Nick Heidfeld insists BMW Sauber are not yet ready to throw in the towel but admits title hopes are fading fast.

The team's start to the new F1 year has not been as disastrous as for Ferrari, but it has not fallen too far short.

BMW Sauber have just four points to their name thanks to Heidfeld's runner-up finish in the rain-affected Malaysian Grand Prix.

As for team-mate Robert Kubica, he has gone from title challenger last season to bit-part player this, with the 24-year-old yet to score a point.

After an accident in Australia with Sebastian Vettel when pushing for a podium place, an electrical fault led to him failing to get off the line in Sepang.

In Shanghai last Sunday, Kubica qualified a dismal 18th prior to a spectacular shunt with Toyota's Jarno Trulli which sent the Italian out, yet somehow the Pole managed to keep going, finishing 13th.

As with Ferrari, these are worrying times for the team and there is a danger they could soon be cut adrift from the leaders.

"Hopefully from Barcelona (Spanish Grand Prix on May 10) we will have a good car to win back some points compared to the others," said Heidfeld.

"Firstly because the advantage they have, especially Brawn and now also Red Bull, is quite big in lap times.

"If we make a good step it might bring us closer, hopefully to the front of the midfield. But obviously I don't know how it's going to be.

"It's unlikely we will just catch up with them because they will be developing their cars as well.

"So you cannot say we are out of the running. We're still fighting very hard and anything can happen.

"It (the championship) is getting more and more unlikely, although I wouldn't rule it out."

Heidfeld feels the root of the team's problems surrounds a lack of updates in the opening races when it became apparent they were off the pace and struggling.

"We didn't have enough new parts in those first couple of races," assessed the German.

"During winter testing we were quite happy with our pace, although you never know how much fuel the others have.

"You analyse the data and the lap times and we thought we were in a good position. But then I think we just lacked development.

"It's been tough, but it doesn't change the way you work, which is the most important thing, and the target remains the same: to fight for the championship.

"It's no use crying or moaning about what happened, you just need to keep your head up and achieve the maximum you can."

In practice yesterday, it was a day of contrasting fortunes as Heidfeld and Kubica finished second and third quickest in the first session, but then a surprising 20th and 17th in the second.