Dundeeguy wrote:Fuel is ok. Car has had this fault for a few months.
Arjen, was your Seat not fitted with the PD engine, where by it will open the injectors via the camshaft?? We don't have the wps I'm afraid. It will go on the shopping list!
Do you know if there has been any history of misfueling with this car? It could be that it happened roughly a "few months" ago.... White smoke would point towards unburned fuel, usually as a consequence of EGR not closing off properly, but often down to poor injector spray pattern or poor spray pressure or poor spray duration. A pressure sensor in the fuel supply and the fuel return system would rule-out whether the engine is receiving (and returning) fuel from the tank at the correct pressure. These can easily lead to injector spray problems. A check with leak-off equipment might show-up if any of the injectors is unable to return fuel back to the low-pressure system (fuel pressure will be high at the spill port). It might be that No.4 injector is genuinely duff, but it's worth making sure that the feed to/from that injector is good.
Have you checked the cam-timing and lobe-heights, just to be sure that the injectors are pumping up to pressure and at the right time? I think that arjen makes a good point here.