My views are these:
1. Knowing what questions to ask is already part of knowledge itself. The real problem with the sentence is the first part. "I updated the project" or "I did update the project" is not gery good English. We update a plan, a log book, a report, an announcement, the records, etc of a project but we do not "update a project". Can you think of a concrete example where it is correct, and meaningful, to say, "update the project"? What us the specific action involved?
2. "After talking to you" is indeed a correct option.
3. Alternatively, you could say, "I did X after I talked to you." Example, I did update the records after I talked to you.
4. "I did X after I've talked to you" is definitely wrong.