Hi every one New to this site! I am an X Vauxhall mechanic and have got a 55 plate X Type 2.0L diesel. I have had a problem with it smoking and engine knocking. No loss of power, No EML. Very bad MPG! Took EGR valve off and gave it a good old clean, Checked the Vac unit and that the valve was moving free and not sticking. All good. Re fitted unit but still the same! looked at MAF sensor and checked wiring all ok! Checked Turbo pipes. All ok. Took vac controll valve off that controlls the EGR valve and that was ok. Starting to scratch my head now! Had a look at the Vac pipes that go to the controll valve 3 in total! and found that the vent pipe from the controll unit to the intake pipe just befor the MAF sensor had come off. If you remove the cover for the top of the battery you can see where it fits on. So put the pipe back on went out for a test drive and all sorted. It was that simple. So check your pipes is my tip of the day!!!
