For some context, my 2000 Ap1 will not start, I hadn't driven it in about a month, and when I went to turn it on, the battery was obviously cooked for some reason. I am not sure if I or someone left the key in the ignition, a light on, etc... Nevertheless, the battery was outputting very low voltage. I jumped the car and let it run for a while, and with a multimeter I could see that the battery was not taking a charge, the alternator is outputting enough energy as well. After getting it to run from jumping it, I tried jumping it again and it would not start. So I bought a new battery. It still would not start even with the proper voltage from the battery and a little extra from a battery jumper pack. When the key was inserted and turned, my Haltech CAN gauge (Hooked up to a Platinum Pro Plugin) would turn on and give readouts. In the process of trying to figure out the issue, the can gauge suddenly stopped working and I can not see the indicator light(if there is one) lit up on the ecu. The Battery is still outputting the correct voltage, at this point I have no clue what the issue could be. Any suggestions would greatly help!
Specs :
-Haltech Platinum Pro Plugin with wideband
-ID1050 Injectors
-FX300 Clutch
-Ohlins DFV coilovers w Sake Bomb lower rear forks
-T1r 70mm Exhaust
-Koyo radiator
-Haltech Can Gauge
-Newish spark plugs

 

Have you checked your main/battery fuse You might of popped it.

 

I have not but the dash gets power so I didnt think it would be the main

 

Not the main of dash gets power.

One troubleshooting technique is to keep working forwards. There is voltage at battery, check, thereis voltage after main fuse, check. Keep going forward through the circuit rhat feeds whatever isn't getting power. Find convenient places along the path that allow you to get meter leads to take reading. Find the place where there is power before that point, but not after.

Now you've found the right haystack, time to dig in to look for needle. Sometimes that will be obvious. Of not, got to get creative how to narrow down between last point with power, and next point without. Where you can take readings to narrow down further. Meter needle probes that you can piece wire insulation with strippng wire super helpful (hole seals back up when you remove probe).

Obviously you'll need a wiring diagram to do this. You'll also need the basic skill of translating a wire diagram that shows every wire in a square grid like map to the actual nest of snakes that is the cars harnesses. Just don't get intimidated and think it through.