How do i get Ion Engines to work?

your battery is too small then

If it puffs only then check your battery, those suckers drink watts like there's no tomorrow

Are the ion engines attached to the xeon tank? I can only get them to work when directly attached to the xeon tank, even if they're both attached to each other and "fuel line" is on.

@Insanity yes

Do you have xenon gas and a battery?