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E-CVT brushes / magnetic clutch not functioning.

Discussion in 'Subaru Sambar' started by dcur, Feb 18, 2013.

  1. dcur

    dcur New Member

    Hello,

    Picked up a 1990 Sambar, e-CVT and supercharged. Trans was slipping and grinding badly. Barely made it home. Swapped out the fluid which got rid of the grinding noise. Old fluid was burned and dark. Clutch is still not engaging however. I did some quick math and jumped the electro-magnetic clutch with a resistor to supply correct amperage as if throttle were WOT. The Sambar jumped forward.

    This is telling me the issue appears to be with the control circuit. Not supplying anything to the clutch really. Before tearing into the electrics I wanted to check the basic stuff. Heard the brushes can cause problems. Tonight, I removed the airbox and starter and pulled the brush holder out. The brushes look mint. No corrosion and they appear to have significant length left. However, during my removal, I found a plug with exposed copper wire that appears to have been shorting out. This looks as if it goes back to the speed sensor VSS on top of the trans/diff. I do see a mechanical cable porting out of the trans / diff that I'm assuming goes back to run the speedo.

    Going forward I believe there are 2 things that affect the clutch engagement electrically. VSS and throttle position. Possibly engine rpm but most likely not. The accelerator switch seems to just enable the circuit, leaving the clutch minimally engaged until vehicle speed AND throttle position increase.

    Here are my questions:

    - Are the brushes of optimal length? There appear to be wear indicators but I'm unsure of how to read these. I'm assuming if you can see them, the brushes are okay.
    - Is the plug I have located with exposed wire indeed for the VSS back to ECU?
    - Is the sensor outlined in the pictures actually the electric VSS?
    - Where is the ECU / TCU? I would like to trace the clutch wiring back to the ecu and test for faults. I've looked under the driver seat and around / under dash area / under console. Can't locate.
    - Am I correct in assuming if the ECU sees 0km/h the clutch will never begin to engage more than the lowest 'starting' engagement?
    - Am I correct in assuming the speedo can still function (being mechanical) while the VSS is toast?
    - What resistance should the e/m clutch be? I was measuring 50-70 ohms.

    Any help would be appreciated.
    Coming to ya from Victoria, BC. Thanks.

    dcur

    IMG_0066.jpg IMG_0065.jpg IMG_0061.jpg IMG_0048.jpg IMG_0059.jpg
     
  2. spaner

    spaner Well-Known Member

    Obviously that's not your problem.

    Burnt fluid = burn clutches...yea?

    Rebuild.

    Take pics and post, cu'z we appreciate that.
     
  3. LAZ 1

    LAZ 1 New Member

    I also have a 92 Sambar which has the ECVT trans and supercharger, and 98 K on it.
    When I bought my van I also bought the Subaru English language shop manual.
    Unfortunately the manual shows details for only the standard trans, NOTHING for the E-CVT.
    [;{(

    Subaru seems to really like the E-CVT system and has been using it on several of their vehicles, including some of their new builds. I would have preferred a standard trans for my Sambar, but could only find an E-CVT model.
    So far, I have had no real issues with the trans. Only complainbt is that my gas mileage isn't the best ...
    but then I have 175/70/R 13" tires on mine.

    I live on Gabriola Island and get down to Victoria almost every week.
    Maybe we should meet and compare vans??

    Comparing the non-working unit with a working unit is some times useful for trouble shooting ANYTHING!
    You might see something on my van, which is WORKING PERFECTLY, that is different on your van?

    You can private message me if you want to go meet up to compare vans.
    Other wise, good luck ...
    LAZ 1
     
  4. spaner

    spaner Well-Known Member

    Very nice,
    Probably you should just give Todd a call @ minitruck.ca, and get a fix and/or a manual 5-speed for your van.

    Fixed and done.
    He's got a lot of wrecks in the yard and could probably hook you up with something used-and-cheep.
    Maybe, just saying...
     
  5. LAZ 1

    LAZ 1 New Member

    Found this info in another thread,
    The ECVT brushes need to be replaced every 25 K kms. Remove the starter and remove the two screws in the plate under the starter. Lift the assembly out and check length of the brushes. Lines are scribed with about ½” between the line and the tip when new. If worn down to line, time for new brushes.
     
  6. dcur

    dcur New Member

    @spaner

    "Burnt fluid = burn clutches...yea?"

    Not sure this is the case. The clutch is not immediately involved with the hydraulics in the trans. It's external and consists of copper windings and ferrous powder. When they burn out they just don't work. I'm able to jump the clutch and it will lock up. Leading me to believe there is an issue with the control circuit.

    "Take pics and post, cu'z we appreciate that."

    The pictures should be on the bottom of my initial post. I think you have to be signed in to see them.

    "Probably you should just give Todd a call @ minitruck.ca, and get a fix and/or a manual 5-speed for your van."

    Thanks for the suggestion. I would like to try to diagnose and resolve the issue myself if possible with the current parts at hand. Barring that I probably will take a trip up there and see what he's got for 5-speed swap parts.


    @LAZ 1

    "Found this info in another thread,
    The ECVT brushes need to be replaced every 25 K kms. Remove the starter and remove the two screws in the plate under the starter. Lift the assembly out and check length of the brushes. Lines are scribed with about ½” between the line and the tip when new. If worn down to line, time for new brushes."

    Thanks for that, I think I've seen that thread. The only thing is that my brushes look mint! The picture should be under my initial post. Looks as if they're almost brand new to be honest. And on top of that if I give the brushes 12v the clutch will lock up. I've read another thread that suggests to remove the brushes and file in a small diagonal groove in them which should direct any oil/debris off the slip ring. I will try this as soon as the weather lightens up.


    If anyone has any electrical insight I could mention this. The clutch resistance when not in motion is very low which is a good thing. As the RPM increases the resistance of the clutch increases. I believe this is the reason for the trouble. As RPM increases the CTU is trying to increase voltage / current to the clutch. Because the clutch resistance is going up it's not engaging correctly and also tripping the CVT-clutch lamp on the dash. As mentioned, I may try to groove the brushes, if that fails I will replace the brushes and springs and see what happens.

    Thanks for the input.
     
  7. LobeyWan

    LobeyWan New Member

    i know this is old but did you ever find the problem with this?
    i am experiencing similar, i can drive, but when travelling up hill (and when the car has warmed up maybe??) the more i seem to accelerate the slower i go, if i take it easy i seem to maintain a steady SLOW speed (20km)
    its as if the clutch is not grabbing 100% its does not seem to be a fuel issue at all
    i have tested the clutch with a 9 volt battery (spin the "stalk") and when applying the battery to the rings it locks up
     

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