BLTouch won't lower the Z-axis when auto-homing
I've seen this issue come up a lot in forums with the BLTouch, and I have tried every solution that was given that I could find. I have an ender 3 V2 and just installed a BLtouch. It worked perfectly for the first 3 days, but one day I took off the old print, went to start another and the the autohoming didn't work. well the x and y axis worked perfectly, but the z axis wont lower. I have seen a lot of solutions to this so Im just gonna bring you up to speed on what I've tried.
1. turnrf it off and on
2. made sure the bltouch was plugged in
3. made sure the wires weren't crossed, although I didn't think this would be the issue since it did work earlier
4. checked the connection in the wire
5. checked for shorts in the wire
6. checked for connection between the bltouch, the wire, and the motherboard
7. unplugged bltouch, reinstalled original firmware, plugged z-stop back in. it works fine like this but I want to get the bltouch working.
8. downloaded new firmware and installed it, then plugged bltouch back in.
after all this it still doesn't work
I am having the exact same issue, worked fine (Was running jyers firmware) suddenly stopped working. I saw a few bits of info around the web about sheilding on the BLTouch cable so I even went down that road. Just prior to sheilding the cable I had flashed the mriscoc fork from here ( https://github.com/mriscoc/Marlin_Ender3v2/releases) as an attempt to fix the issue. It didn't fix the issue (Although I really liked the look of the firmware) but after seeing the sheilding issue I did a test by isolating the BLTouch cable from the other cables to the hotend by simply removing the cable ties I had used to hold them together and holding the BLTouch cable out as far as practical from the machine, then I tried a bed level with the mriscoc fork & it worked perfectly. I thought I had found the issue (Sheilding) so I spent hours pulling cable, wrapping sheilding around the BLTouch cable & earthing it etc. Switched the machine on and the BLTouch was not working again! Basically back to square one.
After flashing and re-flashing various firmware in an attempt to fix it I have found that regardless of which firmware I run it seems that I cannot get the printer to find z home or zero. What the printer thinks is zero on Z axis is actually about 13-20mm off the bed. I have re-configured the printer so many times with so many different iterations of firmware etc and nothing works. I am now going back to the original pre-BLTouch firmware from Creality download page, resetting the machine and leveling the bed. I will do a test print & then attempt to re-install the Jyers firmware with BLTouch. I read somewhere (I've read so much about this issue I can't remember exactly where I saw it) that there may be an issue with installing firmware with the BLTouch already installed physically. I believe the theory is that you are meant to go back to basic settings pre-BLTouch, install new firmware, THEN install the BLTouch. I don't think this will address the issue that caused the sudden failure however if it gets the printer to find zero on the Z axis atleast I'm halfway there.
Not sure if it's going to work but at this stage I am out of options & about to throw the BLTouch & the printer on the driveway, get in my car & run it over...and over...and over! I'll let you know which way I went soon.
As a side note, The reason I'm going to this much trouble and not just removing the BLTouch is that my bed is so warped that printing anything outside a 25mm X 25mm square from the centre of the bed is impossible without auto levelling. The BLTouch, when it was working, solved this issue brilliantly and I had a week or more of trouble free easy printing before the sudden fail.
UPDATE - I didn't want to puncture a tyre on my car so I decided not to run the printer over. I did however remove forever the BLTouch. It seems to be the root of all my issues so I have reinstalled the JYERS firmware & gone with the manual mesh option which is now working very well for me. Given that my bed is warped and the mesh looks like a snapshot of the Appalachian Mountains I would love to see a mesh that has more test points across the bed however it is working & atleast I can now print again. I might revisit auto levelling down the track and perhaps go with something other than the BLTouch, it was great when it was working & saved some time.
On a side note, after having these issues & reinstalling the HYERS firmware I seem to have a gremlin in the system that has affected the Z Axis. Now on every print the Z axis shows some very wierd readings, like 500, then 25, then 144 etc, its all over the place. This doesn;t seem to affect the printing & homing all does zero every axis. But as soon as I start a print it loses the Z axis on the readout during printing. Like I said it doesn;t seem to affect the print so I guess I can live with this little quirk.
Have you found any solutions to this, I've noticed the core of the issue is the probe not fully deploying in my case, just drops by a few mm... and goes back up...