I wasn't wanting to get too deep!
Remembering the claims are fake science, I was assuming the ionizing claim meant they would strip an electron and become very weakly paramagnetic (given the size of a hydrocarbon chain), much like an H2O molecule. They would then "line up" for better burning. Or that the jerk would spin them, again for better burning. Or the magnet would make them dance the waltz, which again, we all know leads to better combustion, cleaner intakes, the Swedish Bikini Team to parachute into my hot tube one snowy winter (in Tucson), and world peace.
To steal from Wikipedia:
Paramagnetism requires that the atoms individually have permanent dipole moments even without an applied field, which typically implies a partially filled electron shell. In pure paramagnetism, these atomic dipoles do not interact with one another and are randomly oriented in the absence of an external field, resulting in zero net moment
I'm quite a bit farther out of chemistry than you and open to correction, even then I only had to take the basic courses. Still, you got me--free radicals and ions aren't the same; I was taking liberty (ions can induce radicals). I also don't recommend putting broccoli in the engine, or expecting a vehicle magnet to ionize your fuel.
ò An ion is an atom, group of atoms, or subatomic particle with a net electric charge (positive or negative)
ò A radical is an atomic or molecular species having an unpaired, or odd, electron. Some radicals are relatively stable, but most are very reactive.