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

Big time mpg drop...?

Discussion in '4 Cylinder' started by ttylerr, Aug 12, 2009.

  1. Aug 12, 2009 at 1:29 AM
    #1
    ttylerr

    ttylerr [OP] Well-Known Member

    Joined:
    Jun 1, 2009
    Member:
    #17913
    Messages:
    833
    Gender:
    Male
    First Name:
    Tyler
    Fort McMurray, Alberta
    Vehicle:
    09 MGM 4Banger 4x4
    5% tint all around, Alpine IVA-W505, 16x8 Mojave Teflon Rims w/Hercules Terra Trac 265/75, Grillcraft Grill, Slimcubby HIDs, Front 5100's @ 0 w/Eibach 1.6" springs, URD Short Shifter, Extang Trifecta Tonneau Cover, Uniden Pro510XL and K30Mag Mount, Relentless Fab Bumper soon to come
    so lately my trucks mpg has dropped pretty significantly, and i seem to be getting horrible hwy mileage specifically. About 17 or 18. city hasnt really been affected much around 19, 20. but i used to be getting around 24hwy. i do about 75% hwy driving so i'm starting to get a little worried here. i noticed it dropped dramatically after i filled up with octane94 fuel from a sunoco station and since then ive been using 89. but ever since that tank of 94 it hasnt been the same at all. i recently got a larger tire size as well, 265/75's from the stock 245/75's. i know this would have some effect on mileage but not the huge decrease im experiencing. any suggestions? perhaps a bad batch of fuel contaminated the system?:confused::confused::confused::confused: ive filled up 4 or 5 times since using the 94 so i'm out of ideas...
     
  2. Aug 12, 2009 at 2:07 AM
    #2
    justeday

    justeday diving fanatic

    Joined:
    Sep 3, 2008
    Member:
    #8984
    Messages:
    20
    Gender:
    Male
    campbell river, BC
    Vehicle:
    06 toy tacoma, silver mica
    265/75/16, bed mat, knaak tool box, custom headache rack with side rails,rear floods, rear rack, sirius
    i recently got a horrendous fill from a tempo around here.... so pathetic..... went 60 km on a quarter tank with a load, but no excessive speed etc... filled up at a petro can.... and got over 110 km on a quarter tank... maybe bad gas?, will stay away from tempo for now...
     
  3. Aug 12, 2009 at 4:32 AM
    #3
    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
    The simplest answer is usually right...its probably the larger tires. Added rotational weight can make a huge difference in acceleration and gas mileage, especially on torque deficient engines like our 4 bangers.
     
  4. Aug 12, 2009 at 5:18 AM
    #4
    coma09

    coma09 Senior Member. Hey, what's That supposed to mean?

    Joined:
    Jun 22, 2009
    Member:
    #18751
    Messages:
    210
    Gender:
    Male
    BC Canada
    Vehicle:
    2013 taco access cab 4x4
    Putco led map light bulbs, bed mat, Xiang trifecta tonneau, blackout front emblem, paint tow hoop, led bed light strip, scan gauge II, debadge, buff paint, oem fog light kit, 1000w inverter, Viair 300P compressor, Contura V dash switches, chop last L bend from exhaust, remove charcoal air filter, extinguisher, mag light, Ss side steps, kayak rack, tailgate security, bed mat security
    How much bigger tires?
    You can simplify the analogy to a lever arm working against your axle shaft. Larger diameter tire, longer lever arm the axle has to move against the rolling resistance, inertia of vehicle weight, as well as wind resistance.
    The rolling resistance will be a bit different with different tire construction/materials. Could be better, or worse than previous tires.
    The engine has to constantly work harder with larger diameter tires.
     
  5. Aug 12, 2009 at 6:11 AM
    #5
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

    Joined:
    May 8, 2008
    Member:
    #6497
    Messages:
    106,158
    Gender:
    Male
    First Name:
    FlimFlubberJAM
    Tenoe, AZ
    Vehicle:
    2013 Rubicon Unlimited,
    4.10 gears, sliders, and lots of buttons.
    Are you adding 4% to the ODO reading before dividing the gallons used? The new tire is 4% larger, so you need to take that into account.
     
  6. Aug 12, 2009 at 6:13 AM
    #6
    FL Forester

    FL Forester Well-Known Member

    Joined:
    Aug 23, 2008
    Member:
    #8706
    Messages:
    1,035
    Gender:
    Male
    First Name:
    Jason
    Tallahassee, FL
    Vehicle:
    2014 MGM Double Cab
    None yet
    How many miles are on your truck? It could be time to clean the intake out.
     
  7. Aug 12, 2009 at 6:27 AM
    #7
    coma09

    coma09 Senior Member. Hey, what's That supposed to mean?

    Joined:
    Jun 22, 2009
    Member:
    #18751
    Messages:
    210
    Gender:
    Male
    BC Canada
    Vehicle:
    2013 taco access cab 4x4
    Putco led map light bulbs, bed mat, Xiang trifecta tonneau, blackout front emblem, paint tow hoop, led bed light strip, scan gauge II, debadge, buff paint, oem fog light kit, 1000w inverter, Viair 300P compressor, Contura V dash switches, chop last L bend from exhaust, remove charcoal air filter, extinguisher, mag light, Ss side steps, kayak rack, tailgate security, bed mat security
    An easy experiment would be to disconnect the battery for ~ 5 min. to reset the ECM. Really reaching here, but it's possible the Sunoco fuel (in Canada, Sunoco uses up to 15% ethanol) caused the ECM to adapt to the Sunoco, and hasn't re-adapted.
    Seems logical a sudden change in economy like that has to have a root cause.
    Tires, gas ... any other changes near then?
     
  8. Aug 12, 2009 at 6:46 AM
    #8
    Brunes

    Brunes abides.

    Joined:
    May 31, 2008
    Member:
    #7011
    Messages:
    17,641
    Gender:
    Male
    First Name:
    Rotorhead
    DC or New Jersey - Depends on the day....
    Vehicle:
    08 Red/Graphite and Satin Black
    Inside: Tint, Wet Okole 1/2 Piped Red/Black Covers, Black Weathertech Digital Fit Mats, URD Short Throw w/ TWM Weighted Knob, USA Spec iPod adapter. Outside: 4300K Retro w/ Angel Eyes and Red Shrouds, 5000K Blazer Fog Light Retrofit, Debadge, Bed Locking Handle, Satin Black Rims Performance: TRD/Steigmeier Blower w/ 2.7 Pulley. 668 Injectors and 320 LPH AEM Fuel pump. URD UCON and 7th Injector. DTLT Headers, URD Y-Pipe, Wicked Flow Muffler. Suspension: Both: OME Shocks Front: 886X's and TC UCAs Rear: Dakars Armor: Relentless Front Bumper Relentless High Clearance Rear w/ Tire/Rotopax Swing Out Relentless Front, Mid, and TCase skids BAMF Diff Skid Recovery and Spares: Fullsize Spare Tire 2x2 gal Rotopax 1x1 gal Rotopax 1x1 gal Water Rotopax Warn 9.5XP-S Winch Hi-Lift Extreme 60" Ironman Off-Road Recovery Kit
    +1- Between the larger/heavier tires and the changes they make to the measurements you are using to calculate gas mileage...You might find alot of those lost mpgs.
     
  9. Aug 12, 2009 at 8:12 PM
    #9
    chad68

    chad68 Master Jedi Member I am...

    Joined:
    Oct 28, 2007
    Member:
    #3263
    Messages:
    1,080
    Gender:
    Male
    First Name:
    Chad
    In a (Toyota) van down by the river! Sonoma Cownty
    Vehicle:
    2009 4x4 reg cab. Modded with more to come
    Polished 16x8 Pro Comp 1069's 4" BS Nitto Mud Grapplers 305/70/16 Magnaflow & glasspack muffler Stainless tip K&N 63 series Aircharger Vent visors Autometer volt and dig. temp. gauge custom mounted Factory chrome rear bumper (not black factory, one) TRD pedal covers TRD skid plate Hurst T handle shift knob Rear Tint Clear bra on the sides Chrome extinguisher Icon non resi coilovers, ICON RR shocks, black seat covers. And some other crap
    I get crappy gas milage with my 32's as well. You should keep in mind that if your ODO says you have gone 100 miles, with 32's you have actually gone more than 100 miles. Well actually that's not true either probablly, since the ODO is off from factory.

    I figure if it bothers me too much, I have a few choices. 1. Switch to 265/70/16's. 2. Regear. 3. Put even bigger tires on and regear. 4. Or just pay thru the nose for gas. So far I'm just buying lots of gas and whining about it, till I figure out what I'm going to do.
     
  10. Aug 13, 2009 at 11:30 AM
    #10
    ttylerr

    ttylerr [OP] Well-Known Member

    Joined:
    Jun 1, 2009
    Member:
    #17913
    Messages:
    833
    Gender:
    Male
    First Name:
    Tyler
    Fort McMurray, Alberta
    Vehicle:
    09 MGM 4Banger 4x4
    5% tint all around, Alpine IVA-W505, 16x8 Mojave Teflon Rims w/Hercules Terra Trac 265/75, Grillcraft Grill, Slimcubby HIDs, Front 5100's @ 0 w/Eibach 1.6" springs, URD Short Shifter, Extang Trifecta Tonneau Cover, Uniden Pro510XL and K30Mag Mount, Relentless Fab Bumper soon to come
    it started happening before the larger tires
    i'm almost positive the sunoco station i fill up at is 10% ethanol
    my truck only has 10000km (~6200mi) on it, all on-road so far so i really shouldnt have to clean anything out on the intake side yet, but ill look
    ill give resetting the ecu a try as well but i think i already did that when i installed my hids and had the battery disconnected

    thanks for the suggestions
     
  11. Aug 13, 2009 at 11:33 AM
    #11
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

    Joined:
    May 8, 2008
    Member:
    #6497
    Messages:
    106,158
    Gender:
    Male
    First Name:
    FlimFlubberJAM
    Tenoe, AZ
    Vehicle:
    2013 Rubicon Unlimited,
    4.10 gears, sliders, and lots of buttons.
    Actually, Its pretty accurate.
     
  12. Aug 13, 2009 at 4:34 PM
    #12
    Taco505

    Taco505 Well-Known Member

    Joined:
    Feb 15, 2009
    Member:
    #13659
    Messages:
    2,568
    Gender:
    Male
    First Name:
    Alex
    New Mexico
    Vehicle:
    08 4cly
    Dule Magnaflow Exhaust dumped behind axle, K&N Air intake, Aftermarket radio with a kicker L5 sub & a shit amp, 18" rims with tires, RHLM, DT header, color matched bumper, oem foglights, 8k hids in headlights and in fogs
    i agree with the two above i noticed the same thing with my truck when i changed the tire size. i went from the stock size to about 30's. but i know this is kinda a weird way of thinking about it but out trucks (4bangers) are like little kids, when a little kid puts on their dads shoes it takes more power for them to get going, to stay at the same speed, and also to slow down. haha
     
  13. Aug 14, 2009 at 12:24 PM
    #13
    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
    Whats your definition of "pretty". Its reads about 2.5 mph faster at 55 mph. Thats not as accurate as most other vehicles I've driven.
     
  14. Aug 14, 2009 at 12:58 PM
    #14
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

    Joined:
    May 8, 2008
    Member:
    #6497
    Messages:
    106,158
    Gender:
    Male
    First Name:
    FlimFlubberJAM
    Tenoe, AZ
    Vehicle:
    2013 Rubicon Unlimited,
    4.10 gears, sliders, and lots of buttons.
    The speedo, Yes. The ODO is just about right on the money.
     
  15. Aug 14, 2009 at 8:21 PM
    #15
    Raven65

    Raven65 Well-Known Member

    Joined:
    Feb 27, 2009
    Member:
    #14150
    Messages:
    361
    Gender:
    Male
    Camden, SC
    Vehicle:
    '09 Magnetic Gray Reg Cab 5-Lug
    Curt hitch, D-rings, bed mat
    True statement. This was discussed ad nauseum in another thread. The gist of it is that although the speedo and odo receive their input from the same source (the VSS - vehicle speed sensor on the output shaft of the transmission), the odo is a direct digital-to-digital representation (and is accurate) while the speedo converts that digital signal to an analog representation (needle movement) - and it's not totally accurate.
     
  16. Aug 15, 2009 at 2:28 PM
    #16
    91r100gs

    91r100gs Understand the Voice Within

    Joined:
    Apr 21, 2008
    Member:
    #6100
    Messages:
    655
    Gender:
    Male
    First Name:
    Dan
    Kansas City area
    Vehicle:
    '08 Impluse Red SR5 I-4
    Factory bed mat, TacomaWorld.com sticker, EGR In-Channel Vent Visors, AFE ProDryS drop in air filter
    My 2008 5-lugger read 60 at a real 55, and the odometer reads 101.5 miles for every 100 interstate mile markers. Have checked the odometer on 3 different stretches of interstate and they all read the same.
     
  17. Aug 16, 2009 at 7:33 PM
    #17
    "OldManTan"

    "OldManTan" Now my Taco is bloody Red, ewww

    Joined:
    May 18, 2009
    Member:
    #17401
    Messages:
    1,239
    Gender:
    Male
    Buffalo, NY
    Vehicle:
    08 Access Cab, Radiant Red
    Pioneer HU, Duratracs on Black stockers, Century topper with custom electronic lock, Illuminated 4x4 switch, Foglight Mod, Always on 12v Plugs, Sub & Amp, LED Interior Lights, Cup Holder Mod, Andres Devil Horns, CB radio, steps, relocated trailer harness, blacked out everything!!
    Have you checked to make sure a brake isn't hung up. Happened to me on my "other" truck, and lost about 4-4.5 mpg until I figured it out. Checking the temperature of the rim, carefully, after a drive is a pretty good indicator.
     
  18. Aug 16, 2009 at 7:44 PM
    #18
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

    Joined:
    May 8, 2008
    Member:
    #6497
    Messages:
    106,158
    Gender:
    Male
    First Name:
    FlimFlubberJAM
    Tenoe, AZ
    Vehicle:
    2013 Rubicon Unlimited,
    4.10 gears, sliders, and lots of buttons.
    [quote="OldManTan";855800]Have you checked to make sure a brake isn't hung up. Happened to me on my "other" truck, and lost about 4-4.5 mpg until I figured it out. Checking the temperature of the rim, carefully, after a drive is a pretty good indicator.[/quote]
    X2! I useually check my temps after any long drive to get an idication of how the bearings are doing, brake sticking, or whatever.
     
  19. Oct 8, 2009 at 7:23 PM
    #19
    Y0TA

    Y0TA TW Addict

    Joined:
    Jan 31, 2009
    Member:
    #13145
    Messages:
    612
    Gender:
    Male
    First Name:
    Zac
    Missoula
    Vehicle:
    05 BLK TRD Sport 4X4
    15% tint, debadged, painted black interior, 50s Flowmasters, K&N, Tailgait theft mod, Leer Topper, Sirius Sat Radio, BHLM, 4300k HIDs, DTRL mod, Metra Ipod adapter, Hella 500 behind black billet grille, OME 885s w/ AAL, Light Racing UCAs, Weathertech liners, Konig countersteers w/285s M/Ts, Scangauge II, 886 bulbs, Aux. reverse lights, Custom Bumper with Westin 8500 winch, Marathon camo seat covers
    I noticed this on my scangauge after i filled up. i usually do alot of highway driving and get about 18-19 mpg, but now i am getting like 11 or 12. i don't know what the deal is. maybe im not restting my scangauge right after a fillup?
     
  20. Oct 8, 2009 at 7:28 PM
    #20
    jwhelan

    jwhelan Well-Known Member

    Joined:
    Sep 19, 2009
    Member:
    #23006
    Messages:
    431
    Gender:
    Male
    First Name:
    JW
    Dallas Texas
    Vehicle:
    05 TRD Silver
    TRD PreRunner, 5100's on all four fronts @ 1.75, AAL, SP performance rotors, hawk pads, 17" FJ Cruiser wheels P/C black, 265/65/17 BFGR Rugged Trails, BHLM , painted grill, blacked out emblems

    You beat me to it...exactly the prob
     
To Top