Williams get back on track after reliability problems during the first three days
Williams veteran Rubens Barrichello closed the Jerez test by setting the fastest time on the final day.
His lap of one minute, 19.832 seconds was 1.242 seconds faster than Ferrari's Fernando Alonso and two seconds beyond Sebastian Vettel's Red Bull.
McLaren failed to set the times alight at their first test with the 2011 car with Jenson Button ninth on Sunday.
The teams continue their pre-season preparations in Barcelona's four-day test which begins on Friday.
Overcast skies greeted the 11 teams for the final day in Jerez but Barrichello, 38, cut through the mist to set his best time during an early flurry of fast laps.
A successful first morning in the Renault. A very full test programme, a great feeling, good pace but more work to do
The Brazilian's time was 0.520 secs faster than
previous best mark in Jerez for Mercedes on Friday.
Kamui Kobayashi was the second fastest man on track on Sunday for Sauber. The Japanese driver was 0.769 secs adrift of Barrichello, with Alonso further back for Ferrari.
"I'm very happy," Alonso said. "After four days here at Jerez, no problems for Felipe [Massa], no problems for me, so we are doing some very good progress.
"To see performance of the car and to evaluate how competitive we are, we need to do it Sunday after the first race in Bahrain. Then we will say the car is good or the car is not so good."
After a second day in the new McLaren, Button commented on his
page: "A chilly day in Jerez but still getting some useful laps in. Seems like everyone is running big fuel loads [in the] afternoon.
"Most teams are doing long runs. Interesting to see the tyre degradation from different teams."
McLaren sounded more despondent in a statement.
"Jenson was unable to find a suitable balance with the car," the McLaren statement read. "The team's progress was brought to an early end in the middle of the afternoon following the failure of an internal component.
"A frustrating day of running."
With Ferrari, Mercedes, Renault and Williams taking turns to top the timesheets in Jerez, the wait for a clear pacesetter ahead of the 2011 season continues.
Headline times do not tell the whole story in testing and it is difficult to make comparisons between the teams because it is not known how much fuel each car has on board or which tyres they are using.
The test has not been without its challenges. There are issues to be resolved so that we can maximise our track time for the remaining two tests
Mercedes team principal Ross Brawn
While McLaren's weekend programme was upset by a lack of parts and Mercedes were hit by yet more technical glitches, Red Bull and Ferrari will take comfort in the reliability of their cars in Jerez.
Ferrari duo Alonso and Felipe Massa notched up 463 laps between them while Vettel and Mark Webber clocked 396 laps for Red Bull.
"It's been a pretty solid test overall," Red Bull head of race engineering Ian Morgan stated. "We've got some good mileage and the car has been reliable."
On Sunday, Vettel smoothly ticked over 11 laps at a consistent pace of 1:23 per tour while Alonso split a longer run over 17 laps largely between 1:23s and 1:24s.
In comparison, the fastest man of the day, Barrichello, clocked a majority of 1:27s over a 17-lap stint while Button hit mostly 1:25s over a 20-lap run.
Although it is difficult to make exact comparisons, F1 insiders believe Red Bull and Ferrari are the quickest cars on track in terms of true pace.
Bruno Senna made his first appearance in a Renault, which was decked out for the coming season with a black-and-gold livery reminiscent of his late uncle Ayrton Senna's tenure with Lotus in the mid-80s.
Renault's top priority in Jerez was to evaluate a replacement for the injured Robert Kubica, who is
expected to miss the entire season
as he recovers from multiple fractures and a partially severed right hand sustained in a rally crash last Sunday.
Nick Heidfeld hopes to take Renault chance
Nick Heidfeld strengthened his case after quickly surpassing the fastest time set by Renault number two Vitaly Petrov during his two days in the car on Thursday and Friday to top
Renault team boss Eric Boullier has said he wants to give Senna, who made his F1 debut with Hispania in 2010, experience in the car but that he is looking for a more experienced driver to replace Kubica.
Senna finished the day fifth fastest overall. The Brazilian was a second slower than Heidfeld's best time on Saturday, although the track conditions were different.
"It was an awesome day," Senna stated. "I started the day pretty relaxed; gradually built up my confidence, and then by lunchtime I was feeling pretty comfortable with things."
The morning session in Jerez had been interrupted by three red flags in quick succession.
Virgin's Jerome D'Ambrosio was the first to stop out on track because of a problem with an oil pressure sensor.
Nico Rosberg ground to a halt in his Mercedes shortly before Kobayashi spun his Sauber into the gravel.
Mercedes changed Rosberg's engine as a precaution but the German lost nearly three-and-a-half hours of running before he was able to return to the track.
"The test has not been without its challenges," summed up Mercedes team boss Ross Brawn. "There are issues to be resolved so that we can maximise our track time for the remaining two tests."
Two more red flags interrupted the final hour as Barrichello and Force India's Paul di Resta stopped out on track.
"Unfortunately we couldn't do our final run of the day when something [the front left suspension] broke on the front of the car and I skidded into the gravel," Di Resta commented.
A late shower prompted a handful of drivers to scurry out to sample some wet running for the first time.
Hispania, who skipped this test, will reunite with the rest of the F1 teams at the Circuit de Catalunya on Friday to continue their pre-season programmes before the first race of the season in Bahrain on 13 March.
Second pre-season test, day four, Jerez de la Frontera, fastest times:
1 Rubens Barrichello (Brz) Williams-Cosworth one minute 19.832 seconds
2 Kamui Kobayashi (Jpn) Sauber-Ferrari 1:20.601
3 Fernando Alonso (Spa) Ferrari 1:21.074
4 Sebastien Buemi (Swi) Toro Rosso-Ferrari 1:21.213
5 Bruno Senna (Brz) Renault 1:21.400
6 Heikki Kovalainen (Fin) Team Lotus-Renault 1:21.632
7 Nico Rosberg (Ger) Mercedes 1:22.103
8 Sebastian Vettel (Ger) Red Bull-Renault 1:22.222
9 Jenson Button (GB) McLaren-Mercedes 1:22.278
10 Jerome D'Ambrosio (Bel) Virgin-Cosworth 1:22.985
11 Paul Di Resta (GB) Force India-Mercedes 1:23.111