Update. Firstly stipped and cleaned the injectors, inlet manifold, inlet ports. Then cleaned out all the carbon build-up from injector-2 port in the head (
other three were fairly clean but did them as well).
Cleaned out the vortex crank breather, but wondering if this would be better replaced with the original foam filter type ?
Removed most of the carbon build-up from the EGR. It does not seem to open with vacuum on the diaphragm, so might consider this an "EGR bypass" !
Re-installed the injectors, breather & connected leak-off test. Turned it over for 20-30 seconds & then it started up. Smoke everywhere, so put manifold back on & sealed the EGR !! Leak-off now fairly balanced (
but not perfect) between all four injectors, so that's progress.
Finished re-assembly & ran the engine to warm up. Loads of black & grey smoke from the exhaust. Seems to only reach 65-70 DegC, so thermostat needs sorting. Cleared a couple of faults from running it with inlet sensors disconnected. No further fault codes.
Took the car for an Italian Tune-Up. After a few miles the smoke reduced & now only small puffs when accelerating hard. It does feel much quicker on acceleration, although I have only driven it once before the work.
Remaining issue - Even after warming to 70deg the idle is quite lumpy, but smooths out as the engine is revved above 1000rpm.
Attached are a PDF & Excel files with the sensor readings during the Italian tune-up. These were recorded using my iCarsoft CR-MAX. Feel free to have a look & see if there's anything obvious that might still be wrong.