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Thread: Purge solenoid ignoring speed and airflow limits

  1. #1
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    Apr 2010
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    Default Purge solenoid ignoring speed and airflow limits

    While I was doing some idle tuning I noticed the purge solenoid was opening and adding unwanted air. For some reason only the min temp value B0501 is operational. Anything I set B0502 and B0503 seems to have no function which I need to prevent it from opening when stationary at idle. Has anyone come across this issue and found a workaround? I have tried a full flash and still no luck. Engine is an LQ4 with 1MB LS1B green & blue connector PCM. Running COS 3150003. The solenoid is definitely working as the temp parameter does control it.

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    Last edited by ttls1; May 16th, 2026 at 10:35 AM.

  2. #2
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    Jun 2026
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    I found the debate on the purge solenoid that ignores speed and airflow limits fascinating! As someone who has dabbled in tuning and diagnostics, I understand how frustrating it is when systems fail to behave as intended. It is critical to consider how these components interact with overall engine performance; neglecting these restrictions might skew data and result in inefficiencies.
    Last edited by obesewhistle; 2 Weeks Ago at 03:34 PM.
    LQ4 with 1MB LS1B sprunki game

  3. #3
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    What I have had to do is install a frequency switch that references the vss. At speeds under 20kph it opens a relay which disconnects it from the pcm. It would have been nice if the parameter worked in the software as its was a bit of work and unnecessary butchering of the harness.

  4. #4
    Lifetime Member
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    Mar 2006
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    Default

    Its easier to just unplug the solenoid connector.

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