Digital BW, The Print

I installed carts of the MIS archival inkset today (after leaving 
them overnight). After a few purges and nozzle cleanings, the black, 
cyan, and magenta are coming out well. The yellow, however, has been 
coming out in various shades of green. Now it is finally moving 
toward a definite yellow, but I've used more than 1/4 of the ink in 
the carts to get this far. I've cleaned the parking pad, but perhaps 
not thoroughly enough. Is this typical when changing to BW to color?
Any suggestions or guidance would be very much appreciated.

Chris Hargens