Results 1 to 8 of 8

Thread: Idle runs away

  1. #1
    Potential Tuner
    Join Date
    Jan 2016
    Posts
    7

    Idle runs away

    the engine is an L96 out of a 2012 silverado, with e78 ecm. Mods are long tube headers, camaro ls3 intake manifold and injectors, larger intake and maf housing, twin plate button clutch/lightweight flywheel. It seems to start nicely but then starts to rev away on its own while its opening the throttle blade more. I added 20% to the maf frequency table, 20% to the torque model. I took away 50% from idle external load and 50% from Idle speed reserve. This is the best its so far. Wondering if im going in the right direction fuel trims are still adding roughly 18 percent so i was gonna add more to the maf frequency table. Thanks in advance.
    Attached Files Attached Files

  2. #2
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,533
    You are positive you have no vacuum leaks causing it to run a higher idle and make the fuel trims worse?

    That is, if you haven't taken the time to redo the MAF and VVE to fix the fueling first. These computers use both the MAf and VVE, so only doing the MAF with the VVE still working is only half the battle.

    I'd worry about idle more when the airflow model is corrected better. Doing idle airflow tuning with the fueling still off will be really hard to fix, if not impossible because it's still fighting itself.

    Also worth it to make sure with a mechanical gauge that you are running the 58psi of fuel pressure.

    Use your wideband to create an AFR or lambda error against the commanded AFR/Lambda. Stick the calibration into speed density only to tune the VVE or MAF only to tune the MAF with closed loop and the fuel trims disabled. Get the error dialed in really close and switch back to closed loop with fuel trims, see how things got then.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Has anyone messed with DD tables? Or torque tables? Those will cause it to run away.

  4. #4
    Potential Tuner
    Join Date
    Jan 2016
    Posts
    7
    It was vacuum leaks... still double checking, havent had much time to work on it this week. Thanks, I will report back after I test it out.

  5. #5
    Potential Tuner
    Join Date
    Jan 2016
    Posts
    7
    I fixed the vacuum leaks and tested again and didn't find anymore. I loaded up an unmodified tune and it started nicely but shortly after the throttle blade started opening and the engine revved up past 2000rpm and was still fairly lean. Should I tune the maf frequency table and vve table now?after vacuum leak.hpl
    Last edited by e39l96; 05-10-2019 at 06:29 PM. Reason: add log

  6. #6
    Tuner in Training DanSchafer93's Avatar
    Join Date
    Jul 2018
    Location
    PNW
    Posts
    37
    Where were your vacuum leaks? I have the same set up in my K2500 square body and am having the exact same issues. Its a 2012 L96 6.0L with Long tube headers and a Cold air intake. besides that it is completely stock out of a 2012 sierra 3500HD. I only have this problem in closed loop but I have been chasing my tail on this for a while now... Any info would be helpful..

  7. #7
    Tuner 5ft24's Avatar
    Join Date
    Mar 2018
    Location
    Sedro Woolley, Washington
    Posts
    110
    Are you still running the stock throttle body or did you put a different one on? There are silver blade and gold blade. If you put the wrong one on, the engine vacuum can pull the TB open
    2006 Pontiac GTO
    M6
    Flex Fuel enabled
    FIC1000 shorty Injectors
    DW300C Fuel pump
    UPP GTO Auxiliary fuel system
    BoostDistrict LSA Conversion
    BTR Stage 3 PDS Torque cam and kit
    Kooks Longtube headers with High Flow Cat mids
    BoostDistrict LSA CAI with LS7 MAF module
    Mickey Mouse Catch Can
    Hinson 1/2" lowered Engine Mounts
    Magnaflow 3" Cat Back Competition Exhaust
    PLX DM-6 Wideband
    Turbo Technologies Full Flex fuel Tune

  8. #8
    Senior Tuner SultanHassanMasTuning's Avatar
    Join Date
    Nov 2009
    Location
    All Around
    Posts
    3,149
    maybe your injector is not seated properly
    Follow @MASTUNING visit www.mastuned.com
    Remote Tuning [email protected]
    Contact/Whatsapp +966555366161