hi kcboy,

from your post. i don't think your plugs need to be replaced. you might want to check improve your electricals for your glow plugs. especially the relay and timer relay. kung mahina ang takbo ng koryente sa glow plugs mabagal uminit sya. i had the same problem sa pajero ny company namin. if one or two glow plugs are not working you'll notice parang pumapalya and andar niya when you start. the black smoke is normal if your hardstating cuz your cylinders are full of deisel from all the cranking. once you solve that problem the black smoke will go away.

BTW. if you wand to check the glow plugs. simply unscrew them. dip the tip of the plug in light oil. attatche a wire at the top of the plug. them stick the body of the plug to the negative pole of your car battery and the wire on the positive. in less that 10 sec the oil will evaporate (smoke). that means ok ang glow plug mo. be carefull not to touch the tip after cuz mainit-na mainit yun.

mintoy