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Bad stumble on 328 -- only on the track

Discussion in 'Technical Q&A' started by GrigioGuy, Dec 7, 2003.

  1. GrigioGuy

    GrigioGuy Splenda Daddy
    Global Moderator Owner

    Nov 26, 2001
    23,028
    E ' ' '/ F
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    Yes, I have one
    I took a performance driving course this weekend (more on it later) and found something odd. The final exercise is several runs through a mile long road course that is all curves. My 328 was suffering from very bad stumbling during this course.

    Here's what I know:

    1. In ordinary street driving, I don't have these problems. Full throttle means full power, no stumble. I drove it 400 miles this weekend without issues.
    2. What I was seeing on the track was that I'd hit the gas out of a corner, and the engine would almost die for a few tenths and then roar into full power.
    3. The gear selection didn't matter
    4. The gas tanks were full during these times.
    5. I had no problems anywhere else during the weekend.
    6. The problem happened on both left and right turns. Seems like it was worse on sharper corners, but I could have been handling the gas differently on the sweepers

    Thoughts? I know I lost a lot of time with the way it felt.
     
  2. ferrarifixer

    ferrarifixer F1 Veteran
    BANNED

    Jul 22, 2003
    8,520
    Melbourne
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    Phil Hughes
    A very lean mixture will cause the engine to have a big gulp of air. Backing off and progressively re-applying the throttle will usually see it ok again.

    If this is the case, get the tune checked and adjusted.

    Be sure to use high octane fuel wherever possible, but especially on track.

    Check for loose air hoses, or dirty air filter.

    It's also possible you have a bad connection to the engine somewhere...usually where the multi plugs that connect the crank sensors and other engine loom parts connect to the chassis near the oil cooler at the top....check under the bonnet and inside the left hand wheel arch.
     
  3. GrigioGuy

    GrigioGuy Splenda Daddy
    Global Moderator Owner

    Nov 26, 2001
    23,028
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    That was the diagnosis by my local mechanic too. It just was tuned to get through emissions and I'm sure it went lean then.
     
  4. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    2,558
    Chicago
    Full Name:
    Philip
    Phil
    I had heard this problem with the carb'd cars starving for fuel on aggressive and sustained cornering, not FI. Common issue?
    Philip
     

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