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nieuweyork t1_je6ysie wrote

> pumped gas while the engine ran to save gas by keeping the car running 24 hours per day

How does this work? Why does it save gas to unnecessarily run the engine for ~2 minutes?


BradMarchandsNose t1_je74vlc wrote

Older carbureted engines would use a lot of fuel to start up, so there was a “5 minute rule.” If you were stopping for less than 5 minutes, it would use more gas than letting the car idle. I have no idea if this is true or not scientifically, but that was what people said. These days though, that’s not the case at all. They build cars now that stop the engine at a stoplight and start it back up again 10 seconds later because it’s more efficient with modern engines.


puppydogbryn t1_je73d1w wrote

It does save fuel to shut the engine off. You only waste fuel if you keep it off for like less than 15 seconds.