The car - dubbed "pretty" by team boss John Booth - still has not been seen.
Jan.30 (GMM) Deep into the penultimate day of testing at Jerez, and Marussia's 2014 car is still yet to see the light of day.
Having solved a niggly technical glitch at the factory, the backmarker team rushed the unseen MR03 to Jerez on Wednesday.
On Thursday morning, the launch press release went out, as Marussia said on Twitter the car was preparing to make its debut on a "cool but clear morning".
Hours later, the car - dubbed "pretty" by team boss John Booth - still has not been seen.
It is yet another sign that the ultra-complicated rules for 2014, featuring turbo V6 engines and powerful 'ERS' systems, has caught out even the smartest minds in global motor racing.
World champions Red Bull and Renault's problems seemed also to have persisted on Thursday, when Daniel Ricciardo made his debut in the troubled RB10 but was soon standing trackside next to the smoking car.
"Tactically we're taking the 'less is more' approach," Red Bull joked on Twitter.
This time, however, engine partner Renault was not to blame.
"This (problem) is our own responsibility and has nothing to do with the power unit," Dr Helmut Marko, watching Thursday's proceedings at Jerez with his boss Dietrich Mateschitz, told Germany's Auto Motor und Sport.
A big crowd has gathered at Jerez on Thursday, mainly to see Spanish hero Fernando Alonso drive the Ferrari for the first time.
The red car duly stopped on track.