It's rare to use the future tense with *if*. Speakers would use either the past tense or present as follows:

> Would I fail if I didn't study?
>
> Will I fail if I don't study?

It's more common to use the present tense ("don't study") when the main clause has "will" (future).

Of thes two alternatives, the first tends to indicat a more "hypothetical" suggestion: it's asking about possible universes, whether or not you actually have any intention of studying. In the second case, there's a presupposition that you're actually considering studying.