the turbo wont boost up unless your engine is under load mate so reving it wont make it come on boost, well possibly 2psi max!,

you need to drive it to see where the boost comes in, should be 2900 rpm if its a standard t3 and exhaust housing,

the smoke will be causeed by either

1, fooked stem seals, (VERY fooked)wont smoke alot on boost but will on over run. and massively when you start!

2, piston rings, smokes hard on and of boost if they are proper fooked!

3, turbo rear oil seal, leaking it into the exhaust housing, is worse just as you come on boost then it clears, and on over run is smokey

could be a combination of all three mate, good luck