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Thread: LS1B 8.1/4l85 with failed hypertech tune assistance

  1. #11
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    Quote Originally Posted by Phil_Miller_86 View Post
    This is the only file I have from the PCM and it contains an error.

    Attachment 23889
    LS1B_2004 Avalanche 8.1L 4x4.ctz
    This should be the latest OEM base file for you based on the Vin number from the file you provided. Hope this helps!

  2. #12
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    Update:

    I received my new PCM in the mail and installed it. I had to do the passkey learn process like three times because the tutorials didn't say I had to try and start it each time to get the light to come on.

    It idles kinda rough, and I haven't done the crank learn yet because it's kinda late to be revving up to 4000rpm.

    I was able to pull a stock tune file(!) so I have something to start with. I need to adjust the tire size and gear ratio to keep from cooking the tranny while I drive it around and get all the systems ready for logging and tuning.

  3. #13
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    Quote Originally Posted by Phil_Miller_86 View Post
    Update:

    I received my new PCM in the mail and installed it. I had to do the passkey learn process like three times because the tutorials didn't say I had to try and start it each time to get the light to come on.

    It idles kinda rough, and I haven't done the crank learn yet because it's kinda late to be revving up to 4000rpm.

    I was able to pull a stock tune file(!) so I have something to start with. I need to adjust the tire size and gear ratio to keep from cooking the tranny while I drive it around and get all the systems ready for logging and tuning.
    Obvious question, but was the stock tune file for an 8.1? I only ask because I feel like it shouldn't idle rough.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  4. #14
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    Quote Originally Posted by Supercharged111 View Post
    Obvious question, but was the stock tune file for an 8.1? I only ask because I feel like it shouldn't idle rough.
    It was put on the PCM by the company that sold it to me based on my VIN. In the very beginning it's a little stumble, the RPM's dip, and then it comes back up.

  5. #15
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    04 Avy Stock tune w hypertech trans data and fixed speedo.ctz

    Can someone with some experience take a look at this and tell me if it looks reasonable/safe?

    I tried to copy the hypertech-tuned transmission data over from the bad speedo file to the new stock file that was on the PCM, with my calculated speedometer values. The old trans data is from an older operating system, so I don't know if it's okay to put that data on the new PCM running the newer OS?

    I'm moving this week, towing a trailer ~700 miles and don't want to burn my tranny up with bad data (stock or otherwise).

  6. #16
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    Quote Originally Posted by 1FastBrick View Post
    LS1B_2004 Avalanche 8.1L 4x4.ctz
    This should be the latest OEM base file for you based on the Vin number from the file you provided. Hope this helps!
    I thought I posted a reply to thank you, but I don't see it here. I appreciate your help, Thank you.

  7. #17
    Joe (Moderator) joecar's Avatar
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    Use the V7 scantool.to write the VIN.

    Why did you have to replace the PCM?

    Don't go to the dealer for PCM flashing... they are instructed to lookup the factory bulletins and flash what the bulletins indicate (from the factory database) and/or to replace the PCM (you don't know what they actually did).

  8. #18
    Joe (Moderator) joecar's Avatar
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    I'll look at your files when I get home from work (next Tuesday).

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