The Coloni C3 had been designed by Christian Vanderpleyn for the 1989 Formula One season as a replacement for the FC188. Powered by a Cosworth DFR V8, it debuted at the 1989 Canadian Grand Prix with Roberto Moreno and Pierre-Henri Raphanel. The car struggled throughout 1989, often failing to pre-qualify, though it did achieve its best-ever qualifying position at the Portuguese Grand Prix thanks to revised aerodynamic work by freelancer Gary Anderson, who added a new nosecone and front wing after Vanderpleyn's departure.
Prior to the 1990 season, team owner Enzo Coloni struck a deal with Subaru, which bought a 50 percent share of the team with the aim of fielding a works car using its 1235 flat-12 engine. The flat-12, developed by Motori Moderni and originally intended for Minardi, produced only around 417 kW (559 hp), short of the 447 kW target, and weighed a substantial 159 kg for the unit alone. The complete engine assembly reached 112 kg once ancillaries were included.
Adapting the C3 for the new powerplant required significant changes. The airbox was removed and replaced by two sidepod-mounted air ducts, forcing the sidepods to become taller and longer. The heavier and bulkier flat-12 shifted the car's weight balance heavily toward the rear, producing unpredictable handling that handicapped the team throughout the season.
For 1990 Coloni ran a single car, driven by Bertrand Gachot. The team's pre-qualifying misery continued without interruption. Gachot finished dead last in pre-qualifying at the opening 1990 United States Grand Prix and failed to advance from pre-qualifying in every one of the eight races he contested with the Subaru-powered C3B.
After only eight rounds, the relationship between Subaru and Coloni broke down completely. Following what the team described as political wrangling between the two companies, Subaru withdrew its engines and sponsorship. Coloni reverted to the Cosworth DFR, this time prepared by Langford and Peck, in a revised chassis designated C3C. Although the C3C was closer in concept to the original C3 — reinstating the airbox and low sidepods — it still proved incapable of qualifying for a race in 1990.
The C3B episode illustrated the risks of building a Formula One car around an unproven customer engine, particularly one that was heavy and underpowered relative to contemporary rivals. The Subaru flat-12 gained a reputation as one of the worst engines of the normally-aspirated 3.5-litre era. Gachot went on to race the C3C through the remainder of the 1990 season before joining other teams, while Coloni continued to struggle with the C3C and its successor, the C4, until folding at the end of 1991.