Okay before someone tells me to test my alternator hear me out.
So first my car ran great. Never had any real problems after 3 years of ownership with autocross and drag racing and even some rallycross periodically. (Car is an 89 240sx with a '92 KA24DE swapped in).
I drove through the city with my perfectly working car and hit the largest pothole of my life. No joke I've been driving on crappy roads for 6 years and this pothole gave me goose bumps when I saw it. I nailed it with my front right tire. Rim and tire were fine (I have a lot of sidewall for cushion) and 30 minutes later I began getting signs of a bad battery; dimmed lights, studdering under acceleration etc. Car dies and I try to jump it. No luck.
1) I swap in a battery from my truck and it works fine. 2 days later the car is dead again. I jump it and check the voltage across the battery with a volt meter. I watch it start at 12.9 and steadily plummet until the car dies at 9 Volts. This takes about 20 minutes with no accessories on.
2) Now, I visually check the alternator fuse and see that it is fine.
3) Next, I check the alternator connections (3) they are bolted tightly.
4) I do a quick visual inspection of the wires and see that they are also fine but am not very thorough.
5) I speak to the people at the auto parts store and they say at a cell may have broken off of the battery from the pothole and caused my battery to surge and kill my alternator (which was only 1.5 years old with maybe 1000 miles on it). I replace the alternator with a high quality BRAND NEW one and jump the car again. SAME PROBLEM. Voltage starts at 12.9 and steadily drops as if the alternator is not even there.
6) By now I know it must be a break in the wire somewhere. So far all three wires have been traced about 1.5 feet where they disappear back into the loom located by the fuse box. I will more thoroughly check them entirely tomorrow so look for any breaks that I may have missed.
What am I missing here? Is there a simple solution that I have overlooked?
*I do not know how to run continuity tests. Should I do that and how should it be done?
Any help is appreciated. Thank you