 

[87tomanymods]

try checking all the fuses and .also did you check for power (to the alt) & from the alt remember it takes 12v to make 14 .

 

[4mk3-4life]

all fuses look good, and yes i did check the power to the alternator, but the battery was right dead so i have it on the charge now to see if it makes any difference.

 

[4mk3-4life]

ok so i took the alternator off and but it on a friends car and it worked fine. so i went back and looked at the wiring and one wire the goes to the plug was hardly hanging on so i fixed that wire, and now it reads a steady 12v with the car running but it doesnt seem to charge the battery, doesnt seem to drain it either. I havent really taken the car for that long of a drive cuz i'm scared just in case it doesnt work but it seems do be fine just wont charge.

 

[87tomanymods]

whats the voltage w/out engine running .the alt is only suposed to put out like 2v more than bat voltage .so if the bat is at 10v and charges at 12v its doing its job . also for a load test the voltage while cranking shouldnt drop below 10v. also how many amps is the alt putting out. and remember even a brand new bat that has been drained once will never be the same make shure it has enough cranking amps. hope this helps good luck

 

[4mk3-4life]

the battery reads 12v and while the car is off and the alternator reads 12v when the car is running.

 

[87tomanymods]

try the trouble shooting section in this http://www.scribd.com/doc/2887024/12-CH

 

[loki2043]

shouldn't the alternator be charging at 14v?

 

[4mk3-4life]

ya thats the problem, i got it tested and they said it worked fine but when you put it on the car it doesnt so i think it has something to do with the wiring.

 

[loki2043]

is the voltage regulator internal on our alternators?

 

[87tomanymods]

give or take a few tenths of a volt yes

 

[4mk3-4life]

i had bought a new one cuz the stock one crapped out and it has a internal regulator, but i have to say the wires that go to the plug on the alternator arnt in the best of shape so i'm going to buy a new wiring harness and see if that fixes it.

 

[87tomanymods]

yes give or take a few tenth of a volt

 

[4mk3-4life]

so i hacked the wiring together untill my new wiring harness gets here and took the car for a decent drive and everything seems to be working ok. Thanks for all your help, i'll update if it doesnt work out.