JEREZ, Spain - Renault, engine supplier to reigning Forrmula 1 champions Red Bull has admitted it kicked off F1's radical new V6 era with a significant problem."Obviously we do (have a problem)," the French brand's Remi Taffin told reporters at Jerez on Wednesday after Red Bull's No.1 driver Sebastian Vettel left the southern Spanish circuit with only a handful of laps completed; Mercedes and Ferrari-powered rivals collected far more mileage."Annoying!" Red Bull's Dr Helmut Marko told Bild newspaper. "The problem is in communication between the two kers (kinetic energy recovery systems)," he explained. "So, as in a computer, the hardware and software are not working with each other."'RATTLING LAWN-MOWER'Also struggling are Renault's other F1 customers, including Toro Rosso, Red Bull's sister team whose new STR9 never left the Jerez pits. Caterham was also affected.Veteran F1 correspondent Roger Benoit said in Blick newspaper: "The (Renault) cars sound like rattling lawn-mowers. Renault was even thinking about not coming here."Taffin, however, was confident the problem could be fixed. "We have the parts, we have the people, we have the means to solve the problem. We are confident that on Thursday (Jan 30) at 9am our customers will take to the track."HORNER WANTS EXTENSION?With crucial track time lost, however, Red Bull is looking ahead to the second test in Bahrain. Team boss Christian Horner played down the impact. He told the F1 website: "Our expectations coming into this test were purely system checks -- the proper testing will be in Bahrain."Horner denied Red Bull was already pushing for the Jerez test to be extended into Saturday but there were also rumours Renault was paving the road for a delay of the International Automobile Federation's 'power unit' homologation deadline.But he also admitted: "We will be relying extremely heavily on our engine partner." Stay with Wheels24 for the 2014 F1 season – fresh reports every day.