Try flushing solution through the pump with the syringe. Maybe the pump is clogged.
I just installed a New Ink Pump and I still cannot get ink to flow through the cap tops.
I have now replaced cap tops, all dampers and O rings and each damper is now full of the correct ink but I still cannot pull ink through the tubes under the cap tops even with a tapper syringe.
When I use a syringe to try and pull ink there is almost no resistance which tells me there in a air leak some where in the system.
I also have replaced all the drain lines with brand new lines and the drain bottle is empty.
Could it be the capping station not creating a good seal?
I clamped off the both tubes below the cap tops and both cap tops are once again full of cleaning solution. I will let it soak for a few hours and see if that fixes the problem.
Not sure what else to try since it appears when I do a test print that both heads are firing correctly but with a lot of drop out in the test prints.
Jim