Ender 3 max with BLTouch won't home anymore

  • Hi

    I have been using my Ender 3 max with BLTouch for several months without issue (I would get the odd BLTouch failure during bed levelling but it was pretty rare). I have the 4.2.2 board. I recently switched to a direct drive extruder setup that maintains the stock fan housing & BLTouch mount and the problems started. There were a few instances of the printer losing it's z position during a print of the first layer ( the nozzle actually lifted a few millimeters off the bed during the print and even buried the nozzle into the bed during another print). The printer would not auto-home. During the auto home, the head would travel to the normal x and y location but the Z would give a firmware error and the printer would need to be reset. During homing the z would move up, the BLTouch would do it's usual thing and deploy the probe, Z would start moving down and usually if the head had to move more that say 30mm, after about 15mm of movement, the BLTouch would magically retract as if it had made contact with the bed (it would not be anywhere near the bed) and then move up and start moving down again to take it's second probe at which point the printer would error out. BLTouch self test, deploy and retract functions work fine. I have re-flashed the firmware and still the same issue. The printer seems to home if the head starts out close to the bed but if it has any sort of distance to travel, it errors out. I have unplugged the BLTouch, re-flashed to the original firmware and plugged back in the z-stop and the printer works fine.

  • @Davethegearhead

    Could this BL touch problem be the wiring to the sensor or it’s plug connector? I had a problem after I decided to tidy up the wiring on my Ender 3 by neatly cable tying the hot end. When the Z moved it pulled on the wires and caused erratic BL touch functions.
    Also has the Z limit switch been removed?

  • If you found a fix please post. I'm looking for one as well. I'm using a CR Touch but have essentially the same issue. I've got my CR Touch plugged into the 5 pin connector. For now I've actually just flashed firmware to disable the bed leveling, which is driving me nuts because now I can't have my wife swap beds while I'm at work then start a new print remotely as the beds are just different enough to make prints fail.

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