replaced turbo and still same problem


my fourtrak would startup fine, then it would idle roughly and it would smoke like a pig, then the revs would shoot up of the scale, and would eventualy stop about 3-5 seconds after i had turned the ign key off,i posted on this forum, and all the reply's stated that the turbo was u/s and it was allowing oil from the turbo to feed into the intake, having removed the turbo it was infact nackered, there was a good quarter of an inch play in the turbo shaft.
i have fitted a replacement turbo, but the same thing is happening, the engine will start up with no smoke and idle corectly, then again the revs drop and it runs lumpy as hell then it starts to smoke, the revs will then go up to approx 1000 then up to 2000 then off the scale sometimes it will then come back down and idle corectly then it all repets its self, i have even removed the top of the turbo boost compensator and cleaned the diaphram and housuing as it was full ofengine oil from the old turbo. if it dosent apear to be comming down,i then switch off the ign switch, but there is a slight delay 3-5 seconds before it decides to stop.(maybe the delay is lazy fuel cut of valve, not sure)
would a new injector pump cure this problem, has anybody got any ideas, it dosent always smoke when it is in rev bollocks off mode, i thought that it may be dragging up its own oil from sump and burning on this, but if that was the case i would not be able to switch it off and it would just keep on reving until it blew up.........can sombody help me on this matter