Learning to drive: When does a car stall ?

kalpeshc · 27th February 2007, 10:25

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

ajitkommini · 27th February 2007, 12:23

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.

karthik247 · 27th February 2007, 12:48

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

esteem_lover · 27th February 2007, 12:48

when you brake, as the car slows down to a halt, always depress the clutch to prevent the car from stalling.

sbasak · 27th February 2007, 14:32

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.

esteem_lover · 27th February 2007, 15:55

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.

mfb · 27th February 2007, 17:11

Quote:

Originally Posted by sbasak

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......

johy · 27th February 2007, 17:23

Quote:

Originally Posted by esteem_lover

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!

kalpeshc · 5th March 2007, 11:14

Quote:

Originally Posted by mfb

Also learn about the usage of half-clutch, it's useful when u r moving bumper to bumper.

Someone care to explain this ?

ajitkommini · 5th March 2007, 12:24

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!

wolfinstein · 5th March 2007, 12:53

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..!

kalpeshc · 5th March 2007, 14:05

^^ 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 !

mfb · 6th March 2007, 23:24

Quote:

Originally Posted by ajitkommini

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

27th February 2007, 10:25	#1
kalpeshc BHPian Join Date: Dec 2006 Location: Mumbai Posts: 544 Thanked: 141 Times	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
	() Thanks

27th February 2007, 12:23	#2
ajitkommini BHPian Join Date: Sep 2006 Location: Bangalore Posts: 488 Thanked: 124 Times	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.
	() Thanks

27th February 2007, 12:48	#3
karthik247 Senior - BHPian Join Date: Feb 2005 Location: BLR, HYD Posts: 2,710 Thanked: 30 Times	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
	() Thanks

27th February 2007, 12:48	#4
esteem_lover Senior - BHPian Join Date: Jul 2006 Location: Madras/Py Posts: 7,556 Thanked: 513 Times View My Garage	when you brake, as the car slows down to a halt, always depress the clutch to prevent the car from stalling.
	() Thanks

27th February 2007, 15:55	#6
esteem_lover Senior - BHPian Join Date: Jul 2006 Location: Madras/Py Posts: 7,556 Thanked: 513 Times View My Garage	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.
	() Thanks

5th March 2007, 12:24	#10
ajitkommini BHPian Join Date: Sep 2006 Location: Bangalore Posts: 488 Thanked: 124 Times	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!
	() Thanks

5th March 2007, 12:53	#11
wolfinstein BHPian Join Date: Feb 2006 Location: New Delhi Posts: 994 Thanked: 20 Times	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..!
	() Thanks

5th March 2007, 14:05	#12
kalpeshc BHPian Join Date: Dec 2006 Location: Mumbai Posts: 544 Thanked: 141 Times	^^ 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 !
	() Thanks