a buddy of mine left his dodge dakota idling while he went in the store for like 15 mins, i asked him why didnt he turn his car off and he said that it wastes more gas if you do that, is that true?

i have a dodge durango, my question is how many minutes can i waste idling before it wastes as much as if i were to turn my car off and walk in a store for a short period... that was kind of hard to explain

 

I think he is right on if his truck was carberated, i don't think he is right being fuel injected. good question. there is alot of room for debate on this subject, i think it may come down to personal prefernce,outside temperatures, etc. i can't answer the timeline when it becomes a waste of gas to being efficient for idling time.

 

Supposedly if you have to idle for more than as little as 20 seconds
it is more fuel efficient to turn the engine off,
which is similar to how some of the "light" hybrids do
like the Silverado pickup and Saturn Vue

 

i wouldnt let it idle for any more than like 2 minutes.... it's just waisting gas... with EFI you don't use much fuel on startup...

 

well i have fuel injectors so anything less then 2 minutes i should turn it off??

 

I would just recommend not to let the Durango idle for any reasonable length of time if you are not troubleshooting or letting the engine warmup to save gas. Also, cut down on emissions.

Example, if I am at a drive thru, I only idle if the line is moving quick, if not, I just start/stop the engine. The only bad thing about this is wearing out the starterfaster if I have to use it frequently.

 

ok cool. since were talkin about saving gas how much gas is really used when you turn your A/C on, a friend of mine said that keeping your a/c on doesnt waste any gas at all, but then i have another friend saying it only wastes gas when its on high and if its low it doesnt, i dont beleave them cuz they dont no nothin, but i still make my self suffer not putting the a/c on just to try to save some gas... i live in florida it is 85 degrees right now so imagine summer time

 

http://www.edmunds.com/advice/fuelec...2/article.html

has a section where they test out the effect of Air Conditioning
also one on use of cruise control

 

My "opinion" on the mpg issues is if your worried about gas consumption on start up, as well pricesof fuel you def have the wrong vehicle

 

SWAB:

If you search far and wide, you will get answers on both sides of the fence. Today's fuel injected motors are more efficient all around, and do not (should not) suffer from the warming up issues that their carburated counterparts of past decades did.

As a benchmark, the 4.6L V8 in the Crown Victoria (police version) consumes around .5 gallon an hour at idle. This number can vary a little depending on how much electrical load is on the alternator, etc.

For me, I tend to shut off my D if it will sit longer than a couple of minutes unless it is really hot or cold out.

Our family budget spent $4k on gas between my D and the wifes GCV in 2007. In the big picture that is probably not too bad, but it sure looks like a big number when you think about just filling your car up.

Don