Audi A3 TDI 170 - Poor Starting - paulc924

I have one of these that has intermittant poor starting. It will fire then stop when the key is released. On the second go it will fire then run rough for a few seconds. For the rest of the day the car will be fine. At other times it is o.k.. The car has been back to the dealers for many weeks and has loads of work done. Without going into too much detail about what has been done, has anybody had similar problems? If so, what sorted it please? Regards,

Audi A3 TDI 170 - Poor Starting - top-mechanic

hi sounds like 1 of 2 things, glow plugs not working but a garage should of illiminated this so i would espect the second diesel running back due too a leak possible leak offs, return valve on filter o rings start from injectors and work back,all so what work has all ready been done

Audi A3 TDI 170 - Poor Starting - paulc924

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.

Audi A3 TDI 170 - Poor Starting - Collos25

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.

Audi A3 TDI 170 - Poor Starting - Roly93

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.

Audi A3 TDI 170 - Poor Starting - Railroad.

And there really isn't much wrong with Skoda's either. Just the other day my local radio station listed the top ten cars in order of realiabilty based on maintenance and service. The best was Daihatsu, and the other nine were all Japanese or Korean. Skoda came 12th, Ford 15th, VW 20th, Vauxhall 27th and Renault 30th. None of that entirely surprises me.....

Audi A3 TDI 170 - Poor Starting - mastertechGeoff

Sounds like it may be the fuel pump in the tank, the whole fuel system is suspect on this model and is plagued with injector and pump problems, if it has had petrol put in by accident previously this sort of effect can happen as it can damage either the front or rear fuel pumps causing swarf to enter the system and damage the pump. I would be surprised if heater plugs were the cause as they would illuminate the engine managment light. Be careful which fuel you use also as the better the quality the better the Audi's will run.

Audi A3 TDI 170 - Poor Starting - paulc924

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.

Audi A3 TDI 170 - Poor Starting - IanWB

I have a A3 TDI 170, May 2007 (07 plate). 30,000 miles now. I have owned it since new. In A year ago it began to exhibit 'misfire' (lumpy idle speed, engine wobbles about at tickover, surges and baulks when cruising on light throttle) intermittently. In Feb 2010 it refused to start for 3-4 goes and when it did it ran on 2 then 3 cylinders for a few seconds. Then it was fine. Between March and May, the Audi dealer replaced the cylinder head (they said it was leaking water), the injector seals, the inlet manifold (something was loose apparently) and several other bits. I never had the starting problem again (until now) but they did marginally improved the 'misfire'. I stopped using BP Ultimate diesel and that helped a lot. Now just the week, the poor starting is back - suddenly.

Audi A3 TDI 170 - Poor Starting - paulc924

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.

Audi A3 TDI 170 - Poor Starting - bimmer-driver

Worn injector rockers on these is usually due to being run on normal oil. PD oil is vital.

Audi A3 TDI 170 - Poor Starting - IanWB

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

Audi A3 TDI 170 - Poor Starting - Collos25

The problem is that they set them for fleet users so they have minimal costs, when they are three years old and disposed off having been badly serviced they do not care they are out of warranty and sum poor sucker will then pick up the expensive bills in its later life.Like many VAG units in Germany where this problem is prevelant the solution seems to be new injectors, new high pressure pump a rewriting of the electronic script and if that does not work a complete new engine.They might be the top selling car in Germany but they seem to produce the most lemons even coming way behind Dacia/Renault in the reliability tables.

Audi A3 TDI 170 - Poor Starting - paulc924

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.

Audi A3 TDI 170 - Poor Starting - unthrottled

he 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.

Yup. Changing the valve by a couple of degrees doesn't make a lot of difference (unless you have a clearance issue!). But changing the injection timing by a couple of degrees makes a big difference. You have to be very careful about locking the cam wheel when doing a belt change.

Audi A3 TDI 170 - Poor Starting - 659FBE

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.

Audi A3 TDI 170 - Poor Starting - 659FBE

Bedtime reading:

www.volkspage.net/technik/ssp/ssp/SSP_352.pdf

659.

Audi A3 TDI 170 - Poor Starting - paulc924

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.

Audi A3 TDI 170 - Poor Starting - countryroads

Really, you need to seek out someone with VCDS (VagCom) to get things like the torsion value cam to crank, injector stabilisation values etc electronically. They are easy to take apart but thats it, it worries me the cylinder head has been off, as this gives scope for alot of things to be wrong if not fitted back correctly.

The glow plugs play a very small role in these engines unless it is very cold indeed.

Does it behave differently if you start it with the air con switched on..

Edited by countryroads on 21/01/2013 at 09:35

Audi A3 TDI 170 - Poor Starting - paulc924

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

Audi A3 TDI 170 - Poor Starting - paulc924

For those who are interested, I know that it has been some time but the following happened about a year ago. The low coolant light kept coming on and I had to top up coolant. Went to a different garage and a leaking water pump was diagnosed. The current one (with timing belt and ancilliary belt and idlers) hadn't been on 2 years but outside of warranty. This garage replaced the pump and put a new belt on. I drove home a totally different car again. It was much smoother and probably the engine it should have been all along. I spoke to the technician who carried out the work and he told me that the timing had been out. So to recap, wrong timing from the dealer after a head change and then wrong from a specialist. This isn't good. The car is beautiful drive but guess what? Intermittent poor starting when cold and the odd misfire when driving. What is going on with this car?

 

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