Having a strange problem with the left extruder of my flashforge creator pro I have now for 2 years. When the left extruder does a retract / travel and does ooze control, it seems like the retraction distance is very high regardless of what I set in software. Like 4mm or more. When there is only a retract once every while the result is little gaps appear just after the retract/travel. The restart distance does seem to have the normal value though, like 1 mm. So for every 4mm retraction the filament gets pushed only 1mm back in.
When things get real nasty is when there are a few retracts quickly after each other. After 4 travel moves, the filament gets retracted 4x4 = 16mm! But is only pushed back in 4x1=4mm. Result: the filament even gets pushed upwards out of the extruder by 12mm and the model fails.
The right extruder is perfectly fine! And all other functions of the printer also work. I can load and unload filament in the left extruder and the extrusion itself is fine too. Temperature is also good. The retracting on the left extruder is just very strange.
Anyway, I can compensate the big retraction by adding a big extra restart distance of 4mm for example. But now the filament gets jerked up 4mm and down 4mm, making the extruder gear grind on the filament with unpleasent noises.... Also this aint a real solution and the model doesnt look as nice as it should.
I tried different slicers with different settings. But whatever I do, the left extruder has the weird retraction error and the right extruder is perfectly fine.
Also tried the following hardware things:
-Swapped stepper motors from left to right extruder--> No difference
-Checked cables with multimeter from extruder to mainboard --> All ok
-Swapped the removable Stepper Drivers (litte PCB's) around that are on the mainboard --> No difference
-Checked both extruders for jams and other errors --> All clean and good.
-Tried different filament --> Same result
-Put on new original nozzles --> No difference
-Leveled the nozzles and the heatbed to almost perfect settings --> No difference
-Updated firmware with FlashPrint to: ff_creatorx-2560_v7.8.0-Pro-20160523 --> Didnt solve the problem.
-Delete / reset EEPROM --> No difference
-Printing directly from computer instead of SD --> Same result
Also did some software things:
-Turn of retraction all together --> Left extruder prints ok, but with stringing.
-Set a very low retraction distance of 0.1mm --> Filament still gets pushed up by large amounts
-Set a very high extra restart distance of 4mm --> This kind of helps, but with grinding extruder gear and not so good print.
Anyway... I'm kinda out of ideas why this is happening except is a mainboard problem. And thats not cheap and altough it's still cheaper compared to a new printer, I do wanna make sure it fixes this problem. Any idea's what's going on here?