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Thread: E39 cold start (cat lightoff) disable?

  1. #1
    Potential Tuner
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    Oct 2010
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    E39 cold start (cat lightoff) disable?

    Is there anyway to disable the cold startup (cat lightoff) on the E39 tunes? I've got an LEA 2.4l SIDI ecotec running standalone with no cats, and a very free flowing exhaust. Its not neighbor friendly for the cold morning starts with it enabled. I tried disabling the camshaft cold start enabler, but it seems there's more to it than just that.

  2. #2
    Quote Originally Posted by slammed39 View Post
    Is there anyway to disable the cold startup (cat lightoff) on the E39 tunes? I've got an LEA 2.4l SIDI ecotec running standalone with no cats, and a very free flowing exhaust. Its not neighbor friendly for the cold morning starts with it enabled. I tried disabling the camshaft cold start enabler, but it seems there's more to it than just that.
    cat lightoff in the SIDI uses split pulse injection. They inject more fuel later in the cycle. Look in Fuel -> General, Split (Double) Pulse
    I count sheep in hex...

  3. #3
    if you want to disable cat warmup completely i'll need to add some additional parameters to the editor. Please email support if so.

    Chris...
    I count sheep in hex...

  4. #4
    Potential Tuner
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    Quote Originally Posted by Chris@HPTuners View Post
    if you want to disable cat warmup completely i'll need to add some additional parameters to the editor. Please email support if so.

    Chris...
    Thanks for the reply Chris. I'd love to totally disable it. Emailed support.

    Matt

  5. #5
    ok i added this to all E39's. ENgine -> General, Catalyst Heating, Min ECT & Max ECT. version 2.24.071 or later
    I count sheep in hex...

  6. #6
    Tuner in Training
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    Feb 2010
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    Thanks Chris!
    Over on the Regal boards there are a lot of people complaining about the cat warm up routine causing shaking (myself included) and for others idle stalling.
    Any idea when we can have support for the 2011-2012 Regal turbos with A6? I'd really like to try dissabling the cat warmup to see if that cures the idle issue, or moving it sooner/later in the warm-up cycle.

  7. #7
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    The disable worked perfectly. So, I read up on DI injection and it seems cold start is basically a 'stratified-charge mode' (open throttle, with rpm limited through the injection timing/volume). This DI stuff is pretty interesting. It sounds like the split pulse might be beneficial at high load to help reduce knock. It is disabled in all modes except for cranking in my tune, but the tables are filled in for the high load cells.

    Still trying to figure out why my DFCO will not enable. The torque enablers are confusing, but leaving those alone, it seems like it should hit it at zero pedal.