Smoking Sub!!!!?

Ok, I have a kenwood kac-9103d amp 900w x 1 at 2ohms and 2 kenwood kfc-3011w 4 ohm SVC 400w rms each, i have them wired at 2 ohms and i know that everything is wired right, and gain is set at 2 volts which is my HU's preout voltage, every thing worked perfect for 2 months until i added a 1.5 farad capacitor yesterday and i popped the trunk after a 15 minute drive with playing it loud and my box was smoking from the port, i felt the speakers and just the left one was a lil warm, this is how i wired the capacitor, + wire: battery(fused) to capacitor postive to amp, - wire: capaitor negative to ground, same as amp. Any answers will be greatly appreciated!!!!!!!!!!