Rep Power: 0

1 Month ago, my 1989 civic stalled while driving at 45mph, i suspected alternator was bad as the civic wouldn’t even crank. While replacing the whole starting system i noticed the PCM-Fi main relay fuse in the fuse box was blown. Car fired right up after replacing the starter. 1 week after replacing starter alternator and battery, it stalled in the road again. This time it was cranking but no start still. Checked the fuses and sure enough the PCM-Fi fuse was blown. I replaced the fuse and it started and ran for about 5 seconds and then shut itself off again. Now when i try replacing the fuse, it blows instantly after turning the key to position 2. The civic is swapped with OBD1 and has an mpfi injector swap. I’m not sure where to even start trying to diagnose this issue and not sure if anyone has had anything similar, suggestions would be appreciated.

 
Rep Power: 222

You have a short in that circuit, should be a pretty obvious one if it's blowing instantly. Figure out what wires come off that circuit and start tracing them