Engineering education has widely adopted project-based learning (PBL) because of its effectiveness in developing students' capabilities to face society's current, complex challenges. However, both students and professors are challenged while adopting PBL. These challenges increase when students' technical and social backgrounds are highly heterogeneous within a course, as seen in many Latin American engineering faculties due to economic and social inequalities. Using the case of an engineering faculty from Latin America, in this study, we examine specific barriers caused by students' social heterogeneity and how professors handle these barriers in fresher courses. Specifically, we propose that heterogeneity generates asymmetries in students' technical backgrounds, social competence, and engagement, which professors address using scaffolding, teamwork, and identification mechanisms. Theoretically, this study partly reveals the particular dynamics that engineering professors face in Latin American countries. Alternatively, from a practical standpoint, we provide engineering professors with insights into implementing PBL in these environments.