Saving gas


With gas approaching $9000/gal, I was looking for opinions on whether shutting the motor off at red lights is worth it. It may cause more wear to the starter or to the cylinder walls(since the oil drains down) than is worth a minute’s worth of gas, right?


[b]There’s no real advantage in shutting the engine off at stops in an effort to save gasoline. As matter of fact, restarting the engine may use more gasoline. This is because when an engine is restarted, during the cranking mode the injectors introduce a steady stream of gasoline to make sure the engine starts. It’s not until the engine starts and runs where the injectors pulse to introduce the gasoline.

Besides, shutting the engine off can be dangerous in the event a reason arises where you have to get out of the way in a hurry. And in some states, it’s illegal to turn the engine off while on public roads unless it’s an emergency or a mechanical failure.



Wow, I never knew that the injectors behaved that way. I guess it would only save gas if it was several minutes. However I do notice that the mail trucks shut off their motors at each mailbox, even for ~15 sec.


You may save a bit of gas turning off the engine at long waits, such as waiting for a passing train or when in a slow moving drive-up line. But you save nothing for waits of about a minute or less. Starting requires a heavy drain on the battery which must be replenished, and this can only be done by using more fuel.


Good thought. It does drain the battery pretty good. I’m actually amazed that the battery can quickly turn over a pressurized engine, as it is.


A handful of hybrids are DESIGNED to do this and over time it does save gas. But they use a completely different starting system. Most of todays (and yesterdays) starters are not designed to be used that often. They will fail quickly under constant use. The hybrids shut off and re-start seamlessly and automaticly with not input from the driver.

For long waits, over 4 minutes, yes, turn it off…


Thanks Caddyman, might be almost time to get one of those hybrids (even though they cost thousands more)


I have heard that some Europeans do this. In some circles, it is considered socially responsible conservation.

Frankly, the amount saved at traffic lights is negligible compared to what you can save simply by consolidating two trips into one.

If the price of gasoline ever reaches nine thousand dollars per gallon, we won’t have to worry about wasting it at traffic lights because we will never get out of the garage.