What Should Be First Step To Start Car In Winters?

[Neil.Bhujbal]

This is absolutely same as written in Manual. They have mentioned that you can move the car immediatley, but it takes sometime to reach to its performance.
This is the reason, every manual suggest avoid driving a car for short duration in heavy traffic.

This "sometime" you are talking about is covered by the time you get on road.
Taking reverse,driving slowly through your colony/society.So by the time you reach on roads your engine is already heated up.

And which manual says to avoid driving the car for short duration in heavy traffic ? And why ?

This is correct, but it takes 3-5 mins. in morning for your engine to give performance.

The idea is the engine needs heat-up in morning, but driving slowly gives better heat than start and idling.

Same here,by the time you get onto the road the engine is pretty much heated up.

 

[RSM]

This "sometime" you are talking about is covered by the time you get on road.
Taking reverse,driving slowly through your colony/society.So by the time you reach on roads your engine is already heated up.

Same here,by the time you get onto the road the engine is pretty much heated up.

No, this sometime, is more than that. Around 3-5 mins.

 

[Akash]

I think we have had a lot of technicalities over this issue and i would appreciate if you people convey it in a precise,simpler and respectable way so that others can understand it well.

 

[350Z]

Thread Cleaned.

Every one here is requested to please keep their tempers in check. Discussions are good as long as they remain healthy and to the point. Remember, Your argument should be with posts NOT the Poster and the use of de-faming words is not at all tolerated in The Automotive India.

I would highly advise members to again go through the General Guidelines and maintain the decorum of this community. Further such arguments may lead to the issuance of Infractions/Bans.

Thank You For the Co-operation.

Drive Safe,
350Z

 

[Neil.Bhujbal]

My take on few things quoted in this topic -

1) There is no need to press the accelerator pedal 3-times before starting a carb car.
2) When you start your engine you don't have to wait for it to warm up & then move the car.
You can move as soon as the car starts.(applied to both carb & mpfi cars)
3) Pleas don't hurt you engine by keeping the choke open for 5-10 min's.
The choke is provided just to start the car.As soon as the car starts,just revv it and push down the choke.
Never use the choke for more than 1 or max to max 2 min's.It causes more flow of petrol,nothing else.
4) There is no need to press down the choke & pull it up again if the car does not start in first crank.Let the choke remain pulled & crank the engine again.
5) Car's manual which say - " You can move the car as soon as it starts " cant be called wrong.

If there are any owner's manuals or Wikipedia's going against the above points please let me know.

 

[Auto Hub India]

Accelerator pump

The greater inertia of liquid gasoline, compared to air, means that if the throttle is suddenly opened, the airflow will increase more rapidly than the fuel flow, causing a temporary "lean" condition which causes the engine to "stumble" under acceleration (the opposite of what is normally intended when the throttle is opened). This is remedied by the use of a small mechanical pump, usually either a plunger or diaphragm type actuated by the throttle linkage, which propels a small amount of gasoline through a jet, wherefrom it is injected into the carburetor throat. This extra shot of fuel counteracts the transient lean condition on throttle tip-in. Most accelerator pumps are adjustable for volume and/or duration by some means. Eventually the seals around the moving parts of the pump wear such that pump output is reduced; this reduction of the accelerator pump shot causes stumbling under acceleration until the seals on the pump are renewed.
The accelerator pump is also used to prime the engine with fuel prior to a cold start. Excessive priming, like an improperly-adjusted choke, can cause flooding. This is when too much fuel and not enough air are present to support combustion. For this reason, some carburetors are equipped with an unloader mechanism: The accelerator is held at wide open throttle while the engine is cranked, the unloader holds the choke open and admits extra air, and eventually the excess fuel is cleared out and the engine starts.





Choke

When the engine is cold, fuel vaporizes less readily and tends to condense on the walls of the intake manifold, starving the cylinders of fuel and making the engine difficult to start; thus, a richer mixture (more fuel to air) is required to start and run the engine until it warms up. A richer mixture is also easier to ignite.
To provide the extra fuel, a choke is typically used; this is a device that restricts the flow of air at the entrance to the carburetor, before the venturi. With this restriction in place, extra vacuum is developed in the carburetor barrel, which pulls extra fuel through the main metering system to supplement the fuel being pulled from the idle and off-idle circuits. This provides the rich mixture required to sustain operation at low engine temperatures.
In addition, the choke is connected to a cam (the fast idle cam) or other such device which prevents the throttle plate from closing fully while the choke is in operation. This causes the engine to idle at a higher speed. Fast idle serves as a way to help the engine warm up quickly, and give a more stable idle while cold by increasing airflow throughout the intake system which helps to better atomize the cold fuel.
In many carbureted cars, the choke is controlled by a cable connected to a pull-knob on the dashboard operated by the driver. In some carbureted cars it is automatically controlled by a thermostat employing a bimetallic spring, which is exposed to engine heat, or to an electric heating element. This heat may be transferred to the choke thermostat via simple convection, via engine coolant, or via air heated by the exhaust. More recent designs use the engine heat only indirectly: A sensor detects engine heat and varies electrical current to a small heating element, which acts upon the bimetallic spring to control its tension, thereby controlling the choke. A choke unloader is a linkage arrangement that forces the choke open against its spring when the vehicle's accelerator is moved to the end of its travel. This provision allows a "flooded" engine to be cleared out so that it will start.
Some carburetors do not have a choke but instead use a mixture enrichment circuit, or enrichener. Typically used on small engines, notably motorcycles, enricheners work by opening a secondary fuel circuit below the throttle valves. This circuit works exactly like the idle circuit, and when engaged it simply supplies extra fuel when the throttle is closed.
Classic British motorcycles, with side-draft slide throttle carburetors, used another type of "cold start device", called a "tickler". This is simply a spring-loaded rod that, when depressed, manually pushes the float down and allows excess fuel to fill the float bowl and flood the intake tract. If the "tickler" is held down too long it also floods the outside of the carburetor and the crankcase below, and is therefore a fire hazard.

Courtesy: Wikipedia

I would like to highlight some points from the above article:-

1. The accelerator pump is also used to prime the engine with fuel prior to a cold start. Excessive priming, like an improperly-adjusted choke, can cause flooding. This is when too much fuel and not enough air are present to support combustion. For this reason, some carburetors are equipped with an unloader mechanism: The accelerator is held at wide open throttle while the engine is cranked, the unloader holds the choke open and admits extra air, and eventually the excess fuel is cleared out and the engine starts.

The above extract shows that the accelerator pump which is connected to the accelerator pedal,is used to "prime" the engine prior to cold start.That means if we press the accelerator 3-times prior to cranking in the cold morning during a cold start, it helps in easier start of the carb engine.

If it is done more than 3-times it may lead to excessive flow of the fuel resulting in "flooding" which means that too much fuel is present in the engine and not sufficient air is there which can support the combustion to occur, that means the engine will not start on cranking.In the same way when choke is applied even between two successive cranks,it continuously draws fuel(as we know it is its function to flow extra fuel during cold start) and that will deffinitely help in "flooding" and result into non-occurance of the combustion.So choke should be released between 2 successive cranks.


2. choke is connected to a cam (the fast idle cam) or other such device which prevents the throttle plate from closing fully while the choke is in operation. This causes the engine to idle at a higher speed. Fast idle serves as a way to help the engine warm up quickly, and give a more stable idle while cold by increasing airflow throughout the intake system which helps to better atomize the cold fuel.


We can see in the above extract that choke causes the engine to idle at higher speed and serves as a way to help the engine warm up quickly.So if the choke is released as soon as the engine is started after a cold start then what is the need of the above mentioned function of the choke?It is meant for both--hassle-free cold start and fast and smooth warming up of the engine so that it reaches the optimum temperature for its best performance.

And so unless your engine have achieved the optimum temperature you cant release the choke, and this duration of time varies with the external environment temperature,which is highest in colder places in winter.

You just cant move your vehicle as soon as it get started as the engine wont give its best performance if it does not reach its optimum temperature, and the acceleration will feel sluggish.Its similar in mpfi and carb engines may be a bit more or less.

These are the best practices people can do.But its not mandatory, what ever users feel comfortable as per their views and thought, they are free to practice.

 

[Neil.Bhujbal]

1)

1.The accelerator pump is also used to prime the engine with fuel prior to a cold start. Excessive priming, like an improperly-adjusted choke, can cause flooding. This is when too much fuel and not enough air are present to support combustion. For this reason, some carburetors are equipped with an unloader mechanism: The accelerator is held at wide open throttle while the engine is cranked, the unloader holds the choke open and admits extra air, and eventually the excess fuel is cleared out and the engine starts.

Kindly not the above accelerator pump is a small pump surrounded by fuel & used only when you press the accelerator suddenly.
Moreover the above lines from Wikipedia no where tell to press the accelerator 3 times before starting an engine nor do they tell pressing the accelerator more than 3 times causes flooding.
All they say is to press the accelerator & then start the engine. That's a common practice in a carb car.(depending on the carb tuning)

Below is the explanation you have given -

The above extract shows that the accelerator pump which is connected to the accelerator pedal,is used to "prime" the engine prior to cold start.That means if we press the accelerator 3-times prior to cranking in the cold morning during a cold start, it helps in easier start of the carb engine.

If it is done more than 3-times it may lead to excessive flow of the fuel resulting in "flooding" which means that too much fuel is present in the engine and not sufficient air is there which can support the combustion to occur, that means the engine will not start on cranking.In the same way when choke is applied even between two successive cranks,it continuously draws fuel(as we know it is its function to flow extra fuel during cold start) and that will deffinitely help in "flooding" and result into non-occurance of the combustion.So choke should be released between 2 successive cranks.

2)

2.choke is connected to a (the fast idle cam) or other such device which prevents the throttle plate from closing fully while the choke is in operation. This causes the engine to idle at a higher speed. Fast idle serves as a way to help the engine warm up quickly, and give a more stable idle while cold by increasing airflow throughout the intake system which helps to better atomize the cold fuel.

When the engine is cold, fuel vaporizes less readily and tends to condense on the walls of the intake manifold, starving the cylinders of fuel and making the engine difficult to start; thus, a richer mixture (more fuel to air) is required to start and run the engine until it warms up. A richer mixture is also easier to ignite.
The source of above is wiki.
The very first lines in the choke section & it says the choke is used to start & run the engine & run the engine till it warms up.Mind you this warm up is not for 5,8-10 mins,its only for a min till the engine heats a little & the further temp rising can be done without the choke too.
(just start moving your car)
Keeping the choke ON till the engine warms up complete actually is running on a RICH MIXTURE. This rich mixture helps in keeping the engine temp down in certain cases.
So the choke (RICH RUNNING) should be only till the engine starts.

Below is the explanation you have given -

We can see in the above extract that choke causes the engine to idle at higher speed and serves as a way to help the engine warm up quickly.So if the choke is released as soon as the engine is started after a cold start then what is the need of the above mentioned function of the choke?It is meant for both--hassle-free cold start and fast and smooth warming up of the engine so that it reaches the optimum temperature for its best performance every morning when we start the car.

3)

You just cant move your vehicle as soon as it get started as the engine wont give its best performance if it does not reach its optimum temperature, and the acceleration will feel sluggish.Its similar in mpfi and carb engines may be a bit more or less.

We don't always look for optimum performance & efficient every morning we start our vehicles.So even if you are a second slower to any speed its not a big deal.

 

[Akash]

The above point is completely baseless. We don't always look for optimum performance & efficient every morning we start our vehicles.So even if you are a second slower to any speed its not a big deal.

No offenses meant.
The post by AHI explains the correct way for getting optimum performance by engine. Now it depends on the driver what he wants from the car. Some just move on (because of hurry to office or any other important thing), others remain patient enough to give their engines idling time for better performance as you suggested.

Now if you are not looking for performance during morning hours then its your wish(and other who are in hurry for something important like office meetings) dont you think. Then how is baseless. Please take this post in a healthy way.

 

[RSM]

The post by AHI explains the correct way for getting optimum performance by engine. Now it depends on the driver what he wants from the car. Some just move on (because of hurry to office or any other important thing), others remain patient enough to give their engines idling time for better performance as you suggested.

Akash, actually if you start the vehicle and move slowly, the engine heats-up more quickly than idling. And the performance comes quicker than you idle for sometime and move.
So even its good to idle for sometime, but starting immediatly also doesn't have any issue.

 

[Neil.Bhujbal]

No offenses meant.
The post by AHI explains the correct way for getting optimum performance by engine. Now it depends on the driver what he wants from the car. Some just move on (because of hurry to office or any other important thing), others remain patient enough to give their engines idling time for better performance as you suggested.

Now if you are not looking for performance during morning hours then its your wish(and other who are in hurry for something important like office meetings) dont you think. Then how is baseless. Please take this post in a healthy way.

I would still call it baseless.

Reason :- There is no major performance drop in the morning.The difference is in seconds,like 2 or 3 seconds late to achieve certain speed.

Now don't tell me to over come just those 2 seconds you will idle your car for freaking 5 mins.
(That even wastes petrol)

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If you own performance cars like the Evolutions or something they are different.
They don't go above 4-5K RPM unless they are heated up properly (1km or so).
This is to prevent engine from getting damaged. So if it was a similar case in our car's the manufacturers would have definitely mentioned it in the Manual's. (Like they have mentioned in the turbo cars).

 

[Akash]

Akash, actually if you start the vehicle and move slowly, the engine heats-up more quickly than idling. And the performance comes quicker than you idle for sometime and move.So even its good to idle for sometime, but starting immediatly also doesn't have any issue.

Thats what i am trying to say. That both the ways its good. I am not staying that you IDLE for sometime compulsarily.

@ALL- Then what is the concept of IDLING?

 

[Neil.Bhujbal]

@ALL- Then what is the concept of IDLING?

The concept of idling - It is the speed at which the otto cycle is performed without the help of any other external source.

The starter helps in starting the otto cycle.

(otto cycle are the 4 strokes of an engine,supporting each other & keep the engine running with the help of an flywheel)

 

[Akash]

By concept i mean is it not required at all?

 

[stayinalive]

well in case of a carburated engine, you need to start your vehicle with the help of choke for around 15 to 20 secs, and then let it idle with the choke off for another 15 to 20 secs. use min amount of accelerator if there is no starting problem with your vehicle. 1 to 2 mins. is enough for the circulation of oil inside the engine.

 

[Neil.Bhujbal]

By concept i mean is it not required at all?

It is required. It is required to set otto cycle in motion. And then the speed of this cycel is controlled by us (accelerator).It is for our comfort so that we take off our foot from the accelerator & the car still keeps on running (idling) at minimum speed.
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There are certain tech's being developed which allow to stop idling after certain drop in RPM. Its not out in market yet i guess,had read about it long time ago.
This tech is used in hybrid vehicles too.