I purchased a 1992 Suzuki swift, it had an old stereo in it and a switch to cut off the constant power wire to the stereo. I Removed the wiring harness and the cutout switch and rewired a clarion stereo harness with an inline fuse and noise supressor on the constant power wire. It will work perfectly fine like this for a short while and then pop the fuse upon ignition. I have tested the voltage on the constant power wire and there seems to be a spike in voltage on ignition and I beleive this to be the cause of my problem. My question is what can cause such a jump in voltage on startup?