i have a 1989 civic with a b18a1 swapped in it and my alternator is not charging my battery. i thought i just needed a new one so i went and got one and put it in and it still wont charge the alternator is only putting out 11.9 volts and the alternator is brand new and i bench tested it before i put it in and it was working perfect. if someone can help me figure out what is going on that would be amazing i have searched all over the internet and i could find nothing but thanks in advance if someone helps

 

is the alternator wire connected at the main fuse box?

 

yeah the whire is connected i am getting like 11.7 at the battery when the car is on but all the wires are connected i made sure of it

 

thanks for giving some info tho but is there anything else i should try to do?

 

how is the belt? Is it slipping??
Also check your fuses...there is one for alternator!

 

i didnt have my alternator belt tight enough once and it was only charging between 11-12volts, didnt make any noise just wasnt charging enough, use a pry bar on the alternator and tighten the **** outta it when ur done!!

 

i checked my fuses and they were fine my belt is brand new but i didnt check if it was tight yet i didnt even think of that thanks i am going to try that today

 

yeah i checked the belt today and it was was a little loose so i tightend it up and it was still at the same voltage it was before so i went to the store and bought some 4 gauge wire and i havent put it on yet but i think it might give it a better charge because there is a little dinky wire from the alternator to the fuse box

 

Its hard to do but, try checking for positive voltage right at the alternator. If you have 14V there and 12V at the battery, then you problem is the wire.

 

yeah i checked the voltage at the alternator and it was like 12.4 so it isent really putting anyhting out do u think it could just be a faulty alternator or do u think the signal from the ecu is bad and it isent putting out that much voltage

 

i read somewhere that the signal from the ecu that sends the alternator a signal to charge could be bad and i think it said you have to take one of the wires that go to the alternator plug out and if it charges then that means its bad has anyone heard of this before? by the way thanks for everyones help so far