Speed 6 Tuning Glitch

Discussion in 'Mazdaspeed 3/6 ECU Tuning' started by EdgeAutosport.com, May 12, 2016.

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  1. EdgeAutosport.com

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    So I've been tuning an old friend of mine's speed 6. Car is setup for Aux Fuel (on a 0 map to start). Running a GTX3076, full bolt ons, and a 3.5" HTP intake. Got the MAF cal all dialed in for low load, and then moved on to do some WOT MAF scaling and low and behold, this weird little load spike pops up, accompanied by some crazy AFR's.

    [​IMG]

    No worries, lets make some adjustments to the MAF and see what happens...

    [​IMG]

    Hmm... Well this is annoying. Nothing really changes, and there doesn't appear to be any correlation between between the MAF voltage/Mass Airflow and the load spike. Just the AFR's dipping after the spike.

    After many revisions trying different things like hunting for grounding issues, it became apparent that the load spike was happening in the same place every time regardless of anything else, except for Intake Valve Advance. The only thing that was close to the load spike and was consistent every time was that the intake valve advance went to 0 at the same time.

    [​IMG]

    So, I 0'd out the Intake Valve Advance to see what it would do.

    [​IMG]

    The load spike is still there, but the load kind of spiked up everywhere. At this point, the guy I'm tuning sends me a link he found to MSF, talking about weird AFR's and their relation to intake valve advance. They were also dealing with a load spike. The thread suggested not letting valve advance go to 0 so that's what I did. Set it to taper down to 1 degree.

    [​IMG]

    The valve advance still went to 0 with a target value of one, but it didn't do that till much later in the rpms and the spike moved accordingly with where the valve advance hit 0. So there is the problem I guess. Super frustrating as this is a glitch that has to be worked around, but at least there is a work around.

    So I'm setting the VVT tables to target no less than 2 degrees at WOT.

    Since this was a problem back in 2012, I assume most tuners are aware of it, though it would appear it doesn't effect every speed 6 as this is the first of several that I've tuned to have the problem. So for you speed 6 guys, if you are self tuning and you didn't know already, now you do. Watch out for crazy afr's and a load spike. If you see them, you can fix it by keeping Intake Valve Advance from going to 0 at WOT.
     
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  2. Harvey

    Harvey Greenie Member

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    Maybe this is a VTCS problem?
     
  3. phate

    phate Motorhead Silver Member

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  4. Harvey

    Harvey Greenie Member

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  5. EdgeAutosport.com

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    Yeah, I've tuned a few and this is the first I've seen of it.
     
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