Manor CEO Graeme Lowdon admits he is not quite sure when his cars will hit the track in Melbourne, saying "there are a lot of issues".
After months of uncertainty, the Banbury-based squad finally confirmed at the start of March that they would run at this weekend's season-opening Australian Grand Prix with Will Stevens and Roberto Merhi named as their drivers.
They made it to Albert Park on Thursday, but neither cars took to the track on Friday due to software problems, and Lowdon concedes they have several problems.
When asked when his cars will be ready, he is quoted as saying by Autosport: "I honestly don't know. But what I can guarantee you is that, in terms of commitment and rate of problem-solving, we will be absolutely flat out.
"It's not simply a software issue, there are a lot of issues, none of which are a big surprise when you consider the amount of work that has been required to get the team here in a very short space of time.
"The problems that we are dealing with at present are not unusual for the task that we are doing, which is effectively setting up both trackside and on-track infrastructure for both of these cars to run.
"We just have to deal with the problems one at a time.
"I think as we steadily get through them we will be able to put a little more accuracy on any kind of prediction.
"At the moment, it's very difficult to predict because they are binary problems, things either work or they don't work."
Meanwhile Ferrari are still owed money from Marussia for supplying engines last year and team principal Maurizio Arrivabene says they are open to helping out the team.
"Last year, we deal with one company and we are still working to get back our money as everybody knows," said Arrivabene.
"Now we are dealing with a new company so it is a completely different story.
"We are doing our job now to support them also because they show to us that they stick to what is agreed in the contract and they are serious.
"I said to Graeme in a very simple way, we are more than open to help you but no money, no honey."