Red Bull's pre-season problems showed little sign of easing in Bahrain testing today with four-times world champion Sebastian Vettel managing only 14 laps on the first day.
The Renault-powered team, who did the same number of laps over four troublesome days in last month's first test in Jerez, said a mechanical issue sidelined the German.
Formula One has a new V6 turbocharged power unit with energy recovery systems this year, replacing the old V8s, and Renault have had more problems than Mercedes and Ferrari in getting their teams up to speed.