1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Gas consumption in deceleration

Discussion in 'Technical Chat' started by Warren Thompson, Aug 5, 2009.

  1. Warren Thompson

    Warren Thompson [OP] GeoTaco

    Joined:
    Jul 19, 2009
    Member:
    #19861
    Messages:
    263
    Gender:
    Male
    First Name:
    Warren
    Elko, Nevada
    Vehicle:
    '06 Tacoma DC TRD Sport RadRed
    I have always wondered. I have a Taco 4.0 6 cylinder and do much offroad. My question is this... when I use the engine compression stroke to decelerate going down hill (foot off gas pedal), is there gas being fed through the injectors into the cylinders?? Is fuel still being consumed in the engine? Does the computer know when compression is being used to slow the engine and shut off the gas flow?

    To me, it sure makes sense that gas flow to the injectors is shut off in deceleration, but is it???

    Thanks for any help.
     
  2. sriley727

    sriley727 Well-Known Member

    Joined:
    May 3, 2009
    Member:
    #16735
    Messages:
    148
    Gender:
    Male
    Aiken, SC
    Vehicle:
    08 Reg cab PreRunner SR5
    Bone stock
    For the first few seconds, there is still gas flow into the cylinders. Once the computer realizes the truck is coasting, it will shut off the fuel. Its very noticeable in a truck with a manual when the fuel shuts off because the truck will slow down faster but you may not even notice with an auto.
     
  3. chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Staff Member

    Joined:
    May 8, 2008
    Member:
    #6497
    Messages:
    103,449
    Gender:
    Male
    First Name:
    FlimFlubberJAM
    Tenoe, AZ
    Vehicle:
    2013 Rubicon Unlimited,
    4.10 gears, sliders, lots of buttons, and yellow flashing lights on the dash.
    Actually, its pretty noticable in the Autos also. :)
     
  4. scocar

    scocar Not one of the 10,000 Baja Edition Elite Guard

    Joined:
    Nov 11, 2009
    Member:
    #25814
    Messages:
    21,509
    Gender:
    Male
    First Name:
    Glitterdick
    In close proximity to an undisclosed location
    Vehicle:
    01 Xcab TRD 4x4 V6 Man. SR5
    OME 881s, Dakars, greasable shackles, Nitrocharger sports, extended exhaust hanger, BAMF BPV relocate, Wheeler's extended brake line, rear diff breather mod, swaybar removed, Pilot backup lights, Redline hood struts, 4Runner 5-stars, Hidden Hitch Class III, 7-pin marine-grade wiring
    Is this the case with 1st gen V6 manuals, too? My 93 22RE manual never did this, but I've been noticing something strange like this in my "new" 2001. It's like a two-phase deceleration when I let off the gas, more noticeable at lower speeds. It's buggin' me, makes me wonder. I just lubed the driveline (which made soem other clunking go away), so that isn't an issue.
     
  5. RelentlessTaco

    RelentlessTaco Custom Tacoma bumpers & more for your offroad toy Vendor

    Joined:
    Feb 17, 2008
    Member:
    #4772
    Messages:
    13,333
    Gender:
    Male
    First Name:
    Eric
    East side of the Sierras, NV
    Vehicle:
    07 SR5 4x4> 03 SR5 4x4 total> 14 Crewmax TRD
    Had tons on the Taco's.... new truck is stock for now
    yeah, it does as the other guys have said. my scangauge reading "9999" for gas mileage on deceleration proves it too. :)
     
  6. scocar

    scocar Not one of the 10,000 Baja Edition Elite Guard

    Joined:
    Nov 11, 2009
    Member:
    #25814
    Messages:
    21,509
    Gender:
    Male
    First Name:
    Glitterdick
    In close proximity to an undisclosed location
    Vehicle:
    01 Xcab TRD 4x4 V6 Man. SR5
    OME 881s, Dakars, greasable shackles, Nitrocharger sports, extended exhaust hanger, BAMF BPV relocate, Wheeler's extended brake line, rear diff breather mod, swaybar removed, Pilot backup lights, Redline hood struts, 4Runner 5-stars, Hidden Hitch Class III, 7-pin marine-grade wiring
    Huh. So just to be clear, I see you have a 2nd gen, and this thread started regarding a 2nd gen 4.0, but you know this to be true of the 1st gen 3.4 V6 5VZE? Did you have a scanguage in a 1st gen at some point, or see someone else's do this?:confused:

    Just curious, because we are talking about different trucks and engines. I always appreciate demonstrable facts rather than hearsay or opinion on stuff like this, so I like your idea of being able to prove it with a scangauge (which obviously I don't have). This issue is kind of hard to search the threads for...

    Thanks for your input.:D
     
  7. RelentlessTaco

    RelentlessTaco Custom Tacoma bumpers & more for your offroad toy Vendor

    Joined:
    Feb 17, 2008
    Member:
    #4772
    Messages:
    13,333
    Gender:
    Male
    First Name:
    Eric
    East side of the Sierras, NV
    Vehicle:
    07 SR5 4x4> 03 SR5 4x4 total> 14 Crewmax TRD
    Had tons on the Taco's.... new truck is stock for now
    Well I was talking about a 2nd gen, but 2 guys I know have 1st gens, 1 w/ the 2.7 and one with the 3.4, that have scangauges. I try and see what theirs reads on decel next time im in their trucks.:cool:
     
  8. scocar

    scocar Not one of the 10,000 Baja Edition Elite Guard

    Joined:
    Nov 11, 2009
    Member:
    #25814
    Messages:
    21,509
    Gender:
    Male
    First Name:
    Glitterdick
    In close proximity to an undisclosed location
    Vehicle:
    01 Xcab TRD 4x4 V6 Man. SR5
    OME 881s, Dakars, greasable shackles, Nitrocharger sports, extended exhaust hanger, BAMF BPV relocate, Wheeler's extended brake line, rear diff breather mod, swaybar removed, Pilot backup lights, Redline hood struts, 4Runner 5-stars, Hidden Hitch Class III, 7-pin marine-grade wiring
    Dood, that would be awesome. Thanks.:thumbsup: I think half the confusion about techincal dicsussions on this site results from cross-generational vagueness and assumption. Just go check out the hubcentric lugcentric discussions....:goingcrazy:

    I'm sure lots of puzzled first genners without scangauges would appreciate the info.
     
To Top