Defending Dakar Rally champion Nasser Al Attiyah was forced out of the 2012 edition on Tuesday when his temperamental Hummer broke down again, organisers reported.
The 31-year-old Qatari driver has been plagued by problems since the start in Mar Del Plata on New Year's Day.
He lined up for Tuesday's ninth stage in sixth position overall, eight minutes behind leader Stephane Peterhansel, having struggled to make up the loss of 10 minutes on the opening stage.
Al Attiyah, who is hoping to compete in his third Olympic Games in shooting at London 2012, lost more precious time when he was forced to make three unscheduled stops on the 556km run between Antofagasta and Iquique.
Initial reports suggest his American-backed Hummer had suffered problems with its alternator.
He decided to call time on his title defence at the 174km mark of the timed special in a race in which, despite his mechanical gremlins, he still managed to post the fastest times in the second and seventh stages.
Among the catalogue of mechanical setbacks he has suffered have been a broken radiator and an errant spare wheel.
Despite that he had appeared upbeat at the end of Monday's eighth stage, declaring; "I know everything is going smoothly, and we will see how far we can go."