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Old 27th February 2007, 10:25   #1
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Default Learning to drive: When does a car stall ?

When and why does a car stalls ? In the last two days i have managed to stall my car twice while (learning) driving. As per my instructor

1. I was in the first gear and i de-pressed the clutch without pressing accelerator and that too a little fast (I thought it was exactly the way I was doing earlier too !)

2. I was on the main road in 3rd gear and I pressed the brakes. According to my instructor, I didnt press the clutch before braking and that is why the car stalled.

Are these correct and why else would the car stall ?

Kalpesh
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Old 27th February 2007, 12:23   #2
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In short, a car stalls when the power required to move it is more than what the engine can provide in a particular gear / speed combination. The two situations you pointed out are examples of this. Others I can think of:

Starting up a steep slope, starting with the AC on, towing, driving with the handbrake engaged etc.
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Old 27th February 2007, 12:48   #3
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You don't exactly press the clutch while breaking all the time, u do that only when its necessary. And its not the right thing to do while cornering as it throws the car off balance
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Old 27th February 2007, 12:48   #4
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when you brake, as the car slows down to a halt, always depress the clutch to prevent the car from stalling.
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Old 27th February 2007, 14:32   #5
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Quote:
a car stalls when the power required to move it is more than what the engine can provide in a particular gear / speed combination.
This is the real reason.

Every engine has an idling RPM. In most cars it is within 800-1200 RPM. If you have a rev counter in your car, just make sure you don't go down that RPM while clutch is not pressed.
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Old 27th February 2007, 15:55   #6
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Obviously one cannot be peering into the tacho to see if it is time to hold the clutch while they are braking. It is the feel of the thing more than anything else. if you feel the car is going to stall, depress the clutch.
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Old 27th February 2007, 17:11   #7
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Quote:
Originally Posted by sbasak View Post
Every engine has an idling RPM. In most cars it is within 800-1200 RPM. If you have a rev counter in your car, just make sure you don't go down that RPM while clutch is not pressed.
Nice to see the technical stuff.

I do agree with what esteem_lover said.

Once you start driving for a while your foot will start pressing and de-pressing the clutch automatically based on your judgement of speed. Also learn about the usage of half-clutch, it's useful when u r moving bumper to bumper. It's very common here in Delhi.

Wishing u happy learning......
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Old 27th February 2007, 17:23   #8
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Quote:
Originally Posted by esteem_lover View Post
Obviously one cannot be peering into the tacho to see if it is time to hold the clutch while they are braking. It is the feel of the thing more than anything else.
- After stalling - that is when I peer at the tacho to confirm that the car has indeed stalled!
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Old 5th March 2007, 11:14   #9
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Originally Posted by mfb View Post
Also learn about the usage of half-clutch, it's useful when u r moving bumper to bumper.
Someone care to explain this ?
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Old 5th March 2007, 12:24   #10
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Usage of half-clutch (keeping the car stationary on a slope by using the clutch and accelerator) is NOT RECOMENDED as it leads to excessive clutch wear. Use the parking brake instead!
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Old 5th March 2007, 12:53   #11
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Are you learning on Your new car or On the Driving school car, There will be a difference in the way the clutch will behave, as a driving school car will require more effort and will already have the hell beaten out of it..!

Good luck with your classes..!
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Old 5th March 2007, 14:05   #12
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^^ Driving school car which has a ****ty clutch (according to my instructor who has 40 yrs of exp of driving !). It makes noise when i shift between 1 and 2, does not depress properly and the car itself is pretty old.

But after starting to depress clutch whenever the car is running slower than the gear that I am in (based on my estimation) - the car has stopped stalling. So maybe I am doing something right at last !
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Old 6th March 2007, 23:24   #13
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Quote:
Originally Posted by ajitkommini View Post
Usage of half-clutch (keeping the car stationary on a slope by using the clutch and accelerator) is NOT RECOMENDED as it leads to excessive clutch wear. Use the parking brake instead!
Hi ajitkommini,

I completely agree with you that one should not use half-clutch when drving on a up-hill slope and rather use the handbrake or parkingbrake judiciously.

When I mentioned about half-clutch in my earlier statement, I meant when one is driving bumper to bumper in an utterly slow-moving traffic on a plain road.

I do agree that it definitely leads to excessive clutch wear but that's the way you have to drive in case of heavy traffic which is very frequent in a city like Delhi.

I hope I have been able to put my point across.

Cheers,
MFB
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