SCHEMA:
CREATE TABLE table_name_83 (grid INTEGER, laps VARCHAR, time_retired VARCHAR, driver VARCHAR)
USER:
What is the grid total that had a retired for engine, teo fabi driving, and under 39 laps?

QUERY:
SELECT SUM(grid) FROM table_name_83 WHERE time_retired = "engine" AND driver = "teo fabi" AND laps < 39