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  1. #1
    Member
    Join Date
    Jan 2008
    Location
    Angier, NC
    Posts
    852

    Is this TRUE….

    I have been told, If you lay your foot on the throttle of a 250 FS while starting the motor, the electronics will only give you 90% of throttle response. Is this a bunch of crap that someone has made up to protect the innocent? Is this true?

  2. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,941
    #2
    Actually- only PARTIALLY true.

    If you lay your foot on the throttle while turning the key on, or while starting the engine, the PCM attempts to learn the throttle position and cannot accurately determine the IDLE position. Consequently, one of the following is likely to occur:

    -PCM inaccurately learns idle, and thus inaccurately computes WOT position

    -PCM cannot adapt the Idle Position because the reading is outside of the acceptable range of parameters (resulting in Guardian and limited available power)

    -PCM adapts to what it "thinks" to be idle if it IS within acceptable range: But when you release the hotfoot and it returns to the stop, the PCM logs either a Demand Sensor Fault, OR a Mal-Adapt Fault (because it's impossible for the TPS to fall BELOW idle under normal circumstances). This also results in Guardian being active.

    If you would, please take a moment to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting (as well as the other guidelines). Thanks!


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