I have a 1990 S13 hatch with a turbo KA24E, 550cc injectors and a relocated battery. I have a 0 gauge wire running from the positive to the engine bay, and a 0 gauge to the strut tower and a walbro 255. The problem I'm having is it seems like the fuel pump is drawing a lot a power when I'm trying to crank the engine. I believe this because when I remove the fuel pump fuse the car cranks normal and strong. With the fuse in, it really struggles to turn over and start. I've had to start it plenty of times by cranking the car, removing the fuse, starting it, and run out and put the fuse back. Does anyone have an idea what's going on? Should I get a better stronger battery? Should I wire the fuel pump directly to the battery? More grounds? I'm really at a loss here and anything helps.

You gotta have something seriously awry there in wiring. No way for a pump to override a starter in amp draw any other way. Or the battery is weak as hell.

You need at the least a ground from the frame (strut tower) to the engine.

That's what I'm saying, I'm thinking of added another fat ground to the engine and see if it does anything. And probably just get a diesel battery and call it good.