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Thread: AE vs MAP difference

  1. #1
    Fuel Injected!
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    AE vs MAP difference

    I sometimes get knock counts while at steady state throttle when the van shifts into O/D, I was thinking of playing with the AE vs MAP difference table as I can see some brief AE activity when it changes gear, presumably caused by the increase in MAP.
    I'm assuming the values shown in the table are microseconds and to increase fuel delivery I should look at increasing those microsecond values?
    Does changing those values increase the AE fuel delivery duration, amount of fuel delivered or both?
    I've been searching but haven't really found a good clear explanation of how those values impact the AE fuel delivery (well clear to me).

  2. #2
    Fuel Injected! brian617's Avatar
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    Quote Originally Posted by Kitch View Post
    I'm assuming the values shown in the table are microseconds and to increase fuel delivery I should look at increasing those microsecond values?
    Does changing those values increase the AE fuel delivery duration, amount of fuel delivered or both?
    Increasing the AE value increases the PW (Pulse Width) of the injector. The fuel pressure is fixed so the duration of the PW determines the amount of fuel injected per event.
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  3. #3
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    Thanks for the reply.
    In closed loop should I be able to watch my wideband readings and see an AFR change when MAP instigated AE is active or will AE be limited by closed loops stoichiometric requirements?

  4. #4
    Fuel Injected! brian617's Avatar
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    I see AE on my wideband, even if just small amounts, open or closed loop.
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
    95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
    05 Outback XT 2.5L turbo gas auto

  5. #5
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    I see AE or lack of AE in closed or open loop without a wideband using the OEM narrow band(s). In closed loop too much AE will drive the INT or Short Term fuel trims negative. Too little will cause the INT or Short Terms to rise. In open and closed loop it will cause the o2 voltage to change.
    Last edited by Fast355; 10-08-2018 at 05:41 PM.

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