Welcome to second practice for the Malaysian Grand Prix, and welcome back if you were with us for FP1. It was quite a session, with numerous odd failures seeing cars off track. There could be more of the same when the next session gets started in just over 15 minutes.

We had a dry first practice session this morning, but the heavy rain that hits Sepang usually comes between 3pm and 4pm local time. So there could be an extra element in the mix.

Renault are reporting that its problems this morning were caused by upright failures and not the brakes. Similarly, d'Ambrosio had a wishbone failure when he went off under braking for the final corner.

Brake issues would have been a surprise, as, despite all the big braking zones, there are plenty of straights between each one that give the brakes time to cool. We'll have to see if any more teams have problems during the next session.

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It's still dry in Malaysia, with the track temperature at 49 degrees - much higher than the Pirelli tyres have experienced before.

Mark Webber was more than 1.5 seconds clear of Lewis Hamilton in FP1, but many late runs were scuppered by Jerome d'Ambrosio's incident.

The session gets underway with Paul di Resta sitting at the end of the pit lane and Jaime Alguersuari having to go around him.

Mark Webber carries out a practice start as he leaves the pit lane.

Jaime Alguersuari runs a bit wide through turns seven and eight. It's not the first time he's done that today, and both Lewis Hamilton and Fernando Alonso also had similar trouble.

Sergio Perez follows Algursuari over the line to top the timesheets early on with a 1:42.171.

Heikki Kovalainen is back in the Lotus this afternoon after Davide Valsecchi was at the wheel during the first session.

17 cars out on track as we see a busy start to the session.

Felipe Massa tops the timesheets ahead of Michael Schumacher who locked up going in to the final corner, but nobody has yet gone under 1:40s.

Lewis Hamilton puts in a quick time, making full use of the DRS and KERS to go 1.4 seconds quicker than anyone else so far.

Pastor Maldonado got through a lot of laps this morning, and we've just seen him sat in his car studying some more telemetery.

Some rather large marbles being picked off Lewis Hamilton's tyres in the McLaren garage.

Hamilton and Schumacher the only men under 1:40s so far.

Rubens Barrichello started a lap with the fastest sector time so far, but finished it over two seconds off the pace.

Adrian Sutil goes off at turn five after losing the back end, but travels safely across the grass and rejoins.

Mark Webber is on a heavy fuel run, and receives instructions to ease off through the fast change of direction of turns five and six to help preserve his tyres.

Webber now complaining about his rear tyres already going off. The track is very hot at the moment.

Ferrari say they have just completed runs on the experimental hard tyre, while Virgin say the suspension is "coming together nicely" on d'Ambrosio's car as they fix it following his failure this morning.

Nico Rosberg goes third fastest behind Hamilton and Schumacher. Mercedes was very busy in FP1 as it tries to find the right set-up for the car.

Maldonado goes quickest despite staying well off line on the back straight which will have seen him pick up a lot of marbles.

Only the three drivers that had issues in the first session - Heidfeld, Petrov and d'Ambrosio - have yet to set a time this afternoon.

Marco asks: "Do Mercedes run the McLaren KERS or do they have their own?"

McLaren, Mercedes and Force India all run the same system mated to the Mercedes engine. There might be some differences in packaging but the basics unit is the same.

Marco also wanted to know: "Are the Williams still running flywheel generated KERS or the same type as the other teams?"

Williams do produce a flywheel KERS but have never used it in F1. This season they have their own in-house battery system but haven't ruled out adapting the flywheel system for F1 in the future.

If you've got a question click on the link at the top of this window.

Karthikeyan gets in the way of Hamilton coming out of turn two. The HRT with a new front wing hasn't been near the pace so far today.

Jenson Button improves to third fastest, half a second off Hamilton's pace. Maldonado set the fastest time so far on the soft tyre.

Barrichello goes third fastest on the soft tyre, while Button improves just behind him.

Laurie Bowler asks: "How many sections on the track are designated DRS sections?"

During free practice the drivers can use the DRS whenever they choose. When it comes to the race there is only one section, which in Malaysia is the length of the pit straight, and the gap is measured from a point just before the previous corner.

Matt Henderson says: "Any idea if Red Bull are happy with KERS after practice 1 and using it for Practice 2? I would love to know if they've made a call about using it for the race yet."

Red Bull were running KERS in FP1 and it seemed to be reliable on Mark Webber's car. We've yet to see if they are using it again in FP2 but if the system works consistently for them then expect to see it on the car for the race - it's a very long run down to turn one here and Lewis Hamilton managed to hold off Mark Webber at the start using the system in Melbourne.

Petrov is wandering around his pit garage as he waits for his Renault to be fixed. The team have said "No running for LRGP at the moment as we try to fully understand our suspension issues from this morning. Best to be on the safe side."

Schumacher goes quickest by almost 0.9s with a run on the soft tyres, and Alguersuari goes second also on the softs.

Thong asks: "Why can't Vettel perform today? Any technical problem with his car?"

No real problem with his car, it's just the schedule that Red Bull are running. To prove the point Vettel is on a flyer now, and goes quickest by a whole second.

Webber follows his team-mate over the line and goes quicker still, the first man in to the 1:36s bracket.

Maldonado runs wide in to the gravel as he struggles to get the car turned in at turn eleven.

Oh dear, not a good day for HRT. Tonio Liuzzi has parked his car on the inside of turn nine with what looks like a mechanical failure.

Replays show Liuzzi running wide on the exit of turn six and having a big bump over the kerbs that seems to cut out the electronics.

And another man off the track, oddly Maldonado has put his car in to the tyre barrier on the way in to the pit lane after putting two wheels on the grass.

McLaren are working on the rear wing of Button's car after a DRS issue.

Vitaly Petrov is out on track and has just completed his first flying lap. He could be forgiven for being a bit unnerved after his mechanical failure earlier today.

Button is now out on the soft tyre and sets the fastest first sector time.

Button goes second fastest, losing a bit of time with a twitch under braking in to the final corner.

Force India reporting: "Paul happier with car after latest changes. High speed balance not too bad, 'just a little on understeer side'."

Karthikeyan does an improved lap but spent most of the time with smoke coming out the back of his car. He continues round though.

Very few laps from Lotus this afternoon, just nine between them. Tony Fernandes says it's due to a gearbox problem for Kovalainen and steering issues for Trulli.

Some great images of Liuzzi explaining the moment that he ran wide and his engine cut out, motioning with his hand that it stopped as the car landed.

Ray in Mildura, Australia, asks: "Why don't you have a column for times?"

As much as we would love to bring you times, as it stands FOM won't allow anyone to bring you live timing other than themselves.

Michael Schumacher runs wide after getting sideways through turn six, the back end stepping out on him and causing him to take a trip across the gravel.

Webber and Button the only two men under 1:37s at the moment, with just five thousandths of a second between them.

Nick Heidfeld is out on track too, and up in seventh place with a 1:38.570 after just 6 laps.

Timo Glock improves his time to a 1:40.8, putting hin ahead of both Lotus cars and Sutil at the moment.

Hamilton improves to a 1:37.010 on the soft tyre, just over a 0.1s slower than Webber and Button.

Craig Gunnis wants to know: "Did Red Bull use KERS on their fast laps?"

The honest answer Craig is we don't know. We weren't on board to see when the times were set. As soon as we find out we'll let you know.

Luthando gives his opinion on Williams, and in particular its KERS development:

"Williams always insisted on developing both types of the Hybrid system, but we all know that KERS is an expensive technology to develop, and Williams doesn't exactly have endless funds to do this. My belief is that Williams should have looked to get a Renault engine and KERS deal and shouldn't have penned the Cosworth deal in the first place. This way they could have developed their Flywheel system for commercial purposes as they are doing without the burden of simultaneously developing a battery alternative to run in F1, should their Flywheel alternative ever give potential advantages then they would have access to this first hand and hold an advantage which they would hold until others finally develop Flywheel systems of their own.

Mercedes and Ferrari have bottomless bank balances with which to fund KERS development, Williams has deviated from what made his team great in the first place (Innovation and Ingenuity - Just like The Lotus' of Colin Chapman)."

Sebastian Vettel does a lap over seven seconds off the pace as he does a heavy fuel run on the soft tyre, simulating the first stint of the grand prix.

Vinay is worried about Ferrari's pace: "As an Alonso fan, should it be a concern that the car might not be fast enough?"

While the Ferrari wasn't quick in Melbourne, don't judge them on practice today. Ferrari never show the full pace of its car on a Friday, and are likely to be more competitive later this weekend.

Moris in the Netherlands asks: "How can the teams set the cars up under dry circumstances for possible rain on Sunday?"

The teams can only really work with the conditions they've got Moris. They have standard wet setups ready but will just need to react to any rain that comes on Sunday. Some of the teams also got to run in very wet conditions during testing, so will have an idea of how to set the car up, and of course we've had plenty of rain in Malaysia before so they can draw on that experience.

On the track, most of the teams are now carrying out heavy fuel runs, leading to times well off the headline pace. Maldonado has got back out after his crash in the Williams though, so obviously didn't damage the car too heavily.

Michael Schumacher oddly lapping with his rain light on. Button does a 1:44.5 with heavy fuel, compared to a 1:44.7 from Webber.

Jerome d'Ambrosio will get back out for the last seven minutes, with Virgin saying: "Jerome climbs in. Rear wheels are on. Fitting the last shroud to the front brakes now. This has been a LOT of work..."

Hamilton also with high fuel, also does a 1:44.5 like his team-mate. Webber's last lap was a 1:44.4 and Vettel's a 1:44.6, so the McLaren's are competitive on this evidence.

Webber goes even quicker with a 1:43.8, which would suggest Red Bull have a bit more in reserve.

We have 18 cars out on track at the moment, trying to understand the tyres on high fuel loads.

Maldonado completes a lap having once again swept across the back straight and picked up more marbles on his tyres.

Button does consecutive times of 1:44.7, 1:45.9 and 1:46.9s, which could be down to traffic as it is now very busy on track, but could also be the tyres degrading.

Liuzzi is back out on track for HRT, as one of 19 cars lapping at the moment.

Nico Rosberg struggles to get his Mercedes slowed down in to turn one as his tyres go off.

The chequered flag falls with 20 cars out on track.

Webber's last lap is a 1:43.591, four tenths quicker than Vettel's time on heavy fuel.

Tonio Liuzzi one of the only men to improve on their lap time, doing a 1:43.991 to finish just over 7 seconds off the fastest time of the day.

All of the cars returning to the pits in safety car mode, having to follow a sector time read out on their steering wheels.

So the session ends with Webber quickest on a 1:36.876, just 0.005 seconds quicker than Button in second. Hamilton third 0.1s further back, and Vettel in fourth. Schumacher was best of the rest, but a second slower than Vettel.

At the back, Karthikeyan would be inside 107% if it was qualifying, with Liuzzi just outside having had limited running.

So that concludes Friday's practice sessions. Thanks for all your questions, be sure to join us again tomorrow for practice and qualifying ahead of Sunday's Malaysian Grand Prix.