Same GCODE causes different start commands

I've noticed, that printing the exact same GCODE sometimes produces different "Start GCODE".
My Start GCODE is the "default", which i got from CURA. It heats up, homes and then draws two lines on the left.
Sometimes printing this GCODE causes the followin behavior:
It heats up, homes and then lifts the nozzle about 5mm and extrudes along the left side "in the air". Getting to the rear left position it extrudes a "haufen" (german for 'bunch','heap','parcel'). Then the nozzle goes down to the bed and the print starts.
When i cancel this print (because the extruded filament does not stick to bed and hangs on the nozzle) and start again with the same GCODE it usually draws the two lines.

As i don't know if this may be a desired behavior, i did not look at the logs or anything else.
Somebody else seen this?

Here is my Start GCODE:
; <Ender 3 custom Start G-code>
;G90 ; use absolute coordinates
;M83 ; extruder relative mode
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M104 S[first_layer_temperature] ; set extruder temp
M109 S[first_layer_temperature] ; wait for extruder temp
G28 ; Home all axes
M117 Purge Extruder
G92 E0 ; Reset Extruder
G1 Z5.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed
G1 X0.1 Y20 Z0.3 F5000.0 ; Move to start position
G1 X0.1 Y200.0 Z0.3 F1500.0 E15 ; Draw the first line
G1 X0.4 Y200.0 Z0.3 F5000.0 ; Move to side a little
G1 X0.4 Y20 Z0.3 F1500.0 E30 ; Draw the second line
G92 E0 ; Reset Extruder
G1 Z5.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed
M117 Lets make it!
; </Ender 3 custom Start G-code>

Latest OctoPi with Ender 3 Pro and Marlin 1.1.9; PrusaSlicer 2.0.0

The first thing that jumps out at me is the G90 and M83 lines are commented out! This start GCODE will behave differently depending on what the last state was. Remove the ; from the beginning of those two lines and I believe you will get more consistent results.

2 Likes

Thanks in advance. Will try that later today.