Re: 156 2.4 JTD Running bad :(
You've probably got a split boost pipe, meaning the positive boost produced by your turbo is not getting to the engine as its leaking out somewhere. Your engine therefore is not getting enough air, meaning that it cannot fully burn the diesel causing bad black smoke.
First place I think you should look is the pipe you see upon opening the bonnet, it goes from your engine over and across the battery and down into the wing, into the intercooler. Check this for splits on the underside, at the join to the engine and on the long stretch down into the wing, where it joins the intercooler. If its not this, it could be your pipe between the turbo and the intercooler, you'll need to go under the car to check it.
3rd possibility is the intercooler itself is leaking air. But from what you've described, the engine is getting less air than the MAF is recording flowing past it, so the likely cause is an air leak somewhere after your MAF but before the inlet manifold. Remember the turbo is creating positive pressure, so if there is any splits the air will rush out like a balloon with a hole in it.
- UK's leading independent Alfa Romeo specialist with branches in Bedfordshire, Cumbria & Dorset
Wizard Exhaust systems available here
Tel: 01768 879 171