Unplugging the tank only kills the gauge. Don't assume anything when it comes to electrical, relay could be good or it could be stuck in the on position. Verify the relay and use a 3-5 psi pump, the points in the OEM are easy to change. The aftermarket pump may not have points at all. Whatever the reason for the smoke, fire and gas make a bad situation so I'd pull that pump and make sure what you have.