Injection Molders-

I've been struggling with an adhesion issue between my 1st and 2nd shot overmolds. Previous attempts to mold have been successful but after recent maintenance to the machine, I cannot seem to find a process to eliminates an adhesion issue between overmolds. Material is Pebax. Running barrel temps around 430 and nozzle around 460. I've been mainly adjusting just the nozzle temperature from 430 to 460. I get better adhesion with hotter temperatures but still have a parting line. I've increased injection pressure to try to push the material in faster and have opened up the mold vents to make sure that I am not trapping air. The increased injection speed seems to have reduced voids. Backpressure and hold pressure do not seem to have a impact. Thoughts?