if the wire insulation has started to crack, the best solution is to replace it all. You can never tell where the next crack or frayed wire will be and what problems it will cause. For only a temporary measure tape cracked or frayed wires so you can get the car running and improve performance. Do NOT bypass the fuse, it is your only soruce of protection, if it blows replace it with another of the same size, if the replacement blows, do not run the car get the problem fixed.