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Thread: New engine, popping under boost??

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  1. #1
    Join Date
    May 2008
    Location
    wichita falls, tx
    Posts
    613
    i have the exact same problem but mine goes completly away when my motor warms up so keep us posted

    Junkyard 5.3 milled heads 200 shot, built 4l80e with circle D 4000 multi disc converter
    EPS cam 23x/23x 600/603 112lsa
    KP 6 link bagged with Accuair E-Level
    http://www.nitrousexpress.com/

  2. #2
    Join Date
    Nov 2003
    Location
    Denton Texas
    Posts
    20,540
    Bad valve springs? Weak? Wastegates popping early?
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  3. #3
    Join Date
    Mar 2003
    Location
    San Antonio, TX
    Posts
    11,038
    Quote Originally Posted by GasGuzzler View Post
    Valve float, broken valve spring, poor sealing valve seat, cam advanced or retarded, low fuel pressure, faulty MAF (if MAF tune), CKP failure, loose reluctor, incorrect reluctor....
    valve float at 4krpms and 3psi with good springs, probably not, but i'll check the springs, a bad spring could cause valve float.
    could be poor sealing valve, i'll check that.
    cam in straight up, runs too good under no boost conditions.
    fuel pressure, rock solid! a1000, -10 line everywhere, aero fpr.
    no maf
    i hope it's not ckp or wheel, that would suck!
    i don't think it's the wrong wheel, it would backfire and spit randomly and a lot more often.

    Quote Originally Posted by TurboMic View Post
    i say some plug wires burned on the turbo manifold.....like mine did on us.....lol
    changing those tomorrow.

  4. #4
    Join Date
    Jan 2006
    Posts
    2,590
    Do you remember when you had mine on the dyno? It ran good until you got on it and started sputtering. Turned out to be a burn plug wire.

    Quote Originally Posted by farmtruc View Post
    valve float at 4krpms and 3psi with good springs, probably not, but i'll check the springs, a bad spring could cause valve float.
    could be poor sealing valve, i'll check that.
    cam in straight up, runs too good under no boost conditions.
    fuel pressure, rock solid! a1000, -10 line everywhere, aero fpr.
    no maf
    i hope it's not ckp or wheel, that would suck!
    i don't think it's the wrong wheel, it would backfire and spit randomly and a lot more often.


    changing those tomorrow.
    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***

  5. #5
    Join Date
    Sep 2007
    Location
    Texas
    Posts
    5,301
    fuel pressure regulator?

  6. #6
    Join Date
    Aug 2008
    Location
    North Texas
    Posts
    12,078
    Quote Originally Posted by dropem View Post
    i have the exact same problem but mine goes completly away when my motor warms up so keep us posted
    Classic lean or low volume fuel problem.

  7. #7
    Join Date
    Mar 2003
    Location
    San Antonio, TX
    Posts
    11,038
    Quote Originally Posted by dropem View Post
    i have the exact same problem but mine goes completly away when my motor warms up so keep us posted

    When the engine is cold, open loop, the pcm is using the ve table. If the ve table isn't rich enough, your engine could be experiencing a slight lean condition. When it gets warm, the the maf takes over and patches everything. The ltrims are probably positive, and the pcm adds fuel, which corrects the lean pop.
    Or, the fuel pump isn't good enough.

  8. #8
    crap 4 pages long.... I guess I should pay more attention
    03 2500 HD
    05 CBR 1000rr

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