YOU SAID:
Moniko mechaniced Monika's engine
INTO JAPANESE
モニカはモニカのエンジンを整備した
BACK INTO ENGLISH
Monica serviced Monica's engine
INTO JAPANESE
モニカはモニカのエンジンを修理した
BACK INTO ENGLISH
Monica fixed Monica's engine
INTO JAPANESE
モニカはモニカのエンジンを直した
BACK INTO ENGLISH
Monica fixed Monica's engine
That didn't even make that much sense in English.