"How does one check the hand pump on the injector??? I dont even know where that is (I must be stupid)"
On the W115 300d there is not a hand pump on the the injection pump. To prime the system after changing filters there is a black round knob on the primary fuel filter. (You pump it until you see fuel in the return)

t walgamuth is right about replacing the plugs. I asked a similar question and am now glad I didn't change over. In my case the ground wire was completely melted (when I tried to remove it from the plug it cracked off in my hand!!) Check your ground wire, I replaced mine and my starting has never been better.

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'84 190d 2.2 - Silver
Converted to 5-Speed
'84 190d 2.2 - Blue
Factory 5-Speed

'76 300D (W115)
Sold, found again in less auspicious circumstances