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Thread: 5.3 swap issues

  1. #1

    5.3 swap issues

    Working on a 2003 Sierra, originally a 4.8 swapped in a 5.3 .. Installed a Trailblazer ss intake manifold, small truck Norris cam
    Loaded in a stock 5.3 tune worked on the throttle body scalar ,deleted rear O2 sensors ,made changes to base idle airflow etc
    Runs down the road well but stalls a minute after it comes to idle, Disabled throttle cracker to stop hanging throttle.
    was throwing code p0101 intermittantly so I replaced maf sensor. Still stalls sometimes. code returns .
    From cold start during warm up still in open loop fuel trims go crazy from taking fuel out to adding fuel and will stall

    attached is the last read from ECM and a couple logs If someone could have a look and point me in the right direction that would be
    appreciated Thanks
    Attached Files Attached Files

  2. #2
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    P0101 is a predicted airflow diagnostic. You changed the airflow with a larger displacement engine, a cam and a different intake manifold. So the amount of airflow through the MAF is not what is expected or predicted. I don't know why people just automatically change a sensor when a diagnostic for that sensor fails without researching what the diagnostic is checking. But parts stores love people that do that. Just open up the limits for the diagnostic in the Engine Diag>Airflow tab. Multiply the entire table by 2, 3, or even 4. X4 will set the table pretty close to what the earlier 99-01 calibrations have. Starting in 02 GM started tightening up the tolerance on that diagnostic for no rhyme or reason and by 03 and up it is even tighter.

  3. #3
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    And if you put a parts store brand MAF junk on it I would put the original Delphi MAF back on it.

  4. #4
    Quote Originally Posted by 2xLS1 View Post
    And if you put a parts store brand MAF junk on it I would put the original Delphi MAF back on it.
    Thanks for the reply Yes I agree I dont usually throw parts at it. I just happened to have a OE maf on the shelf

  5. #5
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    The rest of your problems is just tuning for the cam. Although the IAC passageways on the Chinese throttle bodies can cause some of those issues too.

  6. #6
    Quote Originally Posted by 2xLS1 View Post
    The rest of your problems is just tuning for the cam. Although the IAC passageways on the Chinese throttle bodies can cause some of those issues too.
    Yes first thing I did was purchase the genuine GM throttle body ,

  7. #7
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    Sorry I got your thread mixed up with another I was reading that was using a Chinese TB. No IAC on a 03 ETC

  8. #8
    No problem, I was just hoping someone would look at the tune file to see if I messed anything up when I first loaded the 5.3 parameters in the ecm which was originally a 4.8 set up
    I am pretty new at this . I think I got the throttle body scalar correct .

  9. #9
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    Quote Originally Posted by RicksPerf View Post
    I am pretty new at this . .
    didyou start with this thread? https://forum.hptuners.com/showthrea...e-(w-pictures)

  10. #10
    I did a few of the steps , I never saw that thread but it looks very helpful Thanks