2.5 v6 Diesel engine fault

[Juliarno]

Hey guys I’m new here , just joined , I have bought a sport avant 2.5d Manual , on purchase it drove lovely , I then for peace of mind did the oil & filters …. I’ve a few concerns , it late at starting cold , so guess I need new heat plugs , it starts with a lot of black smoke , but recently that’s improved dramatically , on driving and hard acceleration I had black smoke , now that’s improved somehow , my other thought is a dribble injector , it can smooth out when I increase revs , but many times at idle , it’s seems gruff , and makes chatter that this Audi shouldn’t have … can a dribble injector make it idle rough ? Should I first get the taken out and checked , or is my problem something else > it’s a 2004 model , I hear about faulty camshafts , could it need re doing ? I paid £1400 for an unmolestered model , with good history and 134k miles
please advise , and anyone Lancashire to maybe fix my issue

 

[spartacus68]

Used to have one, on a 2001 plate. If it’s smoking, then run a can of Forte diesel conditioner straight into the fuel filter and drive it hard. Replace the filter afterwards. I know some of the later cars had camshaft issues, but regular oil changes help.

Check the return lines on the injectors too. They are known to weep. If you go down the glow plug route be careful. Run the car to temperature, and prior to that spray PlusGas on them 2-3 days before attempting the job. Use a quarter inch ratchet and deep socket. The temptation to hammer in with big tools and break one of the Bosch plugs will leave you in a world of pain and it’s a head off job to fix.

You realise the air intake manifolds and the elbow on the turbo are probably caked in soot and carbon build up? Not a difficult job to clean them, but unless you have a warm garage and this isn’t your daily driver, then I’d wait until spring. Mr Muscle, brake cleaner and a box of nitrile gloves and you can transform it.

On the rough idle side, difficult to diagnose, but if you know someone with VCDS get it scanned. When was the timing belt last done? These are notorious for faulty thermostats, so unless it sits at 90 degrees on the button, then if it’s due, replace the thermostat and water pump too, along with idler pulley.