9 times out of 10, when I can't start an engine, it is because I am using a really crappy glow ignitor or the batteries in the glow ignitor are dead. That is the extent of my experience lol. Took me a while to figure this out. I used to take the glow plug out and put it in the ignitor and if it didn't light up all the way to the end of the coil I would throw it away. What a maroon. I wasted a lot of good plugs, I'm sure.
If you are using one of these, throw it away and get a better unit
http://www.google.com/products/catal...d=0CC8Q8gIwBg#