The turbo failed on my 2011 Great Wall V200. I heard a small backfire and saw a small amount of smoke from under the car, and the car lost power. The RAC did a roadside check and said the turbo had failed and was damaged, so I got the car towed home. My mobile
mechanic inspected it and confirmed the turbo was cactus. New replacement one was fitted today, all hoses checked for any leaks or holes, hose clamps replaced, intercooler checked. After completing the work the oil and filter were changed. The car kicked over first try went for test run and no power; it was as if the turbo was not engaging. The turbo was inspected and all was found to be in good condition with no damage visible. Something must have been missed, maybe a relay, sensor or an electrical component that has been overlooked. Any ideas?
You appear to have covered all the bases, so I would suggest you have it checked by another mechanic.