SAKHIR, Bahrain - Red Bull's pre-season problems showed little sign of easing in 2014 Bahrain testing on Wednesday (Feb 19) with four-times world champion Sebastian Vettel managing only 14 laps on the first day.The Renault-powered team, which did the same number of laps over four troublesome days in January 2014 in Jerez in southern Spain, said a mechanical issue sidelined Vettel at the Sakhir circuit.'WE'RE NOT HAPPY'Vettel said: "We're not happy with where we are and we have a long way ahead of us. The first gut feeling from the car is OK but we need more running. It's not easy to find a quick fix but I think we understand the problems. We sorted out the issues from Jerez and we were able to do some laps but very often you fix one problem and another pops up - which is what happened."F1 has a new V6 turbo power unit with energy recovery systems for 2014, replacing the old V8 engines. Vettel said: "We all knew 2014 was a massive challenge and we are working flat-out to solve the problems."Renault said ahead of this the second four-day test of 2014 that it was making good progress on the faults that plagued teams in Jerez.HULK THE FASTESTRed Bull's race engineering co-ordinator Andy Damerum reported a big improvement since Spain but the team was playing catch-up with rivals. He said the issue on Vettel's car was unrelated to the problems in Jerez. Nico Hulkenberg was fastest on the first day for Force India; he did 78 laps. He was followed by Ferrari's Fernando Alonso (64), and Mercedes' Lewis Hamilton (74). Hamilton said: "It's been impressive to see us start the Bahrain test with good mileage and reliability especially when you see how difficult it is for everyone with the new regulations."McLaren's new Danish recruit Kevin Magnussen put in 81 laps and was fourth-fastest.Lotus showed off its new Renault-powered car with its twin-prong nose but had teething problems after missing the Jerez test. Romain Grosjean managed only eight laps. Trackside operations director Alan Permane said: "It's no secret that we're frustrated. We want to get laps on the board to understand our new car and all the different elements it contains."Renault-powered Caterham fared better - reserve driver Robin Frijns managed 68 laps.