Dr Helmut Marko thinks Red Bull's reliability problem will be solved by the time the 2022 car returns to the asphalt this weekend at Imola.
World champion Max Verstappen has been left trailing in the championship after two powertrain-related failures in the first two grands prix.
"It wasn't the engine itself that was the problem, it was the fuel delivery," Marko said.
"The fuel line burst under high pressure," he told ORF. "We think that had to do with the porpoising. According to Honda, we can count on the problems being resolved before the next race."
Former F1 driver Marc Surer thinks Red Bull may have been caught out by the shortened development time after duelling with Mercedes for the 2021 title.
"The fact that a line breaks means either that the part was too weak or it was not properly designed," he told formel1.de.
"Or, and this is what I think, is that the assembly was sloppy."
The good news, according to Marko, is that Verstappen is coping well with being so far behind after just three races - even though he was obviously frustrated after Melbourne.
"Sometimes he still lacks the confidence with the setup of his car to maintain his extreme driving style," the 78-year-old Austrian explained.
"You can see that Sergio Perez is closer to him than before, but Max is a lot calmer than before anyway.
"After he retired, he returned to the box and we discussed everything calmly.
"But if we don't win again soon, he is indeed a time bomb."
Verstappen, 24, is all signed up on a lucrative contract all the way to the end of 2028 - long into the post-2026 era in which Red Bull may join forces with Porsche.
"Looking at '23, '24, '25, I can say that we are still discussing whether Honda would like to continue our existing relationship," team boss Christian Horner revealed.
Then, for 2026, Red Bull will take full control of its own engine facility called Red Bull Powertrains.
"That is certainly what we are looking to do for 2026," Horner confirmed.
"Besides Ferrari, we would be the only team in Formula 1, and certainly the only one in the UK, to do everything in one location under one roof which is very exciting."
