i do this alot. when i just catch the light and i know its going to be a good 3 or more mins i shut the car off to save gas. its best when im not first in line so i dont have to respond as quickly. im not sure how much gas im saving, i just get sick of knowing im going to be sitting there for a few minutes and i shut the car off to just 'give up'[V] anyone else?

i dont do this personally. i never saw the point of putting all the extra wear and tear on my starter and other parts just to save a few pennies on gas....

but if you want to, feel free.

couldn't that be dangerous? and don't you use up all the gas you just saved to start the car again?

not sure, just asking

I don't but I usually drop it in neutral for those exceptional long lights (even though I have an auto). Housecat, I think I remember reading somewhere that as far as gas consumption goes, starting it actually takes less than letting it sit and idle.

I try to avoid these situations altogether by speeding up to duck under the yellow if there is the faintest chance I might make it! Luckily a lot of people do it around here so I don't look like such a bad driver!

Originally posted by housecat4ever
couldn't that be dangerous? and don't you use up all the gas you just saved to start the car again?

Well I could be wrong, too, but this is what I've always been told as well. Obviously it's going to be a problem if something sudden and unexpected happens. But who am I to talk? I always shift into neutral at the red lights, and you're not supposed to do that for the very same reason - you're not ready in an emergency situation. [:I]

You'll use more gas starting it back up than idling for a couple of minutes.

thx guys [:)]

Originally posted by DidHeFocus?
You'll use more gas starting it back up than idling for a couple of minutes.

That's correct if you have a carburetor. For injection is better to turn it off if stopped over 1 minute.

that isn't correct for any car. You don't ever use any gas to restart a hot engine. It is primed and ready to run. You also will save a VERY insignificant amount of gas by shutting it off. You might save a gallon in ten years of driving. But your wearing your starter, and possibly your engine some because you have no oil pressure again on startup. I wouldn't do it, not worth it

where in NY are you from?

I always go neutral at lights.

If you turn off and restart your engine at every stoplight you will wear your engine out much sooner. The most wear on an engine is at startup- NO OIL PRESSURE- for a couple seconds.
You also wear out your battery and starter much sooner.
It also takes more fuel to start the car then to sit at idle. At idle there is no load and very little fuel used.
So save yourself an engine and keep it running!

Originally posted by ricekiller
You also wear out your battery and starter much sooner.

This is true. The job that I do on the weekends, I used to do seven days a week for about a year or so when I was in college. It's essentially a delivery job, with lots of stop and go driving and starting and shutting off the car. Back then I was driving my 86 MR2. Altogether, I've been working that job either part or full time for seven years, and about five or six of those were spent driving the MR2.

In that time the battery actually lasted pretty well, I think it only had to be replaced once. But the starter - wow. I think it got replaced four times if I remember correctly. I tried aftermarket and that starter lasted about six months. The Toyota ones were good for about a year and a half, and each one cost me over $300. To be fair though, the MR2's ancillary components like the starter and alternator are well-known for failing earlier than they should, presumably due to the high heat in that tiny little engine compartment.

Now, even though I don't like leaving my car running while I'm not in it, that's what I do. It's a lot cheaper than constantly replacing starter motors. I just leave it and run up to the door hoping no one jumps in and takes off while my back is to the car! [:D]

About the fuel thing - we need one of the smarty-pants engineers to find this thread and see if they can explain that. It would seem logical that it would take more fuel to start the combustion process than it would take to keep combustion happening, so to me it makes sense that starting the engine would use excess fuel compared to idling. [?]

It DOES take more fuel, even in injection vehicles, to start the car.

The difference is HIGHLY NEGLIGIBLE as to the amount of fuel you save. An idling 4 cyl uses a rediculously small amout of fuel.

Also, putting an auto in neutral at a stop light = bad and unnecessary. Putting a manual into neutral at a stoplight = good, your clutch will thank you.

The comment about oil pressure is probably the biggest reason to not turn the car off.

Some of the things people do to separate themselves from the other millions of car owners in the world is mind boggling.

Turning the engine off at a stop light? .... good lord