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hv discharge 70 mph

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by joyrider300k, Jan 15, 2014.

  1. joyrider300k

    joyrider300k Junior Member

    Joined:
    Jan 15, 2014
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    Vehicle:
    2005 Prius
    Model:
    Two
    Early 3/05 prius 276k, mobile 1, regular transaxle oil changes, never overheated, wrecked, mice damage or submerged. Just replaced leaking cat exhaust dougnut, but exhaust is still seeping in cabin if ac not recirculate. (the cat may be plugged from excess fuel)
    1 traction cell shorted 4 months ago, limped home 40 miles.
    Rebuilt and balanced pack, no issues from this.
    Battery cells 0.18 ohms each and 16+ volts each, a deep cycle battery is in parallel with the aux for testing.
    Car runs fine 40+ mpg (at 0-20 F) when driving less than 65 mph (soc stays in the middle)
    Above 65 mph soc gets lower and lower (will not charge) and at 1 bar soc engine rpm goes way up.
    No lights on dash, intelligent tester and scangage report no issues, swapped a good 04 inv-conv, 04 battery ecu, o4 engine ecu, 05 hybrid ecu one at a time without help.
    All 3 windings of mg1 and 2 have continuity and isolated from ground.
    Car rolls fine, maintains speed as before, mg1 and 2 rpm are reading.
    I am an electrical engineer, have read factory manual cover to cover.
    There are no relevant posts on Prius chat.
    Does anybody have experience with this issue?
    What am I missing? Could she just be on her last leg?
    This is making me nuts, thank you for the input.
     
    #1 joyrider300k, Jan 15, 2014
  2. PriusInParadise

    PriusInParadise Member

    Joined:
    May 24, 2012
    180
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    Location:
    Hawaii
    Vehicle:
    2011 Prius
    Model:
    Two
    Sounds like the gasoline engine is not producing enough power to propel the car at freeway speeds. The HV battery is being discharged while trying to assist in propulsion. You mention that the cat converter may be plugged up. You're probably right that there may be an exhaust restriction. That would certainly reduce the engine's output. There can be a significant exhaust restriction without any DTC being set.
     
    #2 PriusInParadise, Jan 15, 2014
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,200
    6,479
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    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    I agree that the catalytic converter may be restricting power output. Or, the gasoline engine may be worn and not be performing. At 276K miles, it has served way beyond the call of duty.

    So, if you want to restore the vehicle to proper operation, first try replacing the catalytic converter. If that doesn't help, install a used engine from a salvage yard.
     
    #3 Patrick Wong, Jan 15, 2014
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