Pulsation when "half-coasting" on Cruise

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by TheLandYacht, Oct 1, 2020.

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  1. wheezyglider

    wheezyglider Active Member

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    I don't have it in front of me but if it helps any you're looking for something like "Fuel System Status" or maybe "FSS". You may need to be connected to the car to find it because the car tells Torque which things it supports. Although Leadfoot is right that this should be a generic PID, ISTR that there is a custom PID with "[PRIUS]" prefix as well.

    edit: a custom PID that is part of the built-in Prius-specific PIDS already included with Torque, to be more clear. You enable those through the main menu settings, extended PID submenu somewhere.
     
    #21 wheezyglider, Mar 20, 2021
    TheLandYacht likes this.
  2. TheLandYacht

    TheLandYacht Member

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    Figured it out & got some screenshots. The stupid tool that tells me a single line of fuel-status info takes up half the damn screen real-estate tho.

    So...the fuel status doesn't seem to have any effect on the symptom.

    And I found a PID that lets me track (count)misfires as they're happening...the problem is, it's not accurate...the count jumps all over the place, random numbers (I even saw negative numbers a couple of times.

    What I DID notice was...as long as I was coasting (like down a hill, or with foot-off-the-gas), or accelerating (like getting up to speed or going up an incline)...that counter stayed at zero (or in a couple of cases single-digits). When in that range I mentioned previously (1500-1800rpm, looks like), it jumps all over the place.

    thumbnail_Screenshot_2021-03-20_220003.jpg thumbnail_Screenshot_2021-03-20_220224.jpg thumbnail_Screenshot_2021-03-20_220418.jpg thumbnail_Screenshot_2021-03-20_220621.jpg thumbnail_Screenshot_2021-03-20_220629.jpg
     
    #22 TheLandYacht, Mar 21, 2021
  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Okay, that's a nice base check. The car isn't screwing up the moment it starts trusting its sensors, so (while not definitive) it sure looks like the ECU is getting good sensor data and reacting appropriately to it. You can discontinue monitoring the fuel system status, but remember where you left it for next time.

    From your detailed misfire results: I'd be looking at this as simple ignition misfire. Maybe try swapping the #4 coil with another cylinder to see if you can make the problem move?
     
    #23 Leadfoot J. McCoalroller, Mar 21, 2021
    Last edited: Mar 21, 2021
  4. TheLandYacht

    TheLandYacht Member

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    Actually took it to the shop last week and they (told me they) did the swap-components-around trick (at least the plug & the coil)...and the symptom stayed with Cyl4.

    The misfire codes are fairly recent (weeks), while the shaking-around thing has been happening since pretty much when I got the car. Although I'll admit the shaking did start getting worse around the time the misfires started happening.

    I've got another thread after I took it to a local shop (non dealer), because they tried to feed me a line about this being the transmission causing a short so I need a new transmission and "we don't work on hybrids beyond simple stuff". Sounded like a cop-out to me, honestly

    I begin to wonder if they lied about swappin stuff around.

    Anyway, as I said (can't remember if it was this thread or that one)...I've actually got an appointment scheduled to get a dealership (the nearest one is like 75 miles away) to look at it a week from Monday (I'll need a loaner while they're lookin' at it & there ain't a rental car in sight this week), I'm just spit-ballin for ideas at this point & hopin for something to fall in my lap.
     
    #24 TheLandYacht, Mar 21, 2021
  5. TheLandYacht

    TheLandYacht Member

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    #25 TheLandYacht, Mar 21, 2021
  6. TheLandYacht

    TheLandYacht Member

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    Didn't end up being the injector either. No change with brand-new injector installed.

    It's at an official Toyota service center now, maybe they can make some sense of this.
     
    #26 TheLandYacht, Apr 2, 2021
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