Outer Limits 4x4 Board

My mate has Troopy with aftermarket turbo done by MTQ a few years back. It has started cutting out at 3400rpm under load. It blows a plume of white smoke then dies. The turbo has started whistling.Not the normal whistling.
It has had the fuel pump reco'ed,The turbo reconditioned(MItsubishi turbo.) It has had the injectors done. None of this fixed it.
After the fuel pump was done it was ok for a few weeks. Now the problem is back.

Any ideas? The mechanics are scratching their heads.

Here is an extract copy and pasted from the link at the end of the post, its a handy link to save for reference.

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.

http://www.dieselsmoke.com.au/


Added- Another thing, when they did your pump did they do it to factory specs. When I had mine overhauled I had it done to factory specs plus 8% to allow for the turbo and it ran like a charm. Also did they do your timing with a dial guage, that can make a difference too.