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Thread: Will Getting a New PCM Help

  1. #1
    Join Date
    Jun 2003
    Posts
    8
    I have a 99 GMC ECSB w/ a 99 TA LS1. Only mods are polished throttle body, UPD lid, 373 gears w/eaton locker. I used the truck intake.

    I am getting 8 degrees of knock retard, beginning at about 70% throttle. Other than that the truck runs great. 250 rwhp & 296 lb/ft of torque.

    I have run 100 octane and the knock is still there.

    If I purchase a new PCM and program it will this get rid of the knock?

    If I replace the knock sensors? The sensors for the LS1 and the 5.3 are the same.

    Thanks,

    Tony
    99 GMC, ECSB w/ LS1 from 99 TA
    E-fans, 3:73, Eaton posi

  2. #2
    Join Date
    Sep 2003
    Location
    Cedar Park, TX
    Posts
    193
    Sure sounds like false knock if its still there with 100octane gas. Not sure if a PCM will help you out. Try putting a 10k resistor in line with each knock sensor to desensitise them and if it helps, I would go after replacing them.

    Mike
    '02 1500HD, 6.0L, magnacharger, 2000stall, custom magnaflow with electric cutout, E-fans, Nelson custom tune, Auburn LSD.
    '79 L82 vette, Summit 355, Dart Pro1 heads, Comp 274 cam, Holley TBI, Built TH350 with 2500stall
    '93 Blazer, full size 2dr 4x4, new project.....

  3. #3
    Join Date
    Mar 2003
    Location
    San Antonio, TX
    Posts
    11,038
    If that doesn't work, try getting your PCM reflashed with a newer calibration. GM comes out with many updates to the PCM and sometimes it's for knock.

    go to http://calid.gm.com:8082/VINEntryPre.do and see if there's any updates.

    if so, I can flash your pcm for you.


    later,

    allen

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