Potential boost leak? Negative fuel trims

Discussion in 'Mazdaspeed 3 Troubleshooting' started by Ms3orDie, Jun 2, 2021.

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  1. Ms3orDie

    Ms3orDie Greenie Member

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    Im trying to chase a potential boost leak and I think ive exhausted all my options here. Boost leak tested and found nothing. Tuned for 25 psi but im only getting 14-16 at wot. Rarely i get 19-20 but only during certain conditions. My ltft is at -9.52 and stft is at -3.28 at idle. At wot, they both go to -0.16. Only cel i have is for my deleted egr and tpms.

    Recent work done:
    Valve cleaning
    Injectors flow tested
    Injector CS seals
    EGR Full Delete
    PCV plate and valve
    VTA Oil Catch Can
    New Intake Manifold gasket
    New Throttle Body gasket

    But even prior to this i had a potential leak and fuel trims were worse on the negative side. About -15 for long and short term was sporadic anywhere from 4 to -14. Recent work definitely helped the fuel trims. Through the ap, i see that my evap system is not ready. Unsure if this has anything to do with it. Any ideas? Tia.
     
    Ms3orDie, via an iPhone, Jun 2, 2021
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  2. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    Fix the eval system it's throwing off the trims
     
    Easter Bunny, via a mobile device, Jun 2, 2021
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  3. Ms3orDie

    Ms3orDie Greenie Member

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    Wouldnt a bad evap system throw a code?

    Edit: i get what you mean now. Ill need to do a drive cycle to get systems ready. But damn i put at least over 100 miles on it since the recent work
     
    Last edited: Jun 2, 2021
    Ms3orDie, via an iPhone, Jun 2, 2021
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  4. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    Is the code for the eval turned off in your tune?
     
    Easter Bunny, via a mobile device, Jun 2, 2021
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  5. Ms3orDie

    Ms3orDie Greenie Member

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    No
     
    Ms3orDie, via an iPhone, Jun 2, 2021
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  6. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    It should only be throwing off your trims if it isn't working correctly if it's just not ready them it should be fine
     
    Easter Bunny, via a mobile device, Jun 2, 2021
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  7. Ms3orDie

    Ms3orDie Greenie Member

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    Ok. So then my issue lies elsewhere.
     
    Ms3orDie, via an iPhone, Jun 2, 2021
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  8. broda

    broda Greenie Member

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    What PSI did you boost leak up to?
     
  9. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    Is your air filter really dirty?
     
    Last edited: Jun 3, 2021
    Easter Bunny, via a mobile device, Jun 2, 2021
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  10. Ms3orDie

    Ms3orDie Greenie Member

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    Ms3orDie, via an iPhone, Jun 2, 2021
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  11. Ms3orDie

    Ms3orDie Greenie Member

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    Really what?
     
    Ms3orDie, via an iPhone, Jun 2, 2021
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  12. Easter Bunny

    Easter Bunny Professional Engineer Motorhead Platinum Member

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    Dirty
     
    Easter Bunny, via a mobile device, Jun 3, 2021
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  13. Ms3orDie

    Ms3orDie Greenie Member

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    Ms3orDie, via an iPhone, Jun 3, 2021
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  14. Ms3orDie

    Ms3orDie Greenie Member

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    Stupid question but, i tried doing a boost leak test on the intake side and air is escaping from my vta cc. Could this be causing the leak? I have a brand new pcv valve and the check valve that damond supplied.
     
    Ms3orDie, via an iPhone, Jun 3, 2021
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  15. broda

    broda Greenie Member

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    That's a fairly large boost leak, so yes. Is there a chance that the check valve between the IM port and the OCC is backwards? Or did it happen randomly after having it installed for a while.
     
    broda, via a mobile device, Jun 3, 2021
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  16. Ms3orDie

    Ms3orDie Greenie Member

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    So when i purchased the occ from damond, the hose already had the check valve pre-installed. I didnt bother to check it.
     
    Ms3orDie, via an iPhone, Jun 3, 2021
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  17. broda

    broda Greenie Member

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    That'd be the best thing to double check. You're naturally going to leak a small amount of pressure into the crankcase because of putting air into the cylinders so that'll go through the PCV into the OCC. You could just be seeing that but if it's a significant amount of air then it's likely to be that check valve.
     
    broda, via a mobile device, Jun 3, 2021
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  18. 07mspd3

    07mspd3 Greenie N00B Member

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    Did you ever resolve your issue? I’m having the same symptoms
     
    07mspd3, via an iPhone, Oct 21, 2021
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