Extruder 2 doesnt prime

Each duel filament print i do has had issues with the second extruder not printing for the first 5-10 seconds. It does not do a purge line with the second extruder. I dont want it to do it between each change, just the first time each extruder is used as its fine after that.

Im not even sure a purge tower will help much on the initial first lines of extruder 2.

Any help would be great.