on my 83 300D-T

Its 10F outside car is cold soaked
I cycle glow plugs 3-5 times
engine fires right up runs for 5 seconds then quits. After that it wont even pretend to fire and have to wait till later in the day when its warmer to start her up

__________________
Nothing in this world can take the place of persistence. Talent will not; nothing is more common than unsuccessful people with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan "press on" has solved and always will solve the problems of the human race.
Calvin Coolidge (1872 - 1933)

Sounds like some gelled fuel and or plugged fuel filter; particularly the pre filter. Ive had nearly the exact same thing with the same engine as you. I just didnt have to wait as long, but it was warm outside. Mine turned out to be filter problems.

Here is a test to help evaluate the car or to just move it out of the way if this happens in a bad spot (dont ask me why I know). Clamp off 1/2 or more of the return line with vise grips. Now see if it will run. Worked for me. A friendly mechanic saved my arse with that hint.

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"If anyone knows other lessons I need to learn, please tell me. I'm tired of learning them the hard way".
by JerryBro

The Glow Plug Wait: This waiting period is a moment of silence to pay honor to Rudolph Diesel. The longer you own your diesel the more honor you will give him". by SD Blue

My normal daily life; either SNAFUed- Situation Normal... All Fouled Up, or FUBARed- Fouled Up Beyond All Repair

62 UNIMOG Camper w/617 Turbo, 85 300SD daily driver- both powered by blended UCO fuels

Thats a neat trick to know. I tried it did'nt seem to make any difference though. I've just very recently (2000 miles ago) changed the fuel filters. The pre filter looks very clean (as new). No appearance of gelling noted. I'm using one of the diesel power service anti gelling additive.

Its kind of a bizare problem(only when outside temps are 20F and below). As it stars right away on the initial try and runs smooth for 5 seconds then just dies. Once the outside temps come up there is no more problemo, car starts fine, runs with power and the proper gusto of a turbo.

__________________
Nothing in this world can take the place of persistence. Talent will not; nothing is more common than unsuccessful people with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan "press on" has solved and always will solve the problems of the human race.
Calvin Coolidge (1872 - 1933)