Background: Engineers must learn to document their process to communicate effectively in teams--a skill that calls for knowing "how" and "when" to capture information, as well as the self-regulation to continually engage in this practice. Motivation to self-regulate requires that students be motivated to complete a goal and see value in the practice toward accomplishing that goal, raising the question of how students' experiences while participating in an engineering design task impact their motivation to self-regulate their documentation practices. Purpose: The purpose of this study is to explore the sequence of events that lead to changes in students' "motivation to self-regulate" documentation practices to support their design process. Method: We use Organismic Integration Theory on the phases of intrinsic motivation to self-regulate as a lens in a case study to capture the collective growth of a high school engineering design team collaborating over the course of a semester-long drone design challenge. Results: Findings demonstrate that both "successes and failures" played an intimate role in increasing intrinsic motivation to engage in self-regulatory practices, as increased motivation to see their drone fly pushed students to question the role of documentation in the design process. Conclusion: When high school students work on intrinsically motivating projects with opportunities for both successes and failures, they can learn to self-regulate documentation practices. We discuss the implications for instruction and research in turn.