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question about open loop

Discussion in 'Forced Induction' started by johnboi85, Nov 29, 2009.

  1. johnboi85

    johnboi85 Well-Known Member

    what rpm at low load does the computer switch from closed loop to open loop? and what throttle percent does it switch from closed loop to open loop? car is an 88 st165. thanks
     
  2. Celic_GT2

    Celic_GT2 Well-Known Member Moderator Donated!

    its by temp, at first it reads pre determined settings in the ecu,(open loop) once warmed up it reads off all the sensors (closed loop)
     
  3. Mafix

    Mafix Owner Staff Member Administrator Donated!

    you sure about that. i thought it was only open if the check engine light came on.
     
  4. Celic_GT2

    Celic_GT2 Well-Known Member Moderator Donated!

    Open loop:
    An operating condition or mode based on programmed instructions and not modified by a feedback system
    A predetermined operating condition not based on exhaust gas conditions

    Closed loop mode:
    Once the engine has reached warm-up temperature, the engine management computer collects the precise data from all the sensors (coolant temperature sensor, throttle position sensor, oxygen sensor, etc.) to determine the most efficient air/fuel mixture for combustion.

    straight from my college textbooks.
     
  5. johnboi85

    johnboi85 Well-Known Member

    yes it does run in open loop on a cold start up until it reaches temp. then it will go into closed loop. what i'm looking for is when it switches to open loop such as when going full throttle. there has to be a certain throttle percentage that it will switch to open loop. also, it should switch to open loop at a given rpm even in low load.
     
  6. Mafix

    Mafix Owner Staff Member Administrator Donated!

    oh the 165 ecu has 2 modes. normal and race
     

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