https://www.avvo.com/legal-answers/how-to-i-get-my-car-buyer-to-put-the-title-in-his--3978347.html
“you might file an action for claim and delivery to get poseession of the car. At least if you do this, that might prompt the individual to either file the title with the Secretary of State or bring him/her to the table to deal with the title issue.”