Thanks for that. 1st Audi and very disappointed. Over 22 weeks at the dealers there has been a new cylinder head, new high pressure pump, new tank pumps, ECU wiped and reprogrammed by Audi via the internet from Germany, idle speed increased and other things I can't remember. Getting a bit pi**ed off although they lend me brilliant cars and have extended my warranty by another year.

Why do peole in the UK think that Audi is something special they are only Skodas with a fancy badge and people pay a massive premium.If you want a class German product then it has to be Porsche, DB or BMW.

Are you kidding, DB with their poor build quality issues and BMW who force you to use run-flat tyres and then the alloys crack and need replacing, or the BMW diesels which such the air butterfly into the engine. Audi's arent perfect but you can find the odd bad story from any marque.

Thank you to those who have replied. The high pressure pump has been replaced as has the 2 tank pumps. I am leaning towards a single injector now as it seems from memory that it runs poor as if one cylinder is not running right for a short while. Thought I was buying some reliability/luxury last September. I must have been not right that day. Regards to all.

Ours is back in again. Since January the total time in the dealers is 28 weeks. This time it is back to the dealer I bought it from but is further away than my local one. They have found a faulty injector and worn injector rockers. It is ready to pick up and we will see how we get on after we collect it on Friday. Good luck with yours.

I checked history - the dealer does not appear to have replaced the injector rockers. Surely though, wear would cause a permanent problem, rather than an intermittent one? Also, what is PD oil? My car has only had one service - at 16K miles/2 years. Its now done 30K but is not yet requesting the next service. Is that an issue? Cheers

An update for those who may be affected. After following the threads last year about faulty injectors on these cars Audi reluctantly put a new set in with the wiring loom last autumn. The car would still be a b**** to start at times when cold and not that smooth to drive with its lag and lurch engine response. An independant told me that it was time to change the cam belt and I agreed as I thought it was time to do it. That was done early last week and I now have a different car. It is quieter, smoother, much more pleasurable and easy to drive. Obviously the valve timing has been out. This is a worry because it must have been out before Audi changed the cylinder head. Why wasn't it corrected when it was replaced?The car starts well now. I have been puzzled that correcting the valve timing has made such a difference. I used to run a vernier cam pulley on my short oval racing engine and new what could happen by adjustment. The penny dropped when I realised that the injectors were operated from one of the camshafts and concluded that not only was the valve timing out but the injection timing. This has cost Audi thousands as a result of incompetence at their dealers. Sorry lads, had to get it off my chest. Regards.

The injection timing on these engines is quite properly derived from the crankshaft via a variable reluctance transducer at the flywheel end. This gives minimal perturbation of the speed signal which will lead to poor governing. The phase relationship of the unit injector cam is largely immaterial so long as pressurised fuel is avaiable throughout the engine map.

The cam timing relative to the crank ("KW" in VAG speak) is adjustable via a slotted camwheel/hub assembly and should be set correctly when the belt or cylinder head is changed. An incorrect setting will degrade engine performance primarily due to incorrect valve timing although in extreme cases fuelling will be incorrect at timing limits. The correct setting can be verified via the diagnostic port without opening the bonnet.

These engines are sophisticated units which will not tolerate poor maintenance. Your experiences and observations suggest to me that attention to this engine has not been of the best.

It is my view that VAG did the PD engine no favours whatsoever when they stopped using the electromagnetically actuated Bosch injectors.

659.

Thank you 659-they are certainly complicated. Although my car runs far better since it has had its timing belt changed it is still difficult to start when cold. I believe that there is a glowplug problem despite the garge where the belt was done saying they could find no fault when they plugged their computer in. If the glowplug control unit was faulty would this show up? How can I test what is happening at the glowplug please? I am thinking along the lines of attaching a small cable to one plug which would then have its supply reattached and connecting my voltmeter to this cable with the negative to earth. This would then show the voltage applied and duration. Would this upset the computer and then record a fault? Of course I do not want this to happen. I have a good car spoiled. Regards.

Thank you for your reply. The items I listed that were changed/attented to were all as a result of my complaint of poor starting. I tried it this morning with the air con turned off with no difference. Regards,

Edited by paulc924 on 22/01/2013 at 17:49