I am having a starting problem with my 93 GMC 6.5 diesel when it is warm outside, or the engine is warm. It starts fine when it is cold outside or the engine is cool. Could you please help with any suggestions.

Welcome to the forum..........

Look on the top rear of the Inj Pump for the Stanadyne label - what color is it, and do you see a green tag on one of the top cover screws?

I do not see any place that says stanadyne. No green tags. I was told it was a roosh master pump.

Back vertical face of the rectangular tower part of the inj pump housing - faces the intake manifold.

The black label pumps have hot-start problems due to excess internal clearances - the green tag would mean that it had been corrected with a rebuild.

Other than that, weak batteries, bad cables, poor connections, worn starter bearings, bad solenoid, etc - many areas you may need to check out.

That old '93 hoss is mighty long in the tooth, and could probably stand some 'rode easy, put up dry' care at this stage.

But, first check the Stanadyne Roosa Master injection pump for the black label - if it is the problem, correcting the other stuff might not help, much.

If it's blue, you may be ahead of the game.

What's the mileage on the truck?

the milage is 223.000 original

If that is the original Inj Pump and injectors, you're looking at some way passed due replacement.

Other than that, difficult warm-start is usually caused by low cranking rpm, which can be traced to low batteries, bad cables\connections, and worn starter bushings\brushes.

I suggest having your Inj Pump and injectors tested, and replacing the timing chainset will need to be part of the fix.