John Booth's Dinnington-based team revealed on the eve of the Australian Grand Prix that their car could not carry enough fuel to complete races.
The error will not be fixed until May's Spanish Grand Prix at the earliest, meaning Timo Glock and Lucas Di Grassi are unlikely to finish in Malaysia this weekend or in China later this month.
Technical director Wirth, who designed the car on computers at his Oxfordshire factory, said: "The chassis supplier is us – nothing to do with engine supplier or fuel supplier. We are fixing it for the team. We are not charging the team. It's our responsibility to provide cars that can finish. It's down to us."
Wirth is also negotiating his way around a fuel pick-up issue that means the Virgin cars are carrying more fuel in qualifying, making them slightly heavier than their rivals, chief among those being fellow rookies Lotus.
"We've got problem after problem," said Wirth. "We're a new manufacturer to Formula 1. It's not a team issue, it's us. We are not doing a very good job at the moment, particularly in qualifying, of picking up all the fuel.
"We could have qualified (in Australia) ahead of our main competitor if it was not for the fuel load. That's pretty frustrating – but that's why I'm actually quite calm."