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Thread: Twin Turbo 4.8 wont come off idle

  1. #1
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    Default Twin Turbo 4.8 wont come off idle

    I have a twin 60mm turbo setup on a 2001 silverado 4.8l running mafless 2 bar cos3. 42lb injectors. It has a loping idle and when the throttle is tipped the engine dies. Anyone have any ideas?01 boost master.ctz. The only way to get it off idle is to set the B3647 table extremely rich.
    Last edited by mgnta217; February 15th, 2018 at 10:57 AM.

  2. #2
    Joe (Moderator) joecar's Avatar
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    I'm looking thru your .ctz and I see some things...

    B3647: columns 95 kPa and 100 kPa are extremely lean, 0.9434 EQR and 0.8545 EQR... check your fuel display units (you will find they are set to Lambda), set them to EQR, restart tunetool, redo B3647.

    B3616: do you want PE to enable when throttle reaches 90% or higher...? I think you should reduce this to enable PE much sooner.

    B3609: you probably want to set this to 0.010 s.

  3. #3
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    I fixed the B3647, B3616, and B3609 tables, I think. It barely idles now and still can't touch the accelerator without it dying.01 boost master.ctz

  4. #4
    Joe (Moderator) joecar's Avatar
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    Post some log files.

  5. #5
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    Ok, so I got aggravated and just built an entire new tune using the custom os tutorial. It will now start and rev, but has a misfire on 4 cylinders and is running rich.

  6. #6
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    Update, It is running fine and comes off idle perfect. found the issue was my MAF codes were set to not report instead of non emission. Thanks a ton for your help tho. Thats the reason efilive is the best!

  7. #7
    Joe (Moderator) joecar's Avatar
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    Good job

    ( there was another thread where MAF DTC was set to not-reported )

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