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Loss of electrical power/reset on startup.

Discussion in 'Technical Chat' started by MGRS, Sep 17, 2009.

  1. Sep 17, 2009 at 9:24 PM
    #1
    MGRS

    MGRS [OP] Well-Known Member

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    I have a very strange and very intermittent problem that is also very irritating. The last time it happened before today was four weeks ago.

    Description:

    Accelerating from a stop, not lugging the motor or anything other than normal, I lose electrical power for <1 second. Dash lights, head lights, clock, radio, everything. It all goes out and then comes back on. Truck then acts like nothing out of the ordinary happened.

    The next time the motor is started, the clock is reset, seat belt chime is reset, and the truck idles at 2K no matter how warm it is. Every time you take it back out of gear, idle rises to 2K.

    I turn the truck off, back on again, and the idle is down to 1.5K, but will go no lower until I put 10 miles on the clock, at which point everything returns to normal.

    Vehicle:
    '08 Tacoma V6 6spd 4WD
    I have installed a Yaesu radio. It is wired directly via ring terminals to the battery clamp bolts and there are no shorts/exposed wire in the system. Installation was done to radio manual instructions. The truck also did this once before the radio was in.

    The dealership says they can do nothing unless I can reproduce the problem for them (I can't).

    I have an appt. with service saturday to fix (2nd try) the leaky diff drain seal (service manual spec torque, new gasket and plug, still leaks about 1qt/2 weeks).

    Frustrating....
     
  2. Sep 18, 2009 at 5:54 PM
    #2
    EnolaGaia

    EnolaGaia Well-Known Member

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    When you get a power drop-out while driving, doesn't the clock reset then? Or are you meaning that the clock only resets after turning off the ignition after one of these drop-out incidents occurs?

    The 'next time the motor is started' symptoms are all consistent with a total power loss. The odd engine behavior sounds like a 'brain dead' ECM having to 're-learn'.

    The part that baffles me is (assuming I'm interpreting it correctly ...) why these behaviors don't happen until the next time the truck is started ...
     
  3. Sep 18, 2009 at 6:24 PM
    #3
    98tacoma27

    98tacoma27 :POOPCORN: Staff Member

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    It sounds as though there may be a loose connection some where, either ground or a B+ connection. I would start at the battery just for posterity's sake. Being it's an 08 I don't think that is the issue but it is worth a try. My second suggestion would be to inspect the connections on the ECU. There is one B+ supply to the ECU however it splits into to connections on the ECU. Without knowing the circuitry of the ECU itself, it may be plausable that one of those connections is loose enough to only fail continuity at certain/random times. This is purely speculation but the B+ being split into two terminals suggests that it supplies two different internal circuits on the ECU.

    This is the only thing I can come up with without actually saying the ECU is bad. It is located behind and above the glove box if you wish to investigate. It also would hurt to inspect fuses.
     
  4. Sep 18, 2009 at 6:47 PM
    #4
    MGRS

    MGRS [OP] Well-Known Member

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    Thanks for the response.

    I worded my OP poorly. The clock goes back to 12:00 immediately. The high idle does not show up until the next start.
     
  5. Sep 18, 2009 at 6:50 PM
    #5
    MyToyTaco

    MyToyTaco ╒╪╕

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    have you done any electrical mods?

    edit- other than the radio
     
  6. Sep 18, 2009 at 7:46 PM
    #6
    MGRS

    MGRS [OP] Well-Known Member

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    None. I would have thought the radio could be to blame, but it is connected to nothing but the battery.
     
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