Nozzle Crashing into Bed - Ender 3 S1 Pro

Have printed a lot of items with bad to marginally OK results. Decided to adjust all axis’s and done. Printed Temp, Retract towers + Cali Cube, Cali Cat. Somewhat better than before. Went to print Benchy an upon 1st contact point with nozzle the z-motion did not stop and proceeded to hit the bed, depress the bed to max then motors trying to go further down. Had to turn off the printer.

Guessing the CL Touch was bad. However, at about apx 50mm the CL Touch will stop the down Z movement.

Checked the Z offset still at -0.85. On Touch Screen I stopped the down Z and changed the Z Offset to 0.00 and still the crashing. I haven’t set Z Offset to a + number to test.

At this point the printer is unusable and looking for help/ideas.

Maybe the z-limit switch is bad or the wire is loose.

Is it possible to run the printer with the CL Touch disconnected to eliminate a variable?


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Moving the z-offset to 0 you actually moved the nozzle closer to the bed. On my Pro my z-0ffset is -1.45 but may be different for you. After I set my z-offset manually I then print a 60x60mm 1 layer square that I use to fine tune it live. I will adjust the z-offset a tiny bit like 0.05mm at that a time. Till I get a good 1st layer. Sometimes it takes several of the squares to get it correct.

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Previously have printed a lot of items - less than desired quality but sort of use able. I had just gone through adjusting all rollers on all axis’s. Static bed Tram and went into leveling steps on the 3 S1 Pro.

Previously my working Z adjust was -0.8 - working but various print problems, layer shifting and some small layer gaping. Some prints would fail midpoint.

After the adjustments and completion of the onboard leveling, Z offset -0.8 I printed the items mentioned above. Temp, Retract towers, cali-cube, cali-cat. Next print was to be Benchy. Started that print and on the initial home probe is when the nozzle crash happened. I set the Z offset to +2.0 and still crash. More info in a additional reply.

I apologize in advance for the long read.

With further problem solving, I had learned the CL Touch would work at about 3 inches above the bed. Since I have been testing the height at which the CL Touch would fail. At Z offset 0.00 (now) fail begins at about 1-2 mm above current bed height. I will get an exact height later on today.

I was trying to eliminate layer shifting as well as tiny layer separation marks. I am printing and wanting to sell items that are from 15mm sq, or oval to 60mm sq or oval. 14mm tall. 3 wall will widths, 1 layer 2 to 2.4mm thick 3mm tall. Second layer 1.2mm thick and 3rd layer 0.41mm tick and 5mm tall (lowered 1mm into layer 2). Resulting in a step taper to a total height of 14mm. I am getting random tiny layer separation marks throughout the layers. The marks are generally grouped in the same general area and on different layers. I can reprint the same item and the mark may show up in different spots.

I didn’t have this problem on my 3 v2 (now sold). But the issue is showing up on two 3 S1 Pro’s.

I removed the bed and adjusted the Y axis wheels - no movement. Power off and Trammed the bed. Springs compressed about 60% there is still some slight bed movement. Tightened the springs to about 75%. I did get 4 successful prints but crashed on the 4th (Benchy). Repeated both cali-cat & cali-cube both crashed. I don’t know how to insert a picture as that would save a lot of reading for folks.

I could loosen the springs more raising the bed level but then I am introducing bed wobble back into the mix.

I see people using solid spacers rather than springs. To me that seems to introduce a big risk of equipment damage.

Any thoughts or ideas would be appreciated. For now: 1. I am going to attempt to locate if the CL-Touch is failing at a given level - 1 to 5mm above current bed level using using a false bed consisting of spacer(s) and a glass bed I have on hand; 3. Hope I don’t have to do this but replace the print head & CL Touch on my #2 problem printer from the #1 working S1 Pro print.

FYI. Print quality on both 3 S1 Pro’s are poor and the results are not sell-able. Results from my old 3 v2 did not have layer wobble or tiny layer separation.

Just a thought… CR touch is a fairly simple device, and it shouldn’t be sensitive to height above the bed surface. I wonder, though, is it possible the wires connecting the CR touch to the processor in the base are flexing enough to cause an intermittent connection problem? Perhaps the connector is not pushed in securely?

As one experiment, you might try running a different 5-wire cable from the system to the CR touch (i.e. bypass the cable that’s in the bundle) to see if the behavior stays the same.


I have seated all plugs topside and was thinking taking off the base cover and checking the MB plugs, great thought and the next step. I was thinking of taking off the print head of my 1st 3 S1 Pro and Testing each on the other machine… really not wanting to do that at this time. I didn’t think of getting a 5 wire connection and trying that - good idea, I need to order one.

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After trying a lot of things - putting on different wiring; checking all plugs. I got tired of the problem and returned the 3 s1 pro and got another same printer.

I am thinking I should have bought the 5 Pro.

On both my Pro’s 0 offset well put the nozzle a few mm above bed after I do a power off leveling. Then I have to lower the offset to -0.185 get achieve a proper height.

I also do a live leveling with the 60x60, 1 layer. I activate the auto leveling in the gcode. I am wondering if the Ender auto feature eliminates the ‘live leveling’ once a new print is started?

I don’t think there is a physical lower Z limit switch.

It sounds like there are several different things going on. Focusing on the CL Touch, have you tried disconnecting it? There is a z-limit switch according to this article, fwiw.