Pixhawk motor issue

hi have a pixhawk on my quad and ive been though the setup 4 or 5 times now and still end up with the exact same issue now. I have done a compassmot motorsync and rc cali and everything else needed. running the latest firmware ie 3.1.5 and have changed that also to older firmware with no difference. All I get it is when its armed the 2 front motors spin and the rears don't. When I increase the throttle the rears kick in and the whole model shakes like mental. I have a video here of the problem:


Really need this issue sorted as all my model stuff is up for sale. thanks austin

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  • Maciej many thanks goes to you for your help and advice. the video u did was perfect. all sorted I am happy again lol. thanks to all for chipping in too.......

  • Youtube shows that your video is private.  If you want it viewed, you'll have to fix that.

  • when I use the terminal and go to motorsyne the motors work fine and correctly. but when I disconnect and try to fly its shakes quite badly. listen to the audio in the video. all Ihave done it remove pixhawk put it on a trad heli and then back to quad. had no crashes at all. nothing has changed just installed firmware and reset up. but now this issue. ill check the motors and esc separately but im not sure wot the problem is.

    • That is why you need to systematically debug the problem. 

      Sorry but that is how this stuff works.

      Take care,


    • Moderator


      These guys are giving you good advice. You need to take a step by step approach to determine the problem. Take a step back and start again. What king of Quad is this and what ESCs are you using, are they flashed with SimonK firmware? When you run the ESC calibration, are you using the All at once method or are you doing one ESC at a time? It sounds to me like you need to do the One at a time method.

      BTW as Maciej mentioned in the first post, we can't view your video because you have it posted as private. Please post a new link to a public video so we can see the behavior for ourselves. Also including a logfile would help.


      Nathaniel ~KD2DEY

  • Try testing each esc + motor separately and then if they all work correctly then test the quad again. If you have the problem then retreat the esc connections on the flight controller and see if the problem follows the  swapped hardware or remains. You should be able to isolate the issue. 

    Take care,


  • What do you mean with motorsync? Is that ESC calibration or something else? I had similar issues before I calibrated my ESCs


    Your video is by the way private so I cannot see it.

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    • Hi you are a life saver this has totally cured the problem 100% and now fully working as should be. didn't know u had to do this and never had done this b4. again many thanks austin.

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