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Bad ECVT clutch? Bad ECVT clutch controller?

Discussion in 'Subaru Sambar' started by Matt Rooney, Jun 29, 2022.

  1. Matt Rooney

    Matt Rooney New Member

    Hello all,

    New to kei trucks and new to the forums!

    Been having some issues with my 95 automatic supercharged Sambar.

    When the engine is running and the vehicle is at a standstill, it is difficult to shift out of neutral into either forward or reverse. Occasionally this is coupled with the sound of gears grinding. These symptoms make me think that perhaps the powder clutch is not fully engaged.

    Once in drive, the car seems to drive just fine. However, after parking and getting out, the smell of clutch is pretty apparent. This makes me think that the clutch is not fully disengaged when driving about. If driving for more than a few miles, the car will sometime shut off if I come to a complete stop and the "clutch temp" light will come on. When this happens the car can be restarted without issue, but it's nerve wracking nonetheless.

    I have ordered new brushes for the clutch. The ones that I pulled out unfortunately look like they are in fairly good condition so I'm not sure that is the problem. I think my next step may be the replaceme the powder clutch itself.... But I'm hoping there might be an easier solution. Bad anybody encountered a problem like this and if so, how did you go about solving it?

    Thanks!
     
  2. Matt Rooney

    Matt Rooney New Member

    Took out the old brushes for the ECVT and thought they looked okay... went ahead and ordered a new set for 60 bucks as a shot in the dark. Replacing the brushes in my case made no change.

    Found an old guide for the EVCT in a Justy... very similar but not exactly the same... the Justy has two switches attached to it's throttle pedal, an "Accelerator Switch" and a "Throttle Position Switch" My Sambar only has one of these switches... and I'm guessing it is the Accelerator switch.

    Quote from the old Justy EVCT guide
    "The the accelerator switch is stuck or held open (no current) the vehicle will creep immediately when the transmission is placed in gear. It will also be difficult to shift out of gear and when shifting through "NEUTRAL." It may be accompanied by a grinding noise. In this situation, the CCU does not recognize a problem. Therefore, the Check Light will not illuminate an no code is stored in memory. However it can be easily checked with the select Monitor by using Mode FA1 and observing LED#9.

    These are pretty much the exact issues I am having. I unplugged the throttle petal from the main harness and was able to verify that the switch in the throttle IS functioning. I connected the two ends of main harness to the pedal unit with a piece of wire and there was no change. For these reasons, I am thinking I have an interruption to the Accelerator Switch circuit somewhere other than the Accelerator Switch itself... where I'm not sure. i'm not sure where there are other easily accessible plugs for this circuit that i can check. Maybe somewhere back at the ECVT? or the Clutch Control Unit?

    Thanks for reading and if you have any ideas, Please let me know!
     
  3. Jelly

    Jelly New Member

    I have no idea, ECVT gives me headaches. I'm waiting to have a rebuild ECCVT sent since no one wants to work on it in my area.
     
  4. willoh

    willoh New Member

    "Erik asked about how the powder clutch works so here's an explanation, as well as how to buy an ecvt Sambar
    How come some ECVT Sambars reach well over 120k km on the original powder clutch, while others fail as low as 30k km?(average seems to be at 60-80k km).
    The short answer appears to be driving conditions and driving style; every time you engage/disengage the clutch, you decrease the life of the powder. Same with accelerating or braking abruptly.
    So an ecvt van imported from a rural area with no stop lights and easy traffic and minimal load/granny driver will last much longer than a van or truck coming from a hilly urban area with lots of stop and go traffic.
    For the long answer, read below.
    For a simplified visual model of the powder clutch, imagine two vertical, parallel disks with a gap in between. The gap is filled with some black iron powder. One disk is the driver half (connected to engine); the other is driven half (connected to transmission).
    When magnetized, the tiny powder particles bind together and bridge the gap solid, transferring motion/torque from the driver half to the driven half.
    There is momentary slippage when the two halves start engaging or disengaging. Various degrees of slippage are necessary to prevent abrupt transmission of power at take off, or engine stall when braking, or hill start roll back.
    But slippage comes with a big drawback: overtime, that momentary friction grinds down the particles, and the powder can no longer bind properly.
    To compensate for reduced particle size, the ecvt ECU should adjust the magnetization over time. But it doesn't, because it's only calibrated for normal sized particles.
    As the clutch starts slipping for longer periods of time, extra heat is generated, quantified as clutch temp light.
    It gets even worse when the particles become small enough to escape the clutch; that's why the bell housing interior ends up coated with dust, turned red from oxidation. At this point the vehicle stops moving altogether.
    Conclusion: the powder clutch does not wear when fully engaged, only when starting and stopping. The brushes however, wear constantly while driving.
    Worn or oily brushes cause slipping. So before replacing the clutch, always check the brushes.
    A faulty charging system or poor connections can also cause slippage, as the clutch is not energized enough.
    So how to buy an ecvt Sambar?
    70% of the respondents to my ecvt failure survey experienced clutch failure; a couple of them while being picked up from the port, and the majority occurring within the first year in the US.
    The first line of ecvt defense at japanese auctions would be buying very low mileage. Good luck with that.
    Next, an inspection before auction if possible, to avoid complete duds.
    And ideally, replace the brushes, clutch, ecvt fluid and filter while still in Japan (MKT Japan is providing both inspection and parts replacement services).
    When buying a vehicle already in the US, assume that you will need to replace the brushes and clutch, and stock up on them as they are still available new. If you lack the necessary skills, have a mechanic lined up (i.e Todd Oldenburg)
    Take a looong test drive and watch for these symptoms:
    shifter hard to move from P/R
    creep (unlike regular automatics, ecvt does NOT creep when in D)
    engine revs but weak or no acceleration
    slips or stops moving when warmed up
    delayed ecvt response when pressing the gas pedal, followed by jerky engagement
    engine stall and/or tire lock when braking or at low speed
    whining, intermittent clonking or unusual noises

    Note 1: at this time it is unclear if whine is clutch or hydraulics related (video in comments)
    Note 2: the above symptoms were compiled from the Hatenablog ecvt complaints (link in comments)
    Disclaimer: while the majority of ecvt issues are brush and clutch related, we had a case of hydraulic system failure, and a broken steel belt. Our Sambars are 3 decade old vehicles so anything is possible.
    Also, when ordering a powder clutch, check our spreadsheet for the correct part number, and even then, cross it with your VIN especially if you have a '95
     
  5. Matt Rooney

    Matt Rooney New Member

    Wow! Thank you for that information! Super helpfull
     

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