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Thread: Help: Procharged 2016 Corvette REP Mode

  1. #1
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    Help: Procharged 2016 Corvette REP Mode

    Hey Guys,
    I'm trying to help a local shop sort out a couple of projects. One is a 2016 Z06 A8 car. It goes into REP Mode when at high boost/rpm.
    I suspected I would see a P0068 or something of that nature. However, I didn't find any codes.

    I did notice that P0016 had been disabled. I enabled that code and it popped up pretty quickly. It's disabled again now.

    Just a little info on the car. On a good pull, when it doesn't go into REP Mode, it peaks at around 240 kPa. It has a triple nozzle meth kit (3 M15 Nozzles).

    I did notice in this datalog that the Peak and Max engine torque converge under boost. I'll increase Peak and see if that helps the throttle to be more consistent.

    It just seems odd that there is no DTC present when it goes into REP. Will you guys take a look and see what's up?

    Thanks,
    Kevin

    2016corvettez06autoHuntermod.hpt

    z06red4.hpl

  2. #2
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    How is the supercharger inlet pressure and baro sensor set up now?
    Last edited by smokeshow; 07-09-2020 at 03:50 PM.

  3. #3
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    Quote Originally Posted by smokeshow View Post
    How is the supercharger inlet pressure and baro sensor set up now?
    The baro is broke out.

  4. #4
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    Quote Originally Posted by kevin87turbot View Post
    The baro is broke out.
    And what about the SCIAP? Pretty sure I know what the issue is..

  5. #5
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    Quote Originally Posted by smokeshow View Post
    And what about the SCIAP? Pretty sure I know what the issue is..
    That's a good question. I'll try to get a pic of the setup. Do you think the SCIAP is getting a bogus reading and causing an issue?

  6. #6
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    Quote Originally Posted by kevin87turbot View Post
    That's a good question. I'll try to get a pic of the setup. Do you think the SCIAP is getting a bogus reading and causing an issue?
    Well currently it ignores the SCIAP entirely. And with it now looking at the baro sensor as an indication of throttle inlet pressure (TIAP), it's going to be opening a lot more to try to meet a torque request versus how the throttle would open if the ECM was aware there was pressure in front of the throttle. It's either one of two things...the transmission requests throttle closure to meet the torque request for the shift and upon reopening when that throttle torque reduction goes away, desired throttle based on baro moves more quickly back to WOT than the trans was asking for, causing a parallel path calculation fault triggering REP. Or, when the trans requests a throttle reduction during a shift, again the throttle position being based on baro, the position the throttle goes to does not restrict the boost enough and still generates excess torque, causing a throttle flow rationality fault that far exceeds what the P0068 would be looking for and jumps right into REP.

    Either way, it looks like the ECM doesn't trust the TPS feedback because the air that is making it into the manifold based on throttle position voltage is not what it is calibrated to expect. I believe the best way to begin fixing this is to move pressure sensors around and reconfigure the calibration to reflect it. Leave baro reading ambient air, use the old SCIAP and turn it into a TIAP by putting it between the blower and throttle. And set the pressure sensor config to the turbo enumeration...TC-TIAP-TCIAP.

  7. #7
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    Smokeshow, Thank you very much for your guidance. I'll keep you updated on the car.