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Thread: C7 Z06 boost issues

  1. #1
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    Question C7 Z06 boost issues

    Hello all, I'm currently working on a c7 Z06 that won't boost. I'll attach a tune file and a log, and you can look through it, but I've ran through all the physical things that could be affecting it, so the tune is my last bet. Any advice/recommendations would be greatly appreciated.

    C7Zbase_stock_tune.hptC7Zlogrun1.hpl

  2. #2
    In the log you reached 164kpa.
    Looks like you are being allowed boost.
    What made you think you didn't boost?

    The boost control on the Gen V motors is very picky.
    You need to ensure your MAF doesnt go into a failed state.
    You must not have any airflow DTC's Disabled either.
    You need to ensure you do not have any airflow or throttle errors.
    The intercooler must be working properly.

  3. #3
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    Make sure your BPV solenoid is connected properly. Also, you need to make sure you're monitoring the proper channel in the scanner or it will be wrong.
    [email protected]
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  4. #4
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    Throttle closed to 50% in the log. Most likely the issue...
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  5. #5
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    Quote Originally Posted by TriPinTaZ View Post
    Make sure your BPV solenoid is connected properly. Also, you need to make sure you're monitoring the proper channel in the scanner or it will be wrong.
    Which channel is the correct one to monitor? I thought the boost gauge front and center was the correct one. Solenoid is the next step, thanks for the replies.

  6. #6
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    Quote Originally Posted by will_974 View Post
    In the log you reached 164kpa.
    Looks like you are being allowed boost.
    What made you think you didn't boost?

    The boost control on the Gen V motors is very picky.
    You need to ensure your MAF doesnt go into a failed state.
    You must not have any airflow DTC's Disabled either.
    You need to ensure you do not have any airflow or throttle errors.
    The intercooler must be working properly.
    There are no codes other than the cat codes, which aren't disabled, and I'm sure the intercooler is working. Can you get a little deeper into the throttle error?

    I don't think I'm making boost because the car feels slower and the boost gauge on the dash isn't going above zero.

  7. #7
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    Hey GHuggins, what do you mean by that? The throttle wasn't down all the way? Or a different error within the software/throttle?

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    Quote Originally Posted by rileymeekpierce View Post
    Which channel is the correct one to monitor? I thought the boost gauge front and center was the correct one. Solenoid is the next step, thanks for the replies.
    I didn't look at your log. GHuggins seems to have found your issue though.
    [email protected]
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  9. #9
    Quote Originally Posted by rileymeekpierce View Post
    There are no codes other than the cat codes, which aren't disabled, and I'm sure the intercooler is working. Can you get a little deeper into the throttle error?

    I don't think I'm making boost because the car feels slower and the boost gauge on the dash isn't going above zero.
    If you had throttle errors, it would keep your max PR at .9 (according to the tune you posted)
    I do not think this is the issue here

    I opened up your log file.
    The MAP entry goes well past the baromoter
    165 = ~9.4 PSI of boost

    I dont see any issues with the log at all.
    9.4 psi of boost should put you back in your seat.
    Maybe there is knock? and it is pulling timing

    The throttle is down plenty.
    i see 60% accelerator pedal. and the actual throttle at 83 where it is supposed to live.


    log.jpg
    Last edited by will_974; 03-16-2023 at 12:37 PM.

  10. #10
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    Quote Originally Posted by will_974 View Post
    If you had throttle errors, it would keep your max PR at .9 (according to the tune you posted)
    I do not think this is the issue here

    I opened up your log file.
    The MAP entry goes well past the baromoter
    165 = ~9.4 PSI of boost

    I dont see any issues with the log at all.
    9.4 psi of boost should put you back in your seat.
    Maybe there is knock? and it is pulling timing

    The throttle is down plenty.
    i see 60% accelerator pedal. and the actual throttle at 83 where it is supposed to live.


    log.jpg
    Do you think that there's a reason that the in dash boost gauge isn't seeing this pressure? It does move, so it is working to some extent, but won't read above zero.

  11. #11
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    This isn't what you're complaining about?

    Before throttle closed with right at 60% pedal - you also need to fix PE settings here as you're in decent boost while still being in closed loop fueling.


    Before with nearly same pedal.jpg

    Then there's this one with the throttle closed to 50% - again with the pedal still roughly at 60%

    After with same pedal - throttle closed.jpg


    EDIT - I was looking at the wrong throttle position since you're logging several. I see now where the throttle closed you actually let off, so ignore the throttle closing statement Either way you still need to fix your PE settings.
    Last edited by GHuggins; 03-16-2023 at 02:37 PM.
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  12. #12
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    Quote Originally Posted by GHuggins View Post
    This isn't what you're complaining about?

    Before throttle closed with right at 60% pedal - you also need to fix PE settings here as you're in decent boost while still being in closed loop fueling.

    Either way you still need to fix your PE settings.
    I'm newer to gen5 - how is this particular power enrichment setting wrong? It's a stock tune file - the car is stock other than a catback exhaust. Would I change out the pe EQ ratio table for a leaner or richer mixture, or actually just change when PE kicks in through the PE delay(currently 0 ms delay)?

  13. #13
    If it was me,
    I would leave the stock tune and PE alone.
    If for no other reason that the powertrain warranty that would be lost with adjusting it.

    I wish i knew more about the dash board boost gauge. but alas, how the ecm controls the boost is the extent of my knowledge.

  14. #14
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    Quote Originally Posted by will_974 View Post
    If it was me,
    I would leave the stock tune and PE alone.
    If for no other reason that the powertrain warranty that would be lost with adjusting it.

    I wish i knew more about the dash board boost gauge. but alas, how the ecm controls the boost is the extent of my knowledge.
    I wouldn't think that a cat back would affect the pe table much if at all, thanks for the reply

  15. #15
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    If it's stock and you want warranty then don't modify anything...

    According to the log you posted it's at near full boost (166kpa) and still at a lambda of 1. It is still in the delay to activate zone but I've never known one of these to stay like that. Usually even with the OE settings it puts them into PE right when they're going into boost or just after and no - a catback shouldn't cause that. May just be how yours is?
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  16. #16
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    It could be that his sample rate for PE mode is set really long so it doesn't update immediately. I have found you have to adjust the sample rate in VCM Scanner for some PID's or they default to 1 second which is a couple thousand RPM depending on which gear you're in.
    [email protected]
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    Gen V Specialist - C7 Corvette, Gen6 Camaro & CTS-V3

  17. #17
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    Quote Originally Posted by TriPinTaZ View Post
    It could be that his sample rate for PE mode is set really long so it doesn't update immediately. I have found you have to adjust the sample rate in VCM Scanner for some PID's or they default to 1 second which is a couple thousand RPM depending on which gear you're in.
    I thought about that, but then I also looked at all of the other channels showing the same thing so just figured it wasn't going into PE?
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    ~Greg Huggins~
    Remote Tuning Available at gh[email protected]
    Mobile Tuning Available for North Georgia and WNC

  18. #18
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    Quote Originally Posted by GHuggins View Post
    If it's stock and you want warranty then don't modify anything...

    According to the log you posted it's at near full boost (166kpa) and still at a lambda of 1. It is still in the delay to activate zone but I've never known one of these to stay like that. Usually even with the OE settings it puts them into PE right when they're going into boost or just after and no - a catback shouldn't cause that. May just be how yours is?
    Full boost, now that I've been able to get the car to show it, isn't translation into power. I'm looking at the bypass solenoid, which when logging, never goes up past 0%(open and venting boost)

  19. #19
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    Quote Originally Posted by will_974 View Post
    If you had throttle errors, it would keep your max PR at .9 (according to the tune you posted)

    I dont see any issues with the log at all.
    9.4 psi of boost should put you back in your seat.
    Maybe there is knock? and it is pulling timing



    log.jpg
    Hey, it looks like there's minimal spark advance when the motor is revving up and has a MAP of 165 ish kpa, could that be the reduction of timing causing reduced power?