From day one I was getting AMS motor overload errors, and on top of that I was dealing with a poop-clog issue. I think I’ve finally solved both problems with help from Bambu support and the community. Hopefully this helps someone else diagnose their issues.
AMS Motor Overload Issue
As you can see in the pictures, my setup isn’t great, and I plan to fix it soon.
The cause of the AMS motor overload error was that the pre-installed PTFE tube from the buffer to the toolhead was too short. When printing at max bed size while using a 4-way hub, it created too much friction and triggered the overload error. After I replaced the tubing from the buffer to the toolhead, the issue got better but didn’t fully disappear. I then added a nylon cable tie (shown in the pictures), and now I can’t reproduce the problem at all.
Poop Clog Issue
I also noticed that the poop chute would get clogged and back up. After some testing, I found that the printer’s poop door is spring-loaded, and sometimes it would stay open. That caused the printer to purge filament down the chute, creating long strings that eventually clogged it.
To fix this, I applied a bit of Teflon tape to the lip of the chute and the door. I also placed a small piece of foam behind the door trigger (or whatever you want to call it). I haven’t had a single clog since.
Yeah, the internal ptfe tubes are often cut too short, I don’t know how and why it happens but they really should give them at least 1 extra centimeter of tube length.
Me personally, I like the really clear tubing so I can see what’s inside and if there are any breaks. I replaced the stock smoked gray one with clear tubing but kept the same length.
My take on this is that it comes from all the complaints about the PTFE tube touching the top glass. Making it 1 cm shorter will prevent it from touching the glass, but it introduces other problems in the system.
That’s why, in earlier threads, I have tried to ask why Bambu Lab users want a particular change before checking whether that change would create other issues.
I don’t have room on the left side with all the AMS units I have. However, I did test it on the left side while troubleshooting and still got the AMS motor error. I even tried placing it on top of the printer, and the issue still occurred.
Thanks for the link, I’m tempted to order some, they seem very insistent that it is PTFE. But reading the reviews I’m leaning more toward it being FEP.
The ad copy reads like typical Chinese product advertising, “imagine this actually were PTFE, what would the properties be” type copy. Have you ever noticed that all Chinese filament is somehow all excellent tolerance, no tangle, 360 degree bend radius, and guaranteed no clog? I suspect that is what that tubing is also, there is no incentive not to lie, so why not lie?
I I really like these compared to the frosted ones. I have them on all my printers and AMS units and haven’t had any issues so far. I mean, it is Amazon and you get a lot of Chinese sellers on there, so there’s always a chance they’re lying lol.
That’s up to you. I think the tape is more forgiving when it comes to wrinkles and seems to apply cleaner. But both options work and help keep the waste from sticking. I would also put it on the slide on the printer as well — I found that helped a great deal for me.
My two AMS are set up the same. I am having issues with filament retracting and motor overload issues as well. Not all the time. It’s completely random and seems to happen more with PETG than with PLA.
I have tried with different spools as well. Getting the retraction issue with a single color print is definitely driving me a little batty.
