I have a Toyota diesel which starts well now that I have learned its little idiosycrasies...
I turn it over, then wait 5 seconds. If its cold, I'll press the glow plug button during that 5 secs. Then I turn it over again, and it always starts the second time it turns over. 
I don't know why, but it always works that way.
BTW if you press the glow plug button for too long, it's easy to burn out the plugs. I burned out all 4 of mine, made it devilish hard to start in cold weather. You can easily check them by disconnecting them and measuring their resistance with an ohm meter. Should be low, around 2 or 3 ohms. A dead one measures open circuit.
Geof
Perth WA Oz.
82 Trakka

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