91 Si Hatch
JDM B16a Crate Engine w/ y1 trans
P28 ECU

Just bought a B16a swapped EF civic, owner threw on an eBay turbo kit after listing but didn’t tune, I removed intake clamp and drove home under 3k rpm with radiator fan on, drove fine but after 15min on freeway started overheating (all the way to H), 5min later got home and it was still running hot just idling.
I ordered Sk2 Half Rad and 14” Fan. (Figured I’d just replace everything to be safe). This morning I went to swap radiators, drained coolant and filled with water so I could flush the system, went to start the car and battery was dead, jumped battery, 5 min later tried to start: all electronics came on, heard fuel pump click, starter clicking, everything sounded normal but it wouldn’t turn on.

What is my next step?
What could be the problem?
any and all help welcomed!

 

Is that a chipped p28? You could get a p30 to be proper since your converted to obd1, also your "starter clicking" would point to it not getting enough power to get it to do its job. Since the battery has been relocated, make sure your grounds are making clean bare metal contact.
As for overheating, your rad placement is not good being where it is.. poor airflow getting to it.
Make sure the fan is turning on. If it's not, check the fan switch by jumping its plug connector pins, if that works and the fan turns on then you just need to replace the sensor. If that doesn't work, check for continuity at the fans plug going to its motor, if none then the wires may have a break leading to the fan motor.
If that all checks out fine, you could do like I did and get some exhaust wrap and do the exhaust manifold and down pipe also get a turbo blanket to aid in keeping the heat from soaking the rad.
I bought a cheap ebay turbo blanket (decent quality for $30) and had to do a couple short heat cycles to break it in because it smoked like crazy on its first short run then better its next, now it doesn't smoke at all and works great. I can put my bare hand on the exhaust right after getting off the hwy.

 

Charge battery longer or use a jump pack.

Make sure transmission grounds are there/good.