Hi there, our 940 2.4TD just failed its MOT on emissions. When the turbo kicks in there is a huge trail of dense black smoke. No power loss though. Have tried changing fuel filter and filling it with injector cleaner, no better. There is a pipe though whcig goes from the exhaust to the inlet manifold. From this point on the inlet is filled with 3-4mm of back oily rubbish. On the middle of the pipe on top of the engine there is a gold valve connected via a yellow pipe to an electronic actuator. should I try to disconnect this. i have also been told to replace the gasket on the induction manifold. Intercooler and pipes are not excessively dirty inside.
help greatly appreciated
Steve