Stop/start cars left in gear.

[kazste]

Okay so was thinking about this the other day and while I suppose I could try it out really don't want too!
My car has this stop start technology so can sit at the lights with the clutch up and engine will stop.

I can however put the car into first without using the clutch and the engine will not start as no clutch used.

If the clutch was now depressed would the engine start and presumably drag first a little bit?

Second point is my car will also re start the engine should the car require it, for battery levels and such like, does this mean if the car was in first the car is smart enough to know and not restart or does it mean that a startled driver would go straight into the car in front?

Obviously the answer is, well don't leave it in first then, but if wonder how many do without thinking

[xRIEx]

kazste said:

Obviously the answer is, well don't leave it in first then, but if wonder how many do without thinking

This bit

kazste said:

I can however put the car into first without using the clutch and the engine will not start as no clutch used.

makes me think it's not really something 'many' will do without thinking. You must be actively (consciously) choosing to select first without the clutch. Driving a non-stop/start manual car for so many years has ingrained the 'clutch down, select gear' process to me that I never tried it with the stop/start cars I've had.

[adsvx220]

No!! If you engage 1st whilst the start/stop is doing its job at the lights it will not restart whilst in gear.

[GoTea]

Wait, the engine restarts of it's own accord?

Regarding slipping it into gear while in stop/start mode, I thought the engine doesnt restart until the clutch is fully depressed?

[xRIEx]

GoTea said:

Wait, the engine restarts of it's own accord?

Yep, Audis will restart if the engine is off too long, possibly to maintain oil or coolant temperatures, I dunno.

[Antony Moxey]

My XF restarts itself too. I guess it's to stop the battery going flat as everything that's on - radio, air on, lights etc - stay on when the engine cuts. Don't have the issue the OP has as mine's an automatic that stays in gear anyway.

[richs2891]

BMW will restart after a period of time as well, to stop the battery going flat ?
Also if the car has stopped via its top start and the car rolls forward or backwards it will restart the engine. (on a manual car obviously - cant do this with a auto !)

Edited by richs2891 on Sunday 27th July 10:16

[GoTea]

Never noticed it in my VW, but I rarely seem to be stuck in heavy traffic.

[miniman]

adsvx220 said:

No!! If you engage 1st whilst the start/stop is doing its job at the lights it will not restart whilst in gear.

Mine will

[Dodsy]

Surely you also have to have your foot on the brake for the stop/start to work so it wouldnt really matter. I know in the many different Jags I have used that you have to sit with your foot on the brake which I dislike as modern brake lights are like lasers and I could see the interior of the car behind being illuminated by them.

[CYMR0]

kazste said:

If the clutch was now depressed would the engine start and presumably drag first a little bit?

Depends. On a Mercedes E-Class - yes. On a Ford Focus, no. In the E-Class I'm often in first with the clutch depressed for a quicker getaway, which means that when I'm in a Focus I end up slowing myself down putting the car into neutral once I've worked out why it won't start...

It's rare for the Mercedes to restart itself but it won't start unless the clutch is depressed anyway.

[GoTea]

Would the auto hold feature prevent the car lunging forward if the engine restarts in-gear?

I can't see the benefit of putting it into first gear anyway while stuck in traffic, but it's an interesting point. If something can go wrong, it will.

[CYMR0]

GoTea said:

I can't see the benefit of putting it into first gear anyway while stuck in traffic

It means you can move away with just the clutch, without having to actually put it in gear first.

[smileymikey]

My Astra will start itself if you open the drivers door ( when the ignition is on obviously). I've never really understood this, unless the power draw from the interior light's going on trigger it?

[Superhoop]

The systems are a bit more savvy than you're giving it credit for - if you put in gear, the car would know it's in gear and therefore auto restart would be cancelled.

As for people questioning why they auto restart, it can be for any number of reasons; battery voltage, too great a difference between inside/outside temperature, PAS or EPAS required, brake vacuum too low, vehicle has started to roll on an incline... They will also cancel auto restart if: you put the car in gear, you open the driver's door etc..

The bigger question is, why would you put in gear in the first place?

[xRIEx]

Dodsy said:

Surely you also have to have your foot on the brake for the stop/start to work so it wouldnt really matter.

Only on an auto.

[strath44]

^ I take when re the merc you say your in 1st with the clutch depressed you mean you are in 1st and when you depress the clutch - otherwise if you have the clutch depressed the engine would still be running!?

Either way I wouldn't recommend this must be sore on the flywheel and starter.

[strath44]

^ I take when re the merc you say your in 1st with the clutch depressed you mean you are in 1st and when you depress the clutch - otherwise if you have the clutch depressed the engine would still be running!?

Either way I wouldn't recommend this must be sore on the flywheel and starter.

[Qwert1e]

Not stop-start, but I used to have a manual transmission car (Saab) with cruise control. If you moved the gear lever to neutral without using the clutch the engine would rev to the sky as the car's speed began to reduce!!

[kazste]

My car is a mini and a bmw, which I presume is roughly the same software, engine will restart either on its own depending on parameters or with the clutch depressed. It does not seem to drag if in first and then clutch pressed so suspect it needs to be fully disengaged was just wondering if anyone has had it start in gear.

A post earlier stating the car will know its in gear made me remember that a friends Audi will show you what gear you are in so presume that this would be the case. This then leads me to think on a hot day in a traffic jam you could leave the car in first to stop it restarting itself. This would mean you keep air on running as opposed to turning the engine off properly.

This is of course ignoring the whole running out your battery issue.