Glow plugs: what's this mean?

[elrojo63]

Truck became really hard to start yesterday. Temps in high teens low twenties and it didn't want to start. Eventually did with a bunch of cranking and white smoke. This came on suddenly. Two days ago it started in these temps with no issues.

I checked glow plug resistance and all of them wouldn't give a reading except one gave .9 ohms and the other 28 ohms. Any ideas what's causing this situation? Relay is fine and replaced gp set last year.

[ridiculously_necessary]

check all teh glows again. .9 iirc is ok. 28 i think is high even for a bad one. i would double check the relay was well. the stockers arent always known for their durability.