+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 10 of 13

Thread: Colder weather affecting AFR?

  1. #1
    Join Date
    Feb 2007
    Location
    Spring, Texas
    Posts
    1,739

    Colder weather affecting AFR?

    Why is it that when the temperatures outside start to drop (anywhere from mid 60's and below) that I start running lean? When temps are around 75, I'm consistent at 11.4 but when it gets colder my AFR is 12.0. Any ideas/suggestions?

    2004 Silverado Crew Cab, forged iron 5.7, STS w/MP turbo, 10+ psi, FMIC, Tial 50mm BOV, Vic Jr, Snow performance meth, MTI Stealth cam .220/.220 .581/.581 115lsa, Comp chromoly pushrods, Yank TT3000 stall, LS1 Efans, 160 tstat, Trucool 40k trans cooler, 60# injectors, Walbro fuel pump, Patriot springs, Built 4l65E w/billet input & output shafts, Eaton posi, SD tuned...all installed by Klein North Automotive

  2. #2
    Join Date
    Aug 2008
    Location
    North Texas
    Posts
    12,078
    Cooler air is denser.

  3. #3
    Join Date
    Apr 2005
    Posts
    4,229
    Yup. I believe that is a drawback to the SD tune?
    Gone, but not forgotten!

  4. #4
    Join Date
    Mar 2003
    Location
    San Marcos Texas
    Posts
    4,393
    It should still be the same. Maybe a retune? I've run mine way down into the 20's and had the same readings.
    2006 Superior Blue Trailblazer SS AWD, Stock as a rock

    Sold: 2002 GMC Sportside Denali front end with a 2002 LS1, FLT level 5, Yank 2600, Trick Turbo, T76, Nelson intercooler, 60LB injectors, Warbro fuel pump, Eaton locker, Magnaflow, 3.42, Nelson Performance Tuning (speed density).

    Sold: 1981 GMC LB RC 1500 2002 4.8L 4L60E 12 bolt 3.73 Richmond Lock Right AC PS Nelson Performance tuning

  5. #5
    Join Date
    Aug 2005
    Location
    St. Anthony, Indiana
    Posts
    1,592
    I haven't noticed any change to mine when it gets cold.

  6. #6
    Join Date
    Jan 2006
    Posts
    2,590
    11.5 - 11.7 all temps?
    12 Sec. Club! SOLD
    La Viuda negra/ a.k.a. Black Betty

    LQ4 6.0L, WCCH HEADS, LEVEL 5 FLT 4L80E TRANS. WITH TRANS BREAK, YANK 3200 STALL, TRICK TURBO, TURBONETICS T-76 TURBO, CUSTOM INTERCOOLED, 68lb INJECTORS, CUSTOM S/D TUNE FROM NELSON PERFORMANCE, COMP CAM 212/214 .557/.559 116+2, SNOW METH. KIT, . ALL INSTALLED AND DYNOED AT NELSON PERFORMANCE: 5**?HP @ 5073rpms and 5**TQ @ 4389rpms AT THE WHEELS WITH 10 PSI OF BOOST. ALL 3/4 TON TRUCK 5435LBS, NOTHING TAKEN OFF, STREET TIRES, AND USUALLY 2 BABY SEATS. WANNA RIDE?
    SOLD***

  7. #7
    Join Date
    Feb 2007
    Location
    Spring, Texas
    Posts
    1,739
    Kinda weird. I noticed this morning (65 degrees) that when I hit full boost, my AFR went to high 11's low 12's. During the day, with temps in the 70's or 80's, my AFR was in the low 11's. Not sure what's going on but I need to figure it out quick!

    2004 Silverado Crew Cab, forged iron 5.7, STS w/MP turbo, 10+ psi, FMIC, Tial 50mm BOV, Vic Jr, Snow performance meth, MTI Stealth cam .220/.220 .581/.581 115lsa, Comp chromoly pushrods, Yank TT3000 stall, LS1 Efans, 160 tstat, Trucool 40k trans cooler, 60# injectors, Walbro fuel pump, Patriot springs, Built 4l65E w/billet input & output shafts, Eaton posi, SD tuned...all installed by Klein North Automotive

  8. #8
    Join Date
    Jul 2005
    Posts
    27
    Again, its because the cooler air packs more O2 molecules into your cylinders while your injectors are still delivering the same amount of fuel. Thus changing your a/f ratio.

    Do you notice more power? If you arent getting any detonation, dont worry about it.

    MAybe there is some sort temp multiplier that was shut off in your tune accidentally?

    peace
    Hog.
    97 GMC 2wd RCSB 5.7, s10 2700 footstall, Hooker 24621hkr LT's , 2.5" cats dual 4"pipes exit B4 pass. side tire, custom driveshaft 3.42 G80 FIPK MAF descreen GM/Mercruiser Marine intake manifold 29lb LS2(EV6) injectors Ed Wright PCM(best mod), LT4 KM 14.8@94mph 2.007 4000lbs 122mph

  9. #9
    Join Date
    Feb 2007
    Location
    Fort Worth
    Posts
    9,578
    Quote Originally Posted by hog View Post
    MAybe there is some sort temp multiplier that was shut off in your tune accidentally?

    peace
    Hog.
    Yeah Jay--have Allen look at the temp multiplier tables in the tune. I know HPT has a section where (depending on IATS), it will automatically change your timing or AFR in relation to the temps...

    2000 ECSB 6.0L
    TORQUER V2 CAM ● COMP 918's ● 7.4 HARDENED PUSHRODS ● K&N SERIES 77 CAI ● 80mm BBK ●PACESETTER LT HEADERS AND 3'' ORY ● SUPER 40 FLOW ● 3000 STALL ● 4.10s ● BUILT 80e ● VORTEC PERFORMANCE TUNE ● MSD 8.5mm PLUG WIRES● ELEC. CUTOUT ● UD & ALT PULLEYS ● FLEX-A-LITE E-FANS ● 22" CENTERLINE STINGRAY III's ● LUND FIBERGLASS TONNEAU ● 2" LEVELING SHACKLES ● 12K HID LOWS & FOGS ● LEDs ● DEBADGED ● WHITE-FACED ESCALADE GAUGES ● KICKER 450.1 ● 2-CVR 10's ● DS60's ● K693's

  10. #10
    Join Date
    Jun 2004
    Location
    george west texas
    Posts
    3,694
    if your not hearing any kr dont worry about it...
    '13 silverado LT...stock

    '11 lt 4x4 z71..tvs1900

    '01 gmc twins 6.0 jakes 400 ladder bars w/ coilovers tuned by nelson performance

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts