Alternator seems to not be charging

[slider92571]

All of a sudden my 91 GSX wont start. I have jump started it and the minute you remove the cables it stalls unless you let the cables on along time and then it takes time until the battery discharges. Also I am not getting the alternator idiot light and the parts store said that they had notes on this that it could be an blown fuse in the lamp circuit causing it not to charge. I have never heard of such a thing. Any info would be greatly appreciated. If it could be something this simple, it would be great. I would rather not buy a new alternator and it do the same thing. Thanks in advance.Oh and my car is not modified besides exhaust, turbo timer, MBC, and upper ic pipe, and K&N filter

 

[chickmagnet]

Mine did the same thing no light but the alternator was indeed dead. Sounds exactly like what happened to me. My dummy light also never came on.

 

[just2asian]

sounds like, it's time for a new alternator.

 

[blackbyrd]

There is an 80a alternator fuse, on your main fuseblock, check that. After it jumps, take a multimeter and take a reading from your battery. It should be 14+ when running at idle. Try turning on your lights and see if it goes down real quick and comes back. If its not 14+, go take a reading down on the alternator positive out, and ground on the chassis, if that's not 14+, you need a new alternator.
You can also check your battery by taking a voltage reading on that, but since it's died I doubt itll be much higher then 10-11. You can take readings over a period of time, to see if your battery is being drained also.

 

[slider92571]

Thank you all for your answers. I have check the battery voltage and it is no where near 14+V. So I figured I needed a new alternator. When I called about one and they mentioned that it could be a blown fuse in the lamp circuit causing it not to charge and also not having the idiot light. I never heard of this before and was wondering if anyone has and if so which fuse are they talking about, the gauge fuse or some other fuse. Thanks for your help.

 

[silvercoupe97]

Thank you all for your answers. I have check the battery voltage and it is no where near 14+V. So I figured I needed a new alternator. When I called about one and they mentioned that it could be a blown fuse in the lamp circuit causing it not to charge and also not having the idiot light. I never heard of this before and was wondering if anyone has and if so which fuse are they talking about, the gauge fuse or some other fuse. Thanks for your help.

Battery voltage with the car off is around 12 volts and, as stated, 14 volts at idle. It sounds to me like those guys you called were referring to the fusible links. Have you checked those? According to the book, there is some sort of circuitry showing a relay connected to the light, check that too. Have you checked to make sure the bulb just isn't blown? That light should go through a self test (not the light itself but the charging system, which includes....) and it should light up when you first start the car.

I'm not going to type it out again so I will just link another alternator thread with what I suggested, to you...post #3