Engine Drivetrain 2nd Gen S CEL questions for the smart guys -- Ryefile, Dr O?

Discussion in 'Tuning and Performance' started by paulsminis, Sep 2, 2009.

  1. paulsminis

    paulsminis New Member

    May 5, 2009
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    To those that really know what happens in the ECU,

    History: 2007 R56 daily driver/tracked car. Installed the ALTA turbo back system well over a year ago and experienced no CELs. Roughly a year later I had an RMW tune (I love it), but started getting the dreaded P0420 CEL. Ever since the tune, every time I start the car and drive it, I get the CEL, usually a few miles after start. It's not really a problem as I clear it with the Scan Gauge.

    Now for the reason for this plea: This past weekend I had the car on track at Mid-Ohio. Every time I started the car and drove on my way to the track, I got the CEL and cleared it. However, once I started driving on track, I never got the CEL. Nor have I seen it since, not on the way home, not on my way to and from work the last three days.

    Scratching my head. Any ideas what is going on?

    Thanks,

    Paul
     
  2. goaljnky

    goaljnky New Member

    Apr 7, 2009
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    It fixed itself?
     
  3. paulsminis

    paulsminis New Member

    May 5, 2009
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    Yes, but how did that happen? Is this the new Christine?
     
  4. Nathan

    Nathan Founder

    Mar 30, 2009
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    I'll toss a theory out there....

    P0420 Catalyst System Efficiency Below Threshold

    Running around town the car is rich and fouling the cat. A day at the track cleared it out.
     
  5. paulsminis

    paulsminis New Member

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    That sounds plausible, Nathan. I should then expect to see the CEL after a few/couple of days of street driving, perhaps! Stay tuned!

    Paul
     
  6. Dr Obnxs

    Dr Obnxs New Member

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    Sounds like

    it's in your part throttle tune, or "tip in" compensation, if the Mini has something like that. On the track, you're at much higher load.

    Matt
     
  7. Nitrominis

    Nitrominis Banned

    May 9, 2009
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    #7 Nitrominis, Sep 2, 2009
    Last edited: Sep 7, 2009
    **
     
  8. goaljnky

    goaljnky New Member

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    Comment, or a snide remark?
     
  9. Nitrominis

    Nitrominis Banned

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    #9 Nitrominis, Sep 2, 2009
    Last edited: Sep 7, 2009
    **
     
  10. paulsminis

    paulsminis New Member

    May 5, 2009
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    OK, I named two people (one of whom I have met and talked with) that I really respect and whose postings seem to make good sense to me, and are a heck of lot smarter than I am in hope that they might take a look and offer an opinion. I had no intent to limit input from anyone, nor to imply that there are no other smart folks out there. The description of "smarter than I am" could probably include most folks out there. If anyone took offense, I am sorry.

    In case that isn't clear, anyone is free to comment and help. I appreciate any cogent inputs.

    Dr O -- I appreciate you taking time to answer and you brought up a point I hadn't thought of.

    And, lastly, I have now driven to and from work for the fourth day in a row with no CELs, something that hasn't happened since the tune. Generally my approach on track is to give quick, but gradual throttle input, not mash it to the floor in the vicinity of the apex. And that might just be more indication that it is on tip-in



    Paul
     
  11. Tüls

    Tüls New Member

    Apr 3, 2009
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    derrrrr did yew chek yer blinker flewid
     
  12. btwdriver

    btwdriver New Member

    May 4, 2009
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    +1 for this.

    I also have an R56 with the Alta turbo back. I drove several thousand miles before my first CEL. After I got the first one they come pretty quick. I have also noticed that after driving on the track they don't come back as quickly, but they will come back.

    If I had to guess, guessing now --> I think either the continued higher flow of the exhaust or the sustained increased temperature causes the first cat (the one causing the CEL) to run cleaner and not trip the code. Then after some more DDing the cat gets buildup again and causes the CEL.
     
  13. Nathan

    Nathan Founder

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  14. paulsminis

    paulsminis New Member

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    Absolutely!
     
  15. paulsminis

    paulsminis New Member

    May 5, 2009
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    Thanks for this -- my guess is pretty much the same. Now at 5 days to and from work with no CEL.

    And since you have the Alta Turbo-back and track and have noticed the same thing, I have another quirk I have noticed, and wonder if you have as well: I have a temperature gauge and the scan gauge which both seem to show that once warmed up the temperature is really constant at 220-227 degs F, but when I get the chance to look down after a 30 minute track run, both gauges are showing 190 degs F. That temperature comes back right up to 225 by the time I reach my parking spot in the paddock. If the car's thermostat keeps the car at 225, why wouldn't it keep it at that temp on track? If anything, I would almost expect it to read hotter after a track run, not cooler.

    Paul
     
  16. btwdriver

    btwdriver New Member

    May 4, 2009
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    I have noticed the temp as well. My car seems to run somewhere between 230-240. I have also noticed the fan does not come one until 230, at which point it drops the temp rather quickly, i.e. 236 back to 230. I explained the difference in track temps away to myself as the increase in airflow. Basically doing the same thing as the fan, just manually. I think between that and the increased water flow due to the high average revs you see on a track brings down the temp of the car.

    Really the high revs and increased water flow is the only real difference between the track and driving on the highway. While I do see higher speeds on the track than I do on the highway, they are for such short periods of time I don't think it matters.
     
  17. paulsminis

    paulsminis New Member

    May 5, 2009
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    Thanks for all the great answers to all! I think we have covered it very well.

    Thanks again,

    Paul
     

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