Key turn buzz

[ParkCity.PSD]

When I turn the key on to let the glow plugs warm up I get a buzzing under the hood. It's louder when the glow plug light is on then trails off. I usually wait until my insight comes up to crank it and the buzzing is done about that time. It's done this since I got the truck and I'm not sure exactly what it is...glow plugs? Injectors?

Anyway, it has always done this every time I turned the key. Over the last couple days, it hasn't done it when the engine is warm. Is this normal or something I should be worried about?

[OUMX117]

There are two noises that you should be hearing. One is your injectors clicking. Mine do it for (guessing) 5 seconds or maybe a bit longer if the truck is cold. The other noise that sounds more like a pump is the vacuum pump. Both of which are perfectly normal.

[Lilpooh]

It's the injectors. Warming up the spool valves, or cycling them.
http://www.backglass.org/duncan/2003...ih_reflash.pdf

[ParkCity.PSD]

So, why isn't it doing it every time I turn the key now? It used to do it all the time

[Lilpooh]

Originally Posted by ParkCity.PSD

So, why isn't it doing it every time I turn the key now? It used to do it all the time

That I don't know. I don't know enough about what's involved with pre-cycling or Inductive Heating.