Early in the 1984 season, Ayrton Senna recorded his only failure to qualify for a Formula One Grand Prix. At round four of the championship, the San Marino Grand Prix at Imola, Toleman decided not to run their cars during Friday qualifying after to a dispute with tyre supplier Pirelli. Senna then suffered a fuel pressure problem in the wet Saturday session which left him stranded on the far side of the circuit between Tosa and Piratella. He was unable to make it back to the pits in time to qualify for the race, his best time of 1:41.585 being 13.068 seconds slower than the time defending World Champion Nelson Piquet had set in his Brabham-BMW to claim pole while being 2.637 seconds slower than 26th and last qualifier Jo Gartner.