to put all of ones heart into a business (see Molina)
Alonso de Molina:
itlan naqui. (pret. oitlan nac.) poner pecho alos negocios. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 43r. col. 1. Thanks to Joe Campbell for providing the transcription.