Page 1 of 2 12 LastLast
Results 1 to 13 of 15
  1. #1
    Join Date
    Feb 2004
    Location
    Midwest
    Posts
    9,932

    Idling gasoline consumption question

    About how much gas does a Chevy van with a 350 V8 engine burn per minute or hour while it's idling?

    (Assuming it's warmed up, A/C not on, and it's not real hot or cold outside)

  2. #2
    Join Date
    Feb 2008
    Location
    Waffleville
    Posts
    10,339
    i worked for a co that had gps and would call you into the office if your "idle time" was high. rediculous if you ask me. it is cheaper to leave it running than to turn it off and then back on 5 or even 15 minutes later. EFI engines run very efficiently, except when they are started. when the engine is started and when it is below normal operating tempurature the EFI dumps a lot of fuel into the engine, completely disregarding the O2 sensors. when the engine is warm and has been running for certain amount of time the EFI reads the O2 sensers and continually adjust for proper air fuel ratio's if your into cars, look up closed loop, and open loop EFI operations
    If Guns Kill People, Do Pencils Misspell Words?

    http://www.youtube.com/watch?v=An2a1...eature=related

    Before we work on artificial intelligence why don't we do something about natural stupidity?

  3. #3
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,750
    About a gallon an hour. Would be my guess.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  4. #4
    Join Date
    May 2004
    Location
    Rapid City, SD
    Posts
    7,414
    I know this is apples to oranges, but my truck (7.3 liter diesel) burns around a quart an hour idling (at idling rpm, not sped up)... not a great thing to do for a long time because of wet stacking, but anyway.

    I'd venture to bet, on a newer van, that's warmed up and not running anything like A/C, a half gallon would last an hour.

    My theory on not shutting my truck off for quick stops is this... #1, things wear out every time they are shut off and on (switches, starters, motors, etc). #2, it's only a few minutes.

    I wouldn't likely leave my van or truck run if I'll be in some place much more than 10 or 15 minutes though unless it's really hot or cold out.

    And, as a rough calculation... my van normally gets 280-300 miles per tank (I try to fill up around 1/4 of a tank or less). In the winter, starting it 10-15 minutes early, and leaving it run quite often while I'm in working, I'd go down to 220-240 miles per tank. Not huge... but when I climb off a roof and it's 0 deg out, I better be able to go warm up in my van.
    "If you call that hard work, a koala’s life would look heroic."

  5. #5
    John Culpepper's Avatar
    John Culpepper is offline CHANGE YOUR EMAIL ADDRESS Professional Member*
    Join Date
    Oct 2007
    Location
    Austin Texas
    Posts
    1,776
    Here in Austin Tx. there is an ordinance for service vehicles (usually diesel and usually semi trucks) that they cannot sit and idle for more than five minutes.
    Nemo me impune lacessit.

    How much blood do I have to bathe in to get clean?

    Don't look down on anyone unless you're helping them up.

  6. #6
    Join Date
    Mar 2006
    Location
    OK
    Posts
    2,144
    The hyper-mileage guys shut theirs down any chance they get, coasting downhill, stoplights etc. It's hard to argue with people getting 50MPG from cars that AREN'T hybrids.
    Never knock on Death's door. Ring the bell and run, he hates that.

    Views expressed here are my own and not neccessarily those of any company I am affiliated with.

  7. #7
    Join Date
    Mar 2005
    Posts
    997
    I don't know were I have heard this and don't have any info to prove it but I had heard if you are idling for more than 30 seconds it is cheaper to turn the car off.

  8. #8
    Join Date
    Sep 2002
    Location
    Virginia
    Posts
    3,082
    Quote Originally Posted by beachtech View Post
    it is cheaper to leave it running than to turn it off and then back on 5 or even 15 minutes later.
    not exactly true on gasoline engines nowadays

    Quote Originally Posted by beachtech View Post
    EFI engines run very efficiently, except when they are started. when the engine is started and when it is below normal operating tempurature the EFI dumps a lot of fuel into the engine
    true ... to a point .... yes it enriches the fuel mix more when cold , but not to the point of blowing out black puffs of smoke out the tail pipe like on a carbed engine .



    Quote Originally Posted by beachtech View Post
    EFI completely disregards the O2 sensors when cold , and when the engine is warm and has been running for certain amount of time the EFI reads the O2 sensers and continually adjust for proper air fuel ratio's if your into cars, look up closed loop, and open loop EFI operations
    I did look into it .... back in 1989 at my Fuel injection class for my ASE certs

    And yes the computer does work just as you described . EFI doesn't send any output signals to anything until it reaches 150 degrees . It merely runs on a pre-set program . Although its not sending out info while cold - doesn't mean its disregarding anything ... its keeping an eye on the 02 and Egr , but its not going to make any adjustements until its in closed loop ( above 150 deg )

    But

    If you need to sit at idle for more than a minute on a EFI engine thats hot , you would save gas by turning it off .... its all physics . The average v-8 car has 20 lb injectors . Thats 20 lb of fuel an hour ( if they were wide open all of the time )

    In 15 minutes on a v-8 engine you would fill a quart glass with the gas its using even at the slowest rate of injector pulse gap which is about 0.9lb an hr x 8 injectors .

    In 15 minutes an engine thats Off wont use a drop .... and I can assure you it dont use a quart of gas to restart it

    Now .... dont get offended .... Im just telling you what I learned .

  9. #9
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,148
    Well, there ya have it. Right from an ASE guy.

    Don't leave 'em running.
    Perhaps you should have read the instructions before calling.

  10. #10
    Join Date
    Aug 2007
    Location
    NorthEast TN
    Posts
    70
    As a former ASE Master Tech ( impressive huh? - not really - ok ) I agree not to leave the engine running if stopped more than a few minutes. One thing, however, that I would recommend, especially for commercial applications, is using an additive like Slick 50, a synthetic oil, or at least a syn blend. I really like the Slick 50 as you can tell an immediate difference in cranking rpms. It reduces friction which increases engine life and fuel efficiency.

  11. #11
    Join Date
    Mar 2003
    Location
    Cincinnati
    Posts
    7,977
    A good friend of mine who works for a mainly residential company has gps on their vans. He told me the other day that the company has instituted a new policy of "fines". Anytime you go over 60 mph or if your van idles for more than 15 minutes you are charged $5 bucks per incident !! How about that.

  12. #12
    Join Date
    Jul 2004
    Location
    Victoria,Tx
    Posts
    6,680
    Quote Originally Posted by beenthere View Post
    About a gallon an hour. Would be my guess.
    I agree with beenthere.
    Ha, I am starting to see "no idling in school zones." I like the smell of burnt diesel. Matt good thread post. I like the way you think. You remind me of me.

  13. #13
    Join Date
    Jun 2004
    Location
    Howell, Michigan
    Posts
    16,173
    My new car has a mileage indicator on the dash. If I let it idle for 15 minutes, I loose at least 3 mpg.............up to .5 at a long redlight.

    Turn it off.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event