If you're looking for synonyms for the phrase "starts up," you can use words like initiate, begin, launch, commence, inaugurate, activate, fire up, kick off, and get going. These words all convey the idea of starting or setting something in motion. For example, you might say "She initiated the project" instead of "She started up the project," or "We need to fire up the engine" instead of "We need to start up the engine." Using synonyms can add variety to your writing and help you avoid repeating the same word or phrase multiple times.