RottiRocket

Hey everyone new here, hope that we can find a solution to my issue! Got an 84 300sd, changed out the glowplugs, but still not firing up unless I have the car plugged in (that little plug which heats the block up). I figured it may be the glow plug relay which could have possible went bad, and swapped in a new relay, but still i'm having cold start issues! Any input would be great, thanks! Oh btw car has 170k on the odo just an fyi =P