Need some remedial nozzle height assistance

[WatsonGravy]

I'm having a similar issue with the ABL. My Z_PROBE_OFFSET_FROM_EXTRUDER is -0.70 with the paper loose between glass and nozzle. I load a print, it runs g29, starts print and the nozzle is hitting the bed. I change the offset to -0.50, upload and run the print again with the same result. Nozzle is still hitting the bed. I adjust the offset multiple times till I'm finally at 0.0 and still hitting the bed.

Update.. Changed the offset from -0.70 to 0.70. This should get me high enough to "air print". I saved and uploaded. It is still touching the glass. I can bring the Z up manually .20-.30 and it's off the bed. Could I have another setting off in Marlin or could it be Simplify3d?

Eqn coefficients: a: -0.00 b: -0.00 d: -2.24
planeNormal x: 0.00 y: 0.00 z: 1.00

Bed Level Correction Matrix:
0.999995 0.000000 -0.003181
-0.000001 1.000000 -0.000409
0.003181 0.000409 0.999995
echo:endstops hit: Z:-3.01
echo:Active Extruder: 0

[LuckyImperial]

I'm having a similar issue with the ABL. My Z_PROBE_OFFSET_FROM_EXTRUDER is -0.70 with the paper loose between glass and nozzle. I load a print, it runs g29, starts print and the nozzle is hitting the bed. I change the offset to -0.50, upload and run the print again with the same result. Nozzle is still hitting the bed. I adjust the offset multiple times till I'm finally at 0.0 and still hitting the bed.

Update.. Changed the offset from -0.70 to 0.70. This should get me high enough to "air print". I saved and uploaded. It is still touching the glass. I can bring the Z up manually .20-.30 and it's off the bed. Could I have another setting off in Marlin or could it be Simplify3d?

Eqn coefficients: a: -0.00 b: -0.00 d: -2.24
planeNormal x: 0.00 y: 0.00 z: 1.00

Bed Level Correction Matrix:
0.999995 0.000000 -0.003181
-0.000001 1.000000 -0.000409
0.003181 0.000409 0.999995
echo:endstops hit: Z:-3.01
echo:Active Extruder: 0

Try this and report back:

After just turning your printer on do a G28 to home. Send a G1 Z20 F2000 command to place your head at 20mm above the bed. Slowly move the head down .1-1mm at a time until it slightly grabs a piece of paper. What is the Z Height reading? It should be 0.00. If not then your Z-Height is set incorrectly. Note that I never instructed a G29 command. This process was just to check that your build height is correct. If it's not, then you need to adjust your build height until it slightly grabs paper at 0.00.

After you have set the correct build height you can try ABL. Pop your Z Probe down and send G29 Z5. Once it completes the ABL, send a G1 Z20 F1000 and see what happens. Does it look like 20mm? Do you need to raise or lower your G29 Zx number?

Remember that ABL is not necessary on a machine with a decently level bed and good manual calibration. More time should be spent achieving an ACTUALLY level bed then trying to get ABL to compensate. A nice metal ruler and some aluminum foil will help shim that bed to level in no time!