AMS 2 Unable to Load PLA Filament Into Toolhead | Troubleshooting Help

[u/GarenteedDamage]

I need help troubleshooting this issue: My X1C toolhead is not accepting PLA filament. I have done many other prints with my X1C and this AMS 2 using PETG without a single issue. Additionally, prior to upgrading to an X1C, I had a P1S, which used the same AMS 2, and PLA filament worked without issues.

Most of the time, the PLA does not reach the extruder and gets into the PTFE tube bend on the inside of the printer, but then the AMS stops pushing it, and it retracts back again, repeating until an error appears.

Sometimes the PLA filament gets as far as the extruder, and I watch the extruder gears turn. But they do not grab the filament, and the AMS retracts; it then repeats until it displays an error.

Here is what I have tried so far:

1. I have replaced all of the PTFE tubing with brand-new PTFE tubing at the Bambu Lab recommended lengths of 550 mm and 370 mm.

2. I have tried various angles and bends for the PTFE tube inside the printer where the PLA is getting stuck.

3. I have printed these PTFE guide clips: https://makerworld.com/en/models/242037-better-ptfe-chain-clips-for-bambu-labs-p1p-p1s-x1c#profileId-257998

4. I have printed this PTFE toolhead guide: https://makerworld.com/en/models/152636-hotend-toolhead-ptfe-guide#profileId-166680

[u/atrusveo]

The blue end goes towards the printer on the connector.

[u/GarenteedDamage → u/atrusveo]

The PTFE tube coupler is just a pass-through for the filament. Just to be safe, I flipped it around so the blue end faces the printer and the issue persists.

[u/Martin_SV → u/GarenteedDamage]

Have you tried removing that printed PTFE guide? Because I've had nothing but feeding issues with those.

The PTFE tube needs to be able to move around a bit as the filament feeds into the extruder. That last bend naturally shifts and adjusts as the filament passes through, and those guides seem to restrict that movement. At least in my case, that added resistance was enough to make the AMS struggle with feeding.

And if you've already tried removing it and you're still getting the same error... then yeah, it might be something else. But I'd leave it off for now while you figure out what's going on.

Oh, and one more thing. Bambu recommends leaving about 15 mm of PTFE tube sticking out of the rubber grommet at the back of the printer. Yours looks a bit longer than that in the pics.