1996 240sx Charging system failure

[neekap2]

My S14 just died the other day and I discovered that the battery was dead and the alternator was not charging it at all. I was able to jump it fine, but once the jumper cables came off it died. I had the alternator tested at Autozone and it appeared to be working fine.

No fuses are blown, and testings with the multimeter reveal that when the car is on, the voltage on the battery just drops pretty fast, and the same is for the alternator. If it can be assumed that a working alternator is being used but it is still not charging the battery and the voltage is dropping, what else could be causing this problem?

Another possibly related problem is that when trying to start the car, it will often click once and then not start cranking for about a second, and sometime it will just click once and you will have to retry turning the key. Now the battery is low and it will click rapidly and if it tries to crank at all, it will be very weak. Now, when the ignition is set to Accessories, everything works and the voltage on the battery reads ~12.4V, when turning to ON it dips below 10, and trying to start the car causes it to dip further, even though it does not crank anymore.

To sum it up, the battery is tested to be fine, the alternator is fine, fuses and fusable links are not blown, and the wiring appears to be fine from what I can tell. The car runs and starts fine when hooked up via jumper cables to another running car, but as soon as they are removed the voltage starts dropping and it dies. I was told that perhaps the starter could be draining voltage due to an internal short, but I am not sure about that. Any help? 1996 240sx

[PhantomS13]

the starter could be the problem, but that would only cause a parasidic drain, draining the battery slowly while the car is off. it sounds to me that you have a bad connection either from or to the alternator. i'd start by checking the ground from the alternator. maybe its corrroded or been painted or something stupid. let me know if that helps

[neekap2]

bingo, it was the alternator ground, luckily an easy fix

[rogoman]

You probably have a short somewhere in the charging system.

[PhantomS13]

sweet, glad you got it