How much fuel does turning the car on consume?

[omgwtfbyobbq]

I think mechanically injected diesels require less than gassers, but don't quote me on it.

Originally Posted by skale7

Turning it back on in an auto is a serious PITA, so unless you can time the lights perfectly, you could just blow a green light trying to turn it on.

That's odd. I can usually turn on and get in gear in my auto Camry in about a second and a half, and if I time it right by watching the other lights, it's the same as just sitting there w/ my foot on the brake. Is something wrong w/ your starting system or transmission?

[GasSavers_Ryland]

if you search the forum, someone did a test to find out how much fuel it takes to let a diesel idle, and it's not much, and at least on diesels with mecanical fuel pumps, unless you are holding your foot down on the accelerator pedal as you crank the engine over, it should be injecting the same amount of fuel in on each rotation as it gets when it's idling.

the type of starting of your engine that I see that really gulps the gas is cold starts, that is why doing alot of short trips is bad for gas mileage, but if your engine is only turned off for a minute or two then a few seconds after the engine is started it should be running as lean as it was befor it was turned off.

we have really quick cyling stop lights in my little town, but I just came from minneapolis, and sat at stop lights for a minute or more each, much longer then I was used to.

[GasSavers_veloman]

Yes, 0mpg sucks, but at idle speed, your engine is barely using any gas, so in effect, that 0 mpg time is 'weighted' very litely.

To me, it just seems like the wear you would be putting on your car is not worth it to keep turning it on and off throughout your commute, to save a couple pennies of gas. I imagine it must take a couple seconds of sitting at a green light to turn the car back on? It must piss off the poeple behind you and cause more traffic in a sense. The only time I would see it practical to turn off the engine is on a long downhill where you won't need to slow down.

IDK, IMO, EOC just doesn't make a lot of sense to me. What happens when you guys hit an extra red light, effectively negating any savings? I found it out to be not worth the stress to be THAT anal about gas mileage. I drive efficiently and smooth, it's enough for me.

If it works out good for you, that's all that matter.

[skewbe]

I don't think you are ready for a serious mpg journey yet velo. There is so much doubt in you and and you have not yet seen the bigger picture, it would seem.

[psyshack]

Its all the little pixels that add up to the big picture. Some just cant see the forest because of the trees....

Have fun

psy

[Fourthbean]

I have my engine shut off at stoplights, and I am usually the first to start moving away when it turns green. Makes a difference when you are actually paying attention to the light.

Of course my engine is in pretty good tune so it just requires a flick of the starter and I just need to let out the clutch as I would already have it in first gear by then.

[MetroMPG]

Originally Posted by veloman

Yes, 0mpg sucks, but at idle speed, your engine is barely using any gas, so in effect, that 0 mpg time is 'weighted' very litely.

Don't tell that to the auto manufacturers who are rushing to implement automatic engine start/stop systems. They routinely claim fuel savings of between 5-10% in city driving for this feature.

To me, it just seems like the wear you would be putting on your car is not worth it to keep turning it on and off throughout your commute.

If I were still driving the fleet of Rabbits I owned in high school/university, I'd agree with you (they seemed to eat starter motors). But when was the last time you heard of someone replacing a starter in a car built in the last 15 years?

I imagine it must take a couple seconds of sitting at a green light to turn the car back on? It must piss off the poeple behind you

I imagine the people doing this are paying far more attention to the traffic situation than this, and are aware well in advance WHEN their light is about to switch back to green. So their cars are already runnning and ready to go when the light changes, making this technique undetectable to the people behind them.

I found it out to be not worth the stress to be THAT anal about gas mileage.

Everyone's different. I don't find it stressful at all. The only thing that might stress me is if the car wouldn't reliably start immediately.

I would never recommend anyone using a technique that they're not comfortable with.

I drive efficiently and smooth, it's enough for me.

That's better than the majority of drivers out there.

[Telco]

Three things on this .

One, when the fuel injectors are being repressurized, they are not leaking fuel. If they are, then they are faulty and need to be replaced.

Two, the manufacturer thinking on the start/stop at stoplights is through engine control. These systems won't use the starter to restart the engine, the computer keeps track of the crank location and will fire whatever cylinder is set at TDC on the compression cycle. The idea here is to let the engine start itself. No idea how long the car can sit before it has to be restarted manually. Eventually the manufacturers hope to do away with the starter altogether and just use engine firing to get the car started, but I seriously doubt they will ever get it to work as there are instances where all cylinders are positioned to where they would not be able to fire one with enough force to turn the engine over.

Three, the statement on it taking 1 minute's worth of idling fuel is not made up, just outdated. This came from the EPA in the 70s, when the world ran V8s with carbs. It did take a minute's worth of idling fuel to start the average car back then. Usually starting the car meant pumping the gas a couple of times, which shot extra fuel into the engine when the power pump was activated.

[lunarhighway]

i'm building a setup with 2 buttons that will enable me to start and stop the engine very easy, it should become opperational any day now (i just need to connect all the wires to the cars existing system), although i've gotten accustomed to use the key for now.
generally i turn of the engine at every redlight and closed railway crossings... it has become the same kind of routine as shifting gears although the key is not located very ergonomically wich is why i'm building the buttons.

some car makers have already experimented or even produced cars that would shut down the engine when the car was not moveing as early as the 80's and i believe mercedes is planning to reintroduce the system within a few years,...

also i stated to notice how comfortable the total silence and lack of vibrations in the car can be. it makes for less frustrating stop!

[GeekGuyAndy]

I would agree with MetroMPG on that. Everyone tells me I'm going to kill the starter. Lets see, I started hypermiling at 185,000 miles... if my starter goes, it's not going to be from hypermiling.