Bedlevelling (all types) is always slightly off. (no replies)

Hi,

Just wondering if I could ask some advice on this :

I am using a BLTouch, I have tried

- UBL
- Linear
- Bilinear
- 3 point
- reverting to 1.1.4

and the results are always variations on a theme :



Right side gap slightly larger than left, as though the levelling isn't doing its thing.

I have tried lots of variations on start gcode, currently it's (for bilinear):

M140 S80 ; set bed temp
M104 S150 ; begin preheating extruder temperature
M190 S80 ; wait for bed temp

;M111 S32 ; logging on;
;M111 S247 ; max detail logging

M502 ; Factory Reset
M500 ; Save Settings
M501 ; Load Settings

G28 ; home all axes

;M420 S1 ; Enable bed levelling (this probably isn't actually needed)

;G29 P1; UBL levelling
G29 ; Bilinear levelling

;G29 T ; View the Z compensation values
;G29 S1 ; Save UBL mesh points to EEPROM slot 1

;M500 ; Save EEPROM

G0 X0 Y0 Z20 F2000; return to front left corner

M140 S[bed0_temperature] T0 ; set bed temp for layer 1
M104 S[extruder0_temperature] T0 ; begin preheating extruder temperature for layer 1

M190 R[bed0_temperature] T0 ; wait for bed temp
M109 R[extruder0_temperature] T0 ; wait for extruder temp

M851 Z-1.85

G1 X0 Y5 Z0.2 F3000 ; get ready to prime
G92 E0 ; reset extrusion distance
G1 X150 E10 F600 ; prime nozzle

(yes it has extraneous M50X in there, I've been trying just ensuring EEPROM is blanked prior)

At this point I think I've tried everything and am at a bit of a loss what to do next.

I came up with the idea of using Repetier to test if alternate software could manage it, just to try to rule out if it's Marlin or something else that's the issue, but Repetier and BLTouch do not seem to get on too well. :(

I'm thinking maybe I could start hacking the code to have Marlin output some debug status messages while it is printing, but C is not really my thing and it's difficult to know where to start.

Does anyone have any ideas?

Is there a way I can troubleshoot this to try to pinpoint the issue? Is there a way I can have the firmware confirm it is indeed using bed levelling?

Any other ideas?

Cheers!