Help - Intermittent problems with acceleration/power delivery - 2011 Octavia vrs cr tdi

[Pabs]

Hey folks,

 

I have a problem with my 2011 Octavia vrs CR/tdi that has occurred a couple of times now and I've just contacted Skoda to get it booked in asap.

Symptoms:

 

• When accelerating, serious lack of power and very slow acceleration, noticed at various speeds. (e.g. 2nd gear, 20-40mph, 4th gear 50-70mph)
• Taking foot off accelerator and re-applying power seems to resolve the problem (at least it has on the last 2 occurrances)
• Car was idling at just over 1000rpm, normally idles at 750rpm. (I know this could be a DPF regen, but this high idle lasted a good 15 miles on my journey to work. I did not notice the fans running)
• No error lights on dash or diagnostics tool.

 

My commutes are 30 mile A-road/dual carriageways. Car has 30k on the clock, and is still within warranty. (1 month left)

 

 

The previous owner of the car reported this problem when it was only 6months old. Skoda took ages to resolve the issue, but apparently it was turbo actuator sticking or something?

 

Do Diesels have throttle-bodies, and if so could this be sticking?

 

If you can shed any light it would be great! Thanks

[Pabs]

Also, the car power never seems to hit until just under 2500rpm. I understand this is pretty normal for a diesel, but thought I'd mention it in case you didn't agree.

[softscoop]

Also, the car power never seems to hit until just under 2500rpm. I understand this is pretty normal for a diesel, but thought I'd mention it in case you didn't agree.

That's not normal. A diesel usually has most of the power at the bottom end.

 

A sticking turbo actuator would describe the power problems as it's probably not providing boost. Taking your foot off and back on will probably provoke it into working the 2nd request.

 

Get Skoda to look at it whilst its still under warranty.

 

FIY diesels do not have a throttle body and simply take in all the available air from the intake. The amount of air is controlled through the amount of boost the turbo makes. This is why you don't need a blow off valve as there is no throttle plate that can prevent the charged air going nowhere.

 

On a non-turbo diesel the only thing that's controlled is the amount of fuel injected.

 

Most diesels have an anti-shudder valve which looks like a throttle body, but this will close on engine shutdown to provide a clean stall, rather than the engine shuddering to a stop.

[Pabs]

Thanks for the informative reply

 

When I say most of the power is at just under 2500rpm, that's when I feel the big boost hit - the bit that pushes me back in the chair, so to speak. If that's not normal then I definately need to get the car looked at asap :(

[softscoop]

Whilst at Skoda see if you can drive another vRS with the same engine to see how they compare.

[Pabs]

Good idea, if they have one in ( don't seem to hang around long)

[Pabs]

Today car is driving normally again - well at least I didn't have any loss of power. Still get a big kick at around 2200rpm-2500rpm, I'm told this should be a bit lower at ~ 1900rpm. Is that correct?

Can the turbo actuator be adjusted? I seem to recall this was possible on an older car I had - perhaps it's sticking and not set correctly?

 

Or I could just be guessing and making incorrect statements... too early in the morning to think straight haha!

[Pabs]

Folks, am I right in reading that a dpf regen could occur ever 3-400 miles?

Today I got home and engine fans running after switch off and the nasty hot smell that indicates a regen, and the drive home was really naff - at least 10 miles of poor power delivery, lumpy acceleration and in 2nd gear almost no power to pull away from a junction safely.

I'm trying to determine what performance impact the dpf regen would normally have - idling at 1000rpm all seems indicative of a regen but I am not enjoying the performance issues, especially as it occurred whilst I was in stop/start traffic and junctions around town...

Thx

Sent from my iPad using Tapatalk

[Pabs]

Block 108: 30ml oil ash volume, 6.6 particle filter (spec) 0.0 particle filter (actual)

Successful regens: 0

Requested regens: 1

Distance/fuel/time since last regen: all 0

I'm unsure why successful regens = 0? Car has almost 32.5k on the clock.

Thanks!!

Sent from my iPad using Tapatalk

[eddh]

was the coil light on when you had the problems , I had a coil light (pre heat light) on and flashing and that was a turbo actuator sticking fixed under warranty  

[Pabs]

No - no errors on dash at all. Just ridiculously crap power delivery.

As above, my journeys are 30 miles each mostly A roads around 50-60mph.

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[Pabs]

Here are some vcds stats from today:

 

Stats from 10/11/2014 (32564miles) - 52400KM

Oil Ash Volume    30ml
Particle Filter Carbon Mass (spec) 6.6
Particle Filter Carbon Mass (act) 0.0
Time elapsed since Regeneration  0.0
Driven Distance since Regeneration 0.0
Fule consumption since Regeneration 0.0L
Requested Regens   1.0
Successful Regens   0.0
Group 105 Bin Bits   00000000
Group 070.1 Bin Bits    101111111
Group 070.2 Bin Bits   00000001

 

 

And from 1st October 2014 (although not as complete as above)

 

Stats from 1/10/2014
Oil Ash Volume    30ml
Particle Filter Carbon Mass (spec) 5.4
Particle Filter Carbon Mass (act) 0.0
Group 105 Bin Bits   00000000
Requested Regens   1.0

 

So definitely looks like it was a regen tonight. Whether or not it completed I don't know? (Fans etc running when I parked up, for probably 3-5mins or so?)

When a DPF is performing regen, and when doing town driving, is the power loss/hesitation/acceleration issue really that noticeable?

 

Thanks folks
 

[littleade]

If the tickover was higher a than normal at circa 1000 rpm and the fans started up after you switched the engine off then you have interupted an active regen. It will most likely start another the next time your car reaches full operating temperature and providing you allow it time to do its thing it'll complete it as normal so is nothing to worry about. I've never noticed a difference in performance when mines doing a regen though.

edit: noticed your question on milage between regens. It will perform one when the soot reaches a certain level or you've done around 600 miles which ever comes first. A number of factors including how you drive the car and the type of journeys you do will affect the speed at which the soot builds up as once up to temperature the dpf will get rid of some through normal passive regeneration. If you search in tne octy 2 section I've posted a link to a document that explains the dpf in detail but I'm on my tablet so don't have the link to hand

[Pabs]

That's what I thought, thanks.

Problem I'm worried about is the performance impact - I drove for circa 10 miles knowing that the idling rpm was higher (and assumed it was doing a regen) and every time I pulled away from a junction and got to 2nd gear there was little to no power/acceleration. In other gears it appeared to accelerate better, but sometimes it was very lumpy/juddery...?

 

Skoda couldn't find the fault - mind you they only did a .4 mile test drive!!! I'm half tempted to just turn up whilst it's occurring and see if a mechanic is available to jump in the car and experience it but I guarantee I won't be anywhere near my Skoda garage when it happens :(

 

I wonder if I could ask them to force a regen and take it for a drive - and see if it occurs then as well?

 

I know one thing - starting to regret getting a diesel and certainly gutted that the MOT law now states that it must remain installed....

[littleade]

Sounds like you do have something going on when its doing a regen. The increase tickover is the tell tale sign, but it only really shows up when your stationary as the anti stall that increases it to 900 rpm while your moving can mask it. If its going to do another one soon which seems likely you'll be able to see if its happening again. If it does I'd reset the trip so you know when the last one was then go in and see the dealer and ask what they suggest as they would normally charge for a forced regen if it was because the lights came on, but might reduce or wave this as they will no doubt charge you a diagnostic fee. You'd need to ask if they can drive the car while a forced regen is taking place to see if what you suggest is possible (because I don't know!) Looks like you're unlucky because I've not seen any real issues posted before except the odd sensor problem. Good luck.

The upside is that once you've sorted it the tdi will be worth more than a similar age/milage tsi so you could always look to change?

[DanialA11]

I know one thing - starting to regret getting a diesel and certainly gutted that the MOT law now states that it must remain installed....

You can get the dpf removed and leave the casing as the mot is only a visual inspection

If u get the section cut out and install a streight pipe like a de cat then it will fail mot

[Pabs]

So, turns out I am right, and there is an issue. Had it on a rollers yesterday, and can clearly see the weird power delivery - it's almost like something switches on/closes at about 2300rpm and the power comes on thick and fast. Will try and upload the graph later.

It still makes 174bhp standard so it's giving what it should - but it's how it gets there that's odd.

Egr doesn't seem to be stuck and the actuator voltages seem about right..

This is all well beyond my understanding, but a few areas have been suggested:

Remove and inspect EGR

Check cam timing

This is really annoying as no fault codes are thrown. If a DPF regen is in progress and I stick it in a high gear low revs it doesn't want to pull at all, sometimes judders as it tries to accelerate.

Really not sure what to think or where to go next.. If you have seen this before or have any ideas they'd be much appreciated!

[trundlenut]

Have you tried logging requested and actual boost?

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[Pabs]

This was logged during the power runs, and we could see it was requesting the boost but not actually achieving it in the lower revs. Will upload the power run graph or at least the section showing the issue.

[Pabs]

Hopefully this upload works... This is between 2k and 2.5k rpm

Edited 23 December, 2014 by Pabs

[Pabs]

So trying to list the symptoms thus far:

Power delivery similar to turbo-lag. From any speed/rpm foot to the floor, a good 2-4 seconds before any real power is delivered.

When active DPF regen in progress (high idle rpm sat in traffic etc) notice a severe power problem, no pull in 2nd gear and high gears acceleration is sometimes met with a judder and no power whatsoever.

Power curve shown above - huge spike between 2300/2500rpm rather than the smooth curve as expected.

DPF regens seem to be occurring every 250-300 miles. (Logged over a few months) current ash content 30ml/g (can't remember units)

Car still delivers max power/torque as expected, but it's how it gets there that bothers me.

No errors on VCDS.

Voltages on turbo actuator are reporting ok.

Manual test of egr via vac line appears to open/close egr ok (can hear it moving)

Skoda CS are useless. Didn't want to help or know at all. Test drove for 0.4 miles before giving up with no fault found. Skoda HO ignored my issue, then refused to help as the warranty was running out and I didn't purchase the car from brand new. Refused to offer extended warranty too, which was interesting!!

Really gutted as I thought Skoda were good - but my experiences have shown that of VW and SEAT to far outshine Skoda. Looks like I am on my own on this one with my trusty Indy garage, but expect it to cost me £££ to figure out and resolve.

:(

[DanialA11]

Try this won't cosy you anything so why not seen it on.another post

Edited 26 December, 2014 by DanialA11

[Pabs]

Car is going to have to get booked in I think - no real progress here :(

Hope it doesn't work out too difficult or expensive to fix.

[Pabs]

So many things on google, all sounding very complicated and no definitive answers.

 

Full RR graph attached to this post, you can clearly see the spike between 2-2.5krpm.

During DPF Active regen performance is quite poor as well. Perhaps a fuel sensor/pressure issue? Don't want to guess though.

 

Still no errors on VAG-COM, DPF seems to regen around every 250 miles which is apparently normal behaviour. DPF ash level etc all ok, 30ml and the car has 33k on the clock so this is about right. (Again based on research online)

 

Car is booked in next week, so fingers crossed something can be found!

 

If anyone has any pointers or good tips then feel free to post them up

[tuono01]

What was the outcome of the above? My car has started to judder once into second and third gear, as if I was a learner, then work properly again. This caught the mrs out today so need to figure out the cause.