Chaves was scheduled to race for the full season but the Portuguese driver failed to pre-qualify for every race he entered. The car was out of date, fragile and hard to handle, and Chaves was relatively inexperienced. Along with four other teams, Coloni was forced to participate in pre-qualifying sessions early on Friday mornings, and Chaves was one of eight drivers taking part in those sessions. At the season-opening 1991 United States Grand Prix, Chaves posted a faster time than Olivier Grouillard and Eric van de Poele, but crashed into a tyre wall during the session. He outpaced only Grouillard in Brazil, and a broken gearbox left him slowest in San Marino. In Monaco he again had only Grouillard behind him, and he was slowest by nearly eight seconds in Canada, despite the new Brian Hart-prepared engine.