Every one has made valid suggestions.
If the valves have not been adjusted, do it. You wont believe what a difference it makes to cold starting & running.
Take the GP's out & bench test. You need to see them glow nicely.
Parking the car nose down on a hill with a full tank overcomes any air leak into the fuel. If you you try that & it starts good then you have an air leak into the fuel.

Good luck !!

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving