you should be seeing NO, that is -zero- debris, and no color change in the fuel flowing INTO the injpump. #1 thing, change out fuel filter and keep it and air filter in proper order.
debris, or coloring running into injpump can quickly foul it. and on to injectors.
i prime a new fuel filter(use inlet).
another thing when it gets cold out, ooh for me about,below 20dg f and lower, a good amount of anti-gel, like the power service stuff, then again ive heard in some cases that stuff isnt always warranty covered/acceptable. i also use some fuel treatment along with.