AGS appeared with a car that was once again penned by Vanderpleyn. The JH21C was a strange mixture between former AGS F3000 vehicles and Renault F1 parts which were used extensively. The car was powered by a well-used Motori Moderni turbo engine (the only time these Carlo Chiti-developed engines were given to a customer team) and driven by Italian Ivan Capelli. A few weeks before, the car had been tested at Paul Ricard by Didier Pironi, driving an F1 car for the first time since his leg-breaking accident in the 1982 German Grand Prix. Due to technical difficulties, neither in its first attempt nor in the following race in Portugal did Capelli see the finish.