Hard starting - quick question on my '78 300D

[rgnprof]

I have - hopefully - a quick hard starting question. During the summer, I attempted to adjust my injection pump timing (some my remember those threads) - anyway, my question is could/would that effect my starting this car in cold weather? I am having a MUCH more difficult time getting it started if it gets cold here and when it does start there is quite a bit of black/blue smoke. I realize there could be numerous issues here - but I have replaced the injector nozzles and glow plugs - and if it's warm enough (40's, give or take), then it starts. Just curious about the timing issue.

BTW, I advanced the timing (rotated the pump toward the motor) in the summer.

ryan