Although there is no lack of studies on L2 motivation in applied linguistics, research on L2 writing motivation remains scanty. Drawing upon Dornyei's L2-motivational-self-system and the notions of identity, this study analyzed 27 Chinese university-based students' English writing learning experiences. Data were gathered through individual interviews and written reflections. The findings showed that the students' experience of learning to write was not conducive to their formation of identity as a multilingual writer because their ideal L2 selves in EFL writing were influenced by the overall learning and testing cultures. The findings also reveal that the teachers, parents, and schools played little role in shaping the students' ought-to selves due to the marginal status of EFL writing in both the nation-wide exams and the institutional curricula. Overall, the students' investment in learning to write yielded mostly a "passive and mediocre test-oriented"writer identity, with the capital to construct customized writings for individual and professional communication remained unattainable. The findings call for attention to the prevalent native speaker ideology and the ideology that considers students' L1 as problem.