How come motorcycle EFI's are open-loop??
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Thread: How come motorcycle EFI's are open-loop??

  1. #1
    Greeneyes
    Guest

    How come motorcycle EFI's are open-loop??

    If i understand correct, open loop=pre-programmed ecu mapping,varies pulse width depending on gear/rpm or load and rpm/gear or something of that sorts. as opposed to closed loop, with an o2 sensor that sends feedback to the computer about fuel mixture and computer adjusts as nessesary.
    Why do bikes use open loop????? wouldnt it make sence to use 02 sensors like cars use?it would once and for all solve lean-problems due to a fancy pipe/air filter, without need for a Power commander and also altitude changes.

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  3. #2
    Registered User Array jonesboy's Avatar
    Join Date
    Mar 2002
    Location
    New West
    Bike
    '09 Bandit SEA
    Closed-loop systems don't react quickly enough to changes to be used in lieu of pre-programmed maps- the O2 sensor is mostly useful for adjusting AFR while crusing on the highway or in other situations where the parameters don't change much (the mixture is leaned out slightly to conserve fuel).

    Cars need to have fuel maps changed when modifications are done as well, many closed-loop EFI systems ignore O2 sensor feedback during accelleration, for example. O2 sensors just aren't that useful to us, for the most part (although for big touring bikes they are - and BMW's EFI system is closed loop, I believe).

    -Matt

  4. #3
    Registered User Array Chumly's Avatar
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    Jun 2004
    Location
    Vancouver
    Bike
    Honda & Suzuki
    My VFR VTEC is closed at least for steady state part throttle, and it causes lean surging. Bike EFI has quite a ways to go before it can equal car EFI.

  5. #4
    Liquid72
    Guest
    They are hand cuffed by the emissions laws in north america as well...so Im sure the bikes are tuned on the lean side.

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