Hi
I have a 1990 s13 fastback with a manual trans. I bought the car with the promise of a bad fuel pump. I replaced the fuel pump and boom she drove. I parked the car and after a couple days she now only cranks. I thought it was a bad pigtail harness to the fuel pump after confirming the pump and fuses and the relay were good, so i cut it out and soldered in wire to replace it. It still doesn't start, only cranks. I looked at the computer in the 3rd section to see if it threw any codes and it did not. I'm not sure what to do from here so thats why im posting. Any ideas?

UPDATE: so i went ahead and tested the power to the fuel pump. On the power wire all the way up to the fuel pump assembly, there is power. I have tested the solder point on the other side of the fuel pump "lid" and its 0 volts. Any ideas?

UPDATE :

So after tracing tons and tons of wiring, I found a short to ground between the relay and the 10A fuse. So I put spliced in new wire between the three BLK/WHT wires. After that, I was getting voltage to the relay. Despite this, with a new relay it still doesn’t start. Here is the part I’m confused on. If I take 16gage wire and complete the circuit the car starts up and runs. What’s my issue? I’m thinking something with the ECU but I’m not sure and haven’t found a ton of clear info