Started car today and have clouds of blue smoke on idle and very rough idle (my97 sti). I have just removed the intercooler and found oil inside (assume turbo fubared). Started it up without the intercooler on and blue smoke turns to black /grey smoke so would it run mega rich and rough on idle without intercooler?

 

Check the oil and make sure it wasnt over filled.
Clean all the pipes and re-fit.

Do a compression test and make sure it's not the rings that are passing oil

If all is ok and the fault raises it's head again, chances are that the turbo is goosed.

It shouldnt run well or at all unless you put the MAF where the i/c was as it doesnt know how much air there is

 

You can’t run the car with the intercooler disconnected even for seconds your allowing air to bypass the maf so yes it will run incredibly bad.

It’s common to find oiling inside the pipe work due to the pcv system feeding the vapors back into the inlet.

If you are continuously having blue smoke on start up, it could be due to the turbo oil seals leaking, but I would also expect smoke on de acceleration. Another thing could be the valve seals.

Let the motor run and see if it clears, and if it is only start up situations it smokes I would suspect one of the above.

 

Smoke doesn't clear even when warm but with intercooler disconnected there is a mist of of oil from the turbo outlet
I bought the car with the problem and there is a bill for a vf34 of £700 3000 miles ago also has a prova ecu. If i were to return it to stock what turbo and ecu should i be looking for?
Thanks for the help guys

 

Yep Sounds like the oil seals have gone.

Depending on the condition mileage of the unit etc it might be more cost effective to look into having the unit rebuilt rather than splashing out on a new turbo. I think your original turbo unit was a vf22 or Td05 would need to confirm this.

Your oe ecu number 6K

 

got a vf22 here, pm me if you want it