r/Bambu

I could really use some help as I have never experienced this issue before. P1S, about two years old, 2500hrs, been a spectacular machine with very little issues. 2 ams units with sunlu heaters attached. Numerous upgrades including biqu tool cover, all metal gears, .4 hardened steel, chamber heater, and filament guides on each of the AMS feeder motors

About two months ago, I replaced all PTFE tubing with brand new bambu lab tubing. I was starting to get some worn spaces and I figured it was time to do it anyways. I replaced every piece of tubing in the entire set up, including the chamber tube, the tube from the AMS hub, the tubes leading back to the two AMS units, and each of the four smaller tubes on the bottom of the AMS units. Everything is as short as I can make it and it’s been working fine for the last month and a half. I haven’t used the printer in about two weeks, and today I keep getting an error on a very simple PLA print that uses PETG interface supports. “Cannot feed filament”. The filament exits the AMS unit, goes through the tubing set up, and gets about 2 inches from the tool head entrance before it stops, retracts, tries again, then produces the error code. It seems to either do this at the start of the print, or it gets about 85% through the print meaning it has had 10 or 15 successful filament changes, and then fails towards the end. I’ve stopped and started this same print about 10 times and I keep having the same result.

What I’ve done:
- I have ran PLA filament manually through every inch of the entire tubing network to push out any old pieces, and I have found none. This includes disconnecting the tubing from the tool head, from the AMS hub, through the two tubing lines going to each of the AMS units, as well as the four underneath sections that lead up through the feeder motors inside the AMS.
- cold pull with no abnormalities
- printer is getting to the correct temp for each filament
- spools are spinning properly and are not getting kinked
- I have tried different spool slots, as well as switching the AMS that holds the actual filament and I have produced the same error code.
- I have removed the tubing from the tool head and trimmed off a few millimeters and all tubing and filament cuts are performed with a proper tubing cutter so that they are straight.
- once again, this set up worked when I first installed the tubing so I really don’t think it is a tubing length issue. I have also shortened the tubing as much as possible while still allowing the AMS units to be pulled out of of the stand. The current tubing is also shorter than the initial set up, which worked for the first two years of the printers life.

Is this simply a symptom of the feeder motors needing to be replaced? It’s simply odd that it gets so close to the tool head sporadically before it retracts. In one of the images below, you can see a red circle which indicates when the error happens how close the filament actually gets.

This is driving me insane so I would really appreciate some guidance from the community. Thank you very much for your time and assistance.

Went to use the Bambu Handy app this morning and they quietly added the option to queue prints??
Update: It appears you can only start the next print from the app at this time, there is no option to start the next print on the printer.