Wire harness problem

I recently bought a 97 geo metro 5spd 1.0 liter and put a remanufactured engine in it. I was running good up until this electrical problem. In my opinion as the engine warms the wires around the engine and I think there must be a short somewhere. I had a metal screwdriver sitting near the headlight that started sparking to the frame of the headlight. Thats what makes me think its a bad wire somewhere. I tried checking fuses and they seem to be allright. I also tried a junkyard computer and it did the same thing. Can I remove the wiring harness without taking the whole engine out?

when the car is cold or just not been running I will start and run fine on occasion. then out of the blue it will have no power and just barly run then stop alltogether. Any suggestions? thanks