Can metallic smelling urine indicate dka? or is it usually just an infection?

Depends: Funny smelling urine is often hard to use as a diagnostic criteria; in fact, most guidelines recommend against using the smell or color of urine as part of clinical evaluation, as it is very subjective. What you are looking for are symptoms; pain/burning or fever (for infection), or large increase in urine output, increase in thirst, nausea/vomiting, abdominal pain (for dka).