We have a 1.4 diesel SEL. I've never experienced it directly, but my wife has had a few times when the car doesn't slow when you take your foot off the pedal. It's only at like 30MPH and it doesn't take off, just doesn't slow down. I was in the car once so know it's actually happening.

 

Cruise control is off so its not that. Some years ago we had a roomy that did this and the throttle pedal was replaced which fixed it. Anyone seen this on a Furby Mk3?

Is it that its being pulled along by the idle speed?

Diesels have a bit higher idle than petrol.

I noticed in an Octavia diesel, it will run along in first with my feet off the pedals just on idle, its that high.

Quite good in a queue, that might be what she is experiencing.

Especially if it's doing an active dpf regen with raised idle speed.

Sound like anti stall and is present on most VW designed Diesel engines of late.

Change down a gear. Your wife is still possibly in 4th- which is too high for thirty in town.

Yes anti stall thats what its called.

Although I was driving this new Octavia up a slight incline, car in front slowed to turn off, I put it in 2nd to carry on, pressed the accelerator to go, it coughed and then stalled.

So I well and truly beat that.

My 1.2 petrol would have pulled away, but not the diesel, it needed 1st. Suprised me a bit.

From what I've heard a friend with a newish Mondy TDI say, this is now the way of things, also, if you stepped out of an older 1.4 16V petrol engined Fabia and then into one with a 1.2TSI, you would find this quite a bit before you adjusted to the way things need to be - well that is what I've noticed with wife's Polo 1.2TSI 110PS, sometimes I expect a bit too much from it, and it lets me know - not by stalling, but by being a bit reluctant!

Edited 31 December, 20169 yr by rum4mo

Thanks for the replies. If I'm honest I'd wondered if it was being in too high a gear. On the rooster it was definitely the pedal but I was convinced they'd have fixed that issue.

Change down a gear. Your wife is still possibly in 4th- which is too high for thirty in town.

To high a gear? I even used 6th gear on my petrol i30 around town at 30mph. Not a problem as it was still doing at least 1400 rpm. All my past cars I would also be in 5th gear (5 speed box). I don't understand why people think top gear is only for 50 mph plus but then moan of poor mpg. You should not be driving along at 30mph in 3rd gear unless still accelerating as you would be doing more like 2000rpm plus, you are just increasing wear and fuel consumption.

Edited 2 January, 20179 yr by POWYSWALES

POWYSWALES

I have no wish to enter into a points scoring session with you, HOWEVER,............

 

1 - You have to keep in mind that the diesel fabia is very high geared - if you had a diesel Fabia with a manual 5 speed box, you would then see that at 30 in 4th, the revs are quite low and getting near to the anti stall parameter becoming active.

 

2 - Using a i30 petrol that does 1400 rpm in 6th at 30 miles per hour (?) has no relevance in this case.

 

3 - If you had access to the automotive industry design and R&D departments, you would become aware that most manufacturers centre the ratio of third gears to suit town driving, and this has been the case for many years.

 

4 - flogging away a modern diesel at low revs around town is just asking for trouble - diesels are no longer ideal town cars, they never really attain full working temperature and as a consequence start to experience very expensive egr and dpf problems.

 

5 - I note that you are using a DSG Skoda - this does not have the same characteristics as a manually geared car.

 

Driving along in third relieves the load placed upon the car, higher gears impose a greater load - and lets face it in town it is  mostly start/stop driving anyway.

Edited 2 January, 20179 yr by 2ndskoda

To high a gear? I even used 6th gear on my petrol i30 around town at 30mph. Not a problem as it was still doing at least 1400 rpm. All my past cars I would also be in 5th gear (5 speed box). I don't understand why people think top gear is only for 50 mph plus but then moan of poor mpg. You should not be driving along at 30mph in 3rd gear unless still accelerating as you would be doing more like 2000rpm plus, you are just increasing wear and fuel consumption.

 

Selecting too higher gear too early increases fuel consumption and lowers efficiency, especially on diesels. 5th and 6th gears on manual shifts are for higher speeds and not for town work. Your dsg will adopt a different gear compared to a manual box, just as my dsg petrol engined Fabia does, compared to a manual car. It can do that because it knows when to instantly change if you put load on the engine. My dsg car will not go beyond 4th gear at 30mph however, and maybe 5th gear on a slight downhill run, and only adopting 7th gear at 40mph or above. The OP is experiencing a slight surge or high idling due to the factors being mentioned above. On the 3 cylinder engines this is normal and more noticeable than on the 1.6 four cylinder unit in my experience. Even having the fan blower going can make the engine run faster at idle and when moving slowly so it does require some initial getting used to, what with anti-stall as well etc. 

The thing is now with Euro 5 & Euro 6 Petrol or Diesels and 6 or 7 speed DSG they are quite happy to go to 4th or 5th as you get to 40-50 mph as you use the throttle 

then go to 6th or 7th and drive economically.

If needs the gears drop just not often to 1st. That is in 'D'.

 

As to petrol & diesel manuals i have no idea, never having driven one.

3rd is right at 30 for some cars, for others it's 4th. My Fabia, with the 1.2 TSI 90 and the 5-speed manual box, likes 4th when at a steady 30 mph on the flat. The gear recommendation thing in the Maxi-DOT suggests 4th. TBH it feels like the car could really do with the 6-speed box the 110 version gets, as 5th is a little too high IMO. 

 

With the 1.4 TDIs, I'm guessing that their 5-speed boxes are set up far higher than the ones in the TSI, so it wouldn't surprise me at all if 3rd was the optimum gear for them at 30. What does the Maxi-DOT say? Is it recommending 3rd or recommending changing up?

5th at 40MPH in ours is OK, but only just above 1000RPM, and is also based on the GSI in the pack. I suspect 30MPH would be a problem, and may be the actual problem. 

So it did it to me today, when I left it in 5th and the speed dropped. I'm no sure its the antistall as suggested. It was fine until the RPM dropped to 1000 on a cold engine.

It also depends on what other electronics you have switched on at the time too. If using heated this that and the other, with the blower on, it will affect the idle speed and most likely will bring in anti-stall quite early. Leaving it in 5th gear on a modern diesel at 1000 rpm (not desireable) will cause this issue intermittently, again it's often dependent on the accessories you are using and the engine revs. Modern diesels like to rev a bit more than diesels of old for lots of reasons. 

So it did it to me today, when I left it in 5th and the speed dropped. I'm no sure its the antistall as suggested. It was fine until the RPM dropped to 1000 on a cold engine.

 

Correct me if I have misinterpreted what you said? BUT did you say you were doing 1000rpm in 5th gear !!!!!!!!!!!!!!!!!!  If that is the case - what MPH did that equate to?

 

That would be a big NO NO.  Apologies if I did not really understand what you said - please clarify.

Correct me if I have misinterpreted what you said? BUT did you say you were doing 1000rpm in 5th gear !!!!!!!!!!!!!!!!!!  If that is the case - what MPH did that equate to?

 

That would be a big NO NO.  Apologies if I did not really understand what you said - please clarify.

Yes. 1000RPM in 5th, about 35MPH. Although its too low and I wouldn't normally do it (I was trying to reproduce the issue) the GSI did not suggest downshifting.

You have put such a high load on the drive train that the antistall and diesel torque just could not overcome the stress you applied in this instance.

You seem to be resisting the clear points made throughout this theme by many others.

Many will tell you to take no notice of the suggested info 're gears on the speedo cluster. If you want to get the best from a modern diesel drive it in a more spirited manner- driving around like Miss Daisy will kill a modern diesel engine!

Please note I have had both a pd90 tdi and a cr90 tdi fabia, both had the characteristics that you describe

Edited 5 January, 20179 yr by 2ndskoda

Just to be clear. There was almost zero load on the drivetrain, as the throttle was completely released. 

 

I'm not resisting any points, I agreed that it was most likely the correct explanation, and have now proved it. If you read the start of the thread I'd never experienced the issue directly so was unable to say what RPM it happened at, and I have experienced an actual sticking pedal in the past (which I proved with VCDS by the way). Driving a modern diesel gently will NOT kill it. Sure it needs to have a run to help with DPF regeneration, but actually that happens best with fairly small 'throttle openings' and a nice constant speed. 

Ideally, you don't want a 'regeneration' to be triggered by the ecu just because you drive your diesel on light throttle settings. It causes extra fuel to be injected, and is less good for the dpf and engine generally. It's best to use plenty of revs and throttle at various opportunities to allow natural cleaning of the dpf by getting it nice and hot with plenty of internal pressure to clear and clean it. In general, if you are getting regens triggering, you are probably not driving it hard enough or using the car enough at dual carriageway/motorway speeds. The modern diesel engine generally likes to be driven much harder than diesels of old as the piston speeds are lower and less stressed, so carbon can build up more easily in the combustion chambers and on the valves. It also helps the oil to stay at optimum temperature, all important in helping to keep the oil clean especially in winter. But it sounds like you have the answer to your query! Well done lowedb and a good post. 

Edited 5 January, 20179 yr by Estate Man