I have just purchased a 2006 (56) Octavia Vrs estate.

The problem is the while idle the engine stutter/chug a little. This does not happen all the time and always when idle not while driving.

I have had it in the Skoda garage, to which the computer told them there was a problem with 3 of the 4 injectors/pump to which (thankfully ) were done under warranty as the last owner had them done by Skoda.

This seemed to help the problem only temporary due to the fact it has returned. And they are at a loss with what it could be due to the computer telling everything is fine.

Any help would be much appreciated

ps - Not mechanically minded so please be gentle

If it's not throwing fault codes, there are limits to what it could be.

How are the spark plugs? If they're old, try replacing them. If they're new, it's possible that you have a bad one.

It could also be an emissions control or idle stabilisation fault. In the latter case, it should be possible to check the values of the stabilistion parameters using VAGCom Computerised Diagnostics System.

Once you've eliminated the above, and if it's possible, get the engine fully warmed up and take it flat out down the autobahn for 10 minutes or so. This should clean up anything that's just dirty/carbonised.

thanks for the reply

i forgot to mention a couple of things

1. its a deisel

2. there is a smell that is not that of normal exhaust fumes (tho it has passed an emmissions test)

I'd presumed petrol, but that just means it's not the spark plugs. The other points still apply.

Does the exhaust smell of diesel fuel once the temperature guage is off the stop? If so, the problem could be the cambelt tensioner beginning to fail. What distance has it done since the cambelt was last changed?

don't see how it could be the cam belt tensioner starting to fail. if its failing and the belt jumps the timing will be out all the time. Was there not a topic on the harness going to the injectors going faulty.

Edited 11 April, 201313 yr by meta55b

DPF regen maybe?

This makes the engine be rough on idle and you normally get a funny smell?

the belt was recently changed, within around 1k miles, however it did this before and after fitting, so would not be an issue?

please, what is DPF? and how do you fix it? i have no warning lights on the dash, nor the ECU reporting any issues (so the garage tells me)

DPF is the Diesel Particluar Filter

It basically is a catalytic convertor for Diesel engines. If requires high exhaust temperatures to burn off Diesel particles and is fitted to reduce engine emissions.

To do this it does something called a regeneration and this then changes the map of the engine to increase the exhaust temperatures which is turn burns the soot produced by the engine. This causes the rough idle and often a funny smell due to the higher temps. When you drive with it during a regen cycle then it will feel like the engine is not responding that well and when stationary the engine note changes and becomes louder, when I first heard it I though the exhaust was broken

Have a look in the manual as it decribes what to do and how it works etc or search on the forum as there is loads of information on this subject. If there is a problem with the DPF you get a warning light on the dash and then there is a procedure to follow to clear it. It is well worth understanding this to avoid problems in the future.

There are 3 types of regeneration

Passive - The car will do this every 300 to 400 miles

Active - X 3 regens have failed and you have the drive the car as below

Forced - All the above has failed and you have to force the car to regen using VCDS (do not know how to do this as I am not a VCDS user)

The garage should also explain how it works but if there are no fault codes or warning light this sounds like normal operation. The passive regen will occur every 300 to 400 miles and it will attempt to complete the cycle 3 times. If the cycle cannot be completed then the DPF warning light comes on (check the manual for what this looks like) and then you have to follow a procedure of to complete the active regen i.e. running the car between 2500 and 3000 RPM for 15 to 20 mins and wait for the light to go out.

I am sure others on here will advise more if required and this is a guess based upon what you have said?

This might help explain it better, alhtough it covers the Common Rail (CR) engine type and you have tge Pump Duse (PD) but the principal is the same;

http://www.skoda.co.uk/SiteCollectionDocuments/Brochures/19246_Skoda_DPF_Leaflet_v7.pdf

Hope that helps

don't see how it could be the cam belt tensioner starting to fail. if its failing and the belt jumps the timing will be out all the time. Was there not a topic on the harness going to the injectors going faulty.

You might think that, but I've had a belt jump a tooth and then jump back. Even before that happens, if the belt is slack the timing could get part of a tooth out and then get picked up again as the tensioner re-asserts.

the belt was recently changed, within around 1k miles, however it did this before and after fitting, so would not be an issue?

My suspicion relates to the tensioner rather than the belt itself, so if the tensioner wasn't changed with the belt this would be possible. Does the invoice refer to a "timing belt kit" or just to a timing belt?

DPF is the Diesel Particluar Filter

It basically is a catalytic convertor for Diesel engines. If requires high exhaust temperatures to burn off Diesel particles and is fitted to reduce engine emissions.

To do this it does something called a regeneration and this then changes the map of the engine to increase the exhaust temperatures which is turn burns the soot produced by the engine. This causes the rough idle and often a funny smell due to the higher temps. When you drive with it during a regen cycle then it will feel like the engine is not responding that well and when stationary the engine note changes and becomes louder, when I first heard it I though the exhaust was broken

Have a look in the manual as it decribes what to do and how it works etc or search on the forum as there is loads of information on this subject. If there is a problem with the DPF you get a warning light on the dash and then there is a procedure to follow to clear it. It is well worth understanding this to avoid problems in the future.

There are 3 types of regeneration

Passive - The car will do this every 300 to 400 miles

Active - X 3 regens have failed and you have the drive the car as below

Forced - All the above has failed and you have to force the car to regen using VCDS (do not know how to do this as I am not a VCDS user)

The garage should also explain how it works but if there are no fault codes or warning light this sounds like normal operation. The passive regen will occur every 300 to 400 miles and it will attempt to complete the cycle 3 times. If the cycle cannot be completed then the DPF warning light comes on (check the manual for what this looks like) and then you have to follow a procedure of to complete the active regen i.e. running the car between 2500 and 3000 RPM for 15 to 20 mins and wait for the light to go out.

I am sure others on here will advise more if required and this is a guess based upon what you have said?

This might help explain it better, alhtough it covers the Common Rail (CR) engine type and you have tge Pump Duse (PD) but the principal is the same;

http://www.skoda.co...._Leaflet_v7.pdf

Hope that helps

yes, thankyou, this has helped in the explination of this device/thingy , however now that i understand this a lot more, the chances of it being this are slim,

due to the fact i do approx 80-90 miles of autobahn driving a day to get to work, to which i streach the car to its upper speeds (the joys of living in germany i suppose), so unless a sensor has gone? could it still be this or have i missed something ?

If it's not throwing fault codes, there are limits to what it could be.

How are the spark plugs? If they're old, try replacing them. If they're new, it's possible that you have a bad one.

It could also be an emissions control or idle stabilisation fault. In the latter case, it should be possible to check the values of the stabilistion parameters using VAGCom Computerised Diagnostics System.

Once you've eliminated the above, and if it's possible, get the engine fully warmed up and take it flat out down the autobahn for 10 minutes or so. This should clean up anything that's just dirty/carbonised.

would these items be reported via the ECU or are these items extra?

what would be the approx cost just to replace them any way?

You might think that, but I've had a belt jump a tooth and then jump back. Even before that happens, if the belt is slack the timing could get part of a tooth out and then get picked up again as the tensioner re-asserts.

My suspicion relates to the tensioner rather than the belt itself, so if the tensioner wasn't changed with the belt this would be possible. Does the invoice refer to a "timing belt kit" or just to a timing belt?

a good question well presented, i am on to the garage to confirm if it was just the belt or the belt and kit. i will let you know very soon

There is something called static timing or something like that (sure somebody will come in with it).

Basically the injector timing can be adjusted a touch to calm it down.

It can also be caused by a cambelt change where it's very slightly out.

Sure there are other explanations, but with it being a PD170, I could imagine that DPF regen issues could be a part of it.

Unless it's the static timing, it's almost certainly not timing, and I think we can rule out DPF issues too, on a car that's spending 20 minutes twice a day at about 120mph. If it was base timing, I'd suspect there being a good chance of a piston to valve collision!

a good question well presented, i am on to the garage to confirm if it was just the belt or the belt and kit. i will let you know very soon

been told it was just the belt

If it was the belt and they didn't put a new tensioner on it, then I'd be looking at getting it replaced by them.

easier said then done, as i have the car in Germany and got it from Peterborough.

is that an easy job to do or is it another pain in the ass?

This will be related to the injector change.

Lot's of documented issues on here as a result of the Skoda recall on the injectors on the PD170.

Lumpy idle, poor cold starting, engine cutting out, fuel mixing with the engine oil, unusual exhaust fumes/smells, increased fuel consumption, excessive DPF regens etc.

I'd recommend removing the injectors, replacing the seals and reseating them correctly.

Some bed time reading for you...

http://www.briskoda.net/forums/topic/189502-cold-start-problems-with-a-pd-tdi-170/page__hl__%20injector%20%20recall

If you are still awake after that this will finish you off!

http://www.briskoda.net/forums/topic/197422-vag-170-ps-diesel-injector-failures-vosa-action/page__hl__%20injector%20%20recall

ok 3 of the 4 (i believe) injectors were replaced, now am i being naive in thinking they replaced the seals too?

also having reading your post there (cold start) i also have this issued, first thing in the morning, but hen no porblems for the rest of the day, is this related or ?

it does not happen all the time, and at the moment cant tell if there is a specific time of day it happens as it has happened any time, ( i am going to start keeping a log)

there are other things that ppl are suggesting but just not sure

emissions control

cam belt tensioner

camshaft sensore

DPF

static timing

am just not mechanically minded enough to fathom any of it, lol, am just a mere driver that does what he needs to do.

it just worries me that the skoda garage them selfs are at a lost and am having to do this :think:

Edited 11 April, 201313 yr by sidney4003

I've been where you are now.

It took me 6 months of hassle with a couple of local dealers, Skoda UK and Skoda Technical Support in the Czech Republic.

I even made video's of the cold starting (in the video above). I left it at the dealers overnight for them to witness the starting issue and rough idle.

Never any fault codes, the dealers adjusted the timing, replaced the fuel filter housing, ran countless diagnostic sessions, removed and cleaned the glowplugs - the list is endless.

In the end they removed the injectors and realised that they hadn't been fitted quite right. Diesel was leaking past the seals. The injectors were removed and reseated and things slowly improved, but it took some time. It wasn't an instant fix.

I'd enquire as to why only three of the injectors were replaced. All four should have been changed under the recall unless the car had already broken down previously due to an injector failure before the recall was announced?

Depending on when the recall was carried out then the injector wiring loom should also have been changed, as well as the seals.

thank you. it can be so frustrating lol. yours and everyone's help is much appropriated

i believe that they were all replaced by the recall under the old owner. this is why i have had 3 of them replaced under warranty as they were under 2 years old. and they were the ones they believed were faulty.

i will however investigate regarding the wiring loom, also will ask them to confirm seals and seating again of the injectors. its worth a go, they are doing a complete service at the same time so you never know.

i will let you know, but it will not be going in until next Friday due to work commitments,

again thank you

easier said then done, as i have the car in Germany and got it from Peterborough.

is that an easy job to do or is it another pain in the ass?

Would you feel confident about doing a job that involves supporting the engine and removing one of the mountings? If not, then a cambelt change (and I would put a new belt in if I needed to change the tensioner) isn't a DIY job for you.

I'd investigate the injector seal. It wouldn't surprise me if people used the old ones being lazy.

I almost blew my top at a guy in a garage, after I supplied new bolts for everything and he said after yeah I didn't need them.

Some were stretch bolts, so I made him go and change every one before I'd pay.

Remember to keep an eye on your oil level.

Small amounts of diesel seeping passed the injector seals won't make itself immediately known, however over a few hundred miles you should notice it creeping up.

I do 900 miles a week so a fews weeks after the injector change I quickly knew something was wrong.

Shame Skoda didn't.