Mitsubishi L200 thick grey smoke

White smoke occurs when raw diesel comes through the exhaust completely intact and unburned. Some causes of this include…
Faulty or damaged injectors

Incorrect injection timing (could be a worn timing gear or damaged crankshaft keyway).

Low cylinder compression (eg caused by leaking or broken valves, piston ring sticking, cylinder and/or ring wear, or cylinder glaze)

When white smoke occurs at cold start, and then disappears as the engine warms up, the most common causes are fouling deposits around piston rings and/or cylinder glazing. Use of our Flushing Oil Concentrate and FTC Decarbonizer address these respective problems.

Water entering combustion spaces will also create white smoke. Faulty head gaskets and cracked cylinder heads or blocks are a common cause of water entry, and are often to blame. Unfortunately, expensive mechanical repair is the only proper solution here.

Are your glow plug,s working okay,and is your filter req,replaced,any codes logged to help you? Is the correct air getting into the engine ,not jammed egr or throttle.

had this problem with a friends replaced the glow plugs and that helped regarding the poor starting but would suggest you use ngk glow plugs or denso ones but there is a starting point for you easy to replace too not a big job