Sometimes in an intensive narrative the present tense is used to refer to past events. Such use of the present tense is called praesens historicum. It is formally present but semantically past. How does consecutio temporum of conjunctive subordinate clauses work with it? Should I use present and perfect conjunctive (as if praesens historicum was present) or imperfect and pluperfect conjunctive (as if praesens historicum was a past tense)? If both are possible, is there a difference?
In English, your consecutio temporum is usually called the ‘sequence of tenses’. There is a general rule that in the principal sentence (i) a primary tense is followed in the subordinate clause by a primary tense, and (ii) a historic tense by a historic tense. In subordinate clauses the subjunctive is usual, incomplete action being represented by the present and imperfect, and completed action by the perfect and pluperfect. The historic present (praesens historicum ) and historic infinitive are mostly used with historic sequence.
There are exceptions, though — e.g. to avoid ambiguity, or in a consecutive clause if it describes a completed action; and in oratio obliqua, conditional statements have a different set of rules.
This is a tricky business in English, too — look at the difference between, for example, I would have liked to see and I would like to have seen, and you may reflect that a majority of speakers rely instead of either of these on I would have liked to have seen, without regard for the niceties of good grammar.
Tuomo Pekkanen's Ars Grammatica – Latinan kielioppi (§116, lisäys 3) mentions that the historical present can be treated as either a present tense or as a past tense when consecutio temporum is concerned. It gives this example without any citation or further explanation:
Quod cum videret, quaerit, quae causa sit/esset.
When he saw it, he asked what the reason was.
I know this is not very convincing evidence, but it does support the idea of two possibilities.