You’re supposed to hold the gas down about 2/3 the way... it says that on cold start up on the sun visor on my 89... i never have issues starting it up
6.9 is a good engine. Are you sure the injection pump is working correctly? I think if the pump is on its way out it will cause the 6.9's to smoke a ton too.
I am familiar with old diesels. I've rebuilt a 1986 chevy 6.2 and I currently have a 91 6.2 suburban. Neither of mine smoke anywhere near as bad, they barely smoke on a cold start.
