Issue with Resuming Print via Custom G-code – AMS Filament Not Feeding

[Wild_Tigra]

Hi! I ran into such a situation:

Printer: Bambu Lab P1S Combo
Material: PLA (in AMS, slot 1)

Manually stopped and canceled the print.
I want to resume printing from layer 15, because layer 14 was definitely completed successfully.

In Bambu Studio I trimmed the model from the bottom to layer 15 (Z=3 mm),
but when I start the print, the new part starts printing directly on the bed as if the model starts from scratch.
I decided to continue the print using custom G-code manually.

I set:
G92 Z3 (my layer 15 starts at Z=3 mm)
Positioning and movement work correctly — the head moves to the right place.
But! Filament is not extruding — the nozzle just moves around, but there’s no print.

T0
M701 T0
or
T0
M621 S0
tried both — doesn’t help.

What are the correct commands to:
Load filament from AMS (specifically spool 1 / slot 0)
And reliably start extrusion from the nozzle?

Do I need to add any commands like G92 E0, M83, G1 E…, to force it to start extruding?
The beginning of the code is attached below.

Thanks in advance for your help!

; ===== Safe homing before filament loading =====
M104 S140                 ; set safe nozzle temperature for homing
M109 S140                 ; wait until nozzle reaches 140°C
G28 X Y                   ; home X and Y axes
G90                       ; absolute positioning
G1 X10 Y10 F3000          ; move to safe position
G28 Z                     ; home Z axis (safe at 140°C)

; ===== Motion configuration =====
M201 X20000 Y20000 Z500 E5000
M203 X500 Y500 Z20 E30
M204 P20000 R5000 T20000
M205 X9.00 Y9.00 Z3.00 E2.50

G1 Z3 F3000
G92 Z3                    ; tell firmware that Z=3 (start layer height)

; ===== Filament loading and heating =====
T0                        ; select tool
M620 S0A                  ; select AMS if available
M621 S0A                  ; load filament from AMS slot 0

G1 Z50 F3000              ; lift to avoid collisions before cleaning
G1 X60 Y265 F5000         ; move to purge zone

M104 S250                 ; heat nozzle to 250°C
M109 S250                 ; wait until target temperature reached

G92 E0                    ; reset extruder position
M83                       ; enable relative extrusion mode
G1 E50 F200               ; purge 50mm of filament

; ===== Nozzle shaking cleanup =====
G1 X60 F15000
G1 X80 F15000
G1 X60 F15000
G1 X80 F15000
G1 X60 F15000
M400                      ; wait for all moves to finish

M104 S220                 ; set working temperature
M109 S220                 ; wait for 220°C to stabilize

G92 E0
G1 E5 F300                ; prime the nozzle
G1 E-0.5 F300             ; slight retraction before travel

; ===== Prime lines on Z = 0.2 mm =====
G1 X20 Y5 F3000
G1 Z0.2 F3000
G1 E5 F300
G1 X200 Y5 E12 F1000
G1 X200 Y6 F500
G1 X20 Y6 E12 F1000
G4 S2

; ===== Move to actual print position =====
G1 Z10 F3000
G1 E-.8 F1800
G1 X204.987 Y91.95 F30000
G1 Z3
G1 E.8 F1800
M400

[Ruby_in_Wyoming]

@Wild_Tigra

Manually stopped and canceled the print.
I want to resume printing from layer 15, because layer 14 was definitely completed successfully.

In Bambu Studio I trimmed the model from the bottom to layer 15 (Z=3 mm),
but when I start the print, the new part starts printing directly on the bed as if the model starts from scratch.

Normally, when you do this, you take the partially printed print off of the bed and start printing from the bed, then when completed you either glue or weld the two pieces together. I don’t know of any way to make it start printing on the top of a model left on the bed.

[Wild_Tigra]

Switching to this version of the code (found on the forum) BBL P1S organized start and end gcoderesolved the issue with filament not extruding properly after restart. Thanks to everyone who helped!

; ===== Filament loading and heating (based on AMS logic) =====
M620 M                    ; Refresh AMS status
M620 S0A                  ; Select AMS slot 0 for tool T0
M109 S220                 ; Set and wait for initial layer nozzle temperature

G1 X120 F12000            ; Move to start of the purge path
G1 X20 Y50 F12000         ; Enter purge zone
G1 Y-3                    ; Drop filament blob outside the bed
T0                        ; Select tool 0
G1 X54 F12000             ; Move to start of wipe line
G1 Y265                   ; Move along wipe line
M400                      ; Wait for all movements to finish
M621 S0A                  ; Load filament from AMS slot 0

; Filament flushing at calculated speed and temperature
M620.1 E F299 T240        ; Purge with specified flow rate and temperature

; ===== Physical nozzle cleaning and shake to drop residue =====
G1 Z50 F3000              ; Lift head for safe purge
G1 X60 Y265 F5000         ; Move to purge zone
G92 E0                    ; Reset extruder position
M83                       ; Enable relative extrusion
G1 E50 F200               ; Purge 50mm of filament

; Shake the nozzle to remove residue
G1 X60 F15000
G1 X80 F15000
G1 X60 F15000
G1 X80 F15000
G1 X60 F15000
M400                      ; Wait for movements to finish

; ===== Transition to working temperature =====
M104 S220                 ; Set working temperature
M109 S220                 ; Wait until temperature stabilizes
G92 E0
G1 E5 F300                ; Prime the nozzle
G1 E-0.5 F300             ; Slight retraction before printing

In the photo, the red part is the resumed print, and the white part is the first 14 layers after which the print was interrupted. I’ve had the printer for 5 days, and this feels like a small victory for me in solving the issue. Thanks to everyone!