I've decided that whenever I do my masters it will be in a math related field ( Act.sci or stats or whatever.). Will my Engineering background hurt me when I apply again for a pure math/stats degree?
Do you want to study something in the actuarial science or statistics area, or are you interested in pure math? Your engineering background would put you at a huge disadvantage if you were interested in pure math, but you should have a good quantitative background for applied math fields like statistics or actuarial science.
My understanding is that most statistics or actuarial science programs don't care much about the math subject GRE. A good score might help you, but not submitting a score won't hurt. The math subject GRE is targeted at students who want to pursue graduate school in pure mathematics. It assumes that you have taken courses in real analysis, abstract algebra and topology, for example. You probably have not studied these subjects as an engineer, but you also don't need them for actuarial science.