Two weeks after the Jerez calamity, the reigning world champions are back on track in Bahrain with designer Adrian Newey and Renault's fixes in place.
However, over four hours into the first day of the second official pre-season test, German Vettel had not even turned a lap.
"The car was still being assembled," said German correspondent Michael Schmidt.
"New parts were still arriving from England," he told Auto Motor und Sport.
The first public glimpse of the unique double-nosed 2014 Lotus, which also features an asymmetrically-positioned exhaust, can be seen here:
The asymmetrical exhaust image is here:
"I'm not saying that we have solved all of our problems," said Renault Sport's Remi Taffin, "but we should have a firm grip on what held us back at Jerez.
"We now have a base on which to build. Bahrain is our first test.
"Yes we could still have some problems, but we should be able to build upon this basis," he added.
Even Red Bull's always-blunt Dr Helmut Marko was on Wednesday not pointing the finger of blame in Renault's direction.
"Even if there had been no problems with the power unit," he said, "we would not have been running much in Jerez.
"It was our fault. Under the cover it was getting too hot, so we have brought two solutions here to Bahrain, which should help us."
At about 2pm Bahrain time, Vettel emerged from the pits for an installation lap, and he soon followed it up with an initial run of four laps.
Meanwhile, a photo of former Lotus boss Eric Boullier in McLaren grey in Bahrain can be seen here.
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