VRs diesel 'fade'?

[mangoletse]

Just wondering if anyone else has experienced this - seems to happen when driving in 4th/5th at 40mph, engine in comfortable revs etc. Car has done about 1500 miles so far. I did wonder at first if it was DPF regen but I'm not so sure the longer I keep feeling it.

Put simply, the engine just seems to lose power for a very brief moment, power drops so it feels like the car has just held back slightly, then just carries on as before. I guess on older engines if have put it down to a tiny fuel blockage maybe.

Not had it back to the dealer yet, although I will, although I guess it'd be hard to recreate on demand. Just wondered if its normal for a new engine, early stages of lots of regens etc..,

[Mence]

I have felt similar but wasn't sure if it was the DSG arguing with itself over which gear it should be in.

Will monitor things more closely and report back.

It's only happened a handful of times in 6000 miles so it might take a while...

[littleade]

My mk2 sometimes does this sort if thing on a trailing throttle about 2000 rpm, normally when going down a slight hill. when I press the accelerator gently nothing happens for a brief moment, then it accelerates as usual. is this what you're experiencing? If so I was told it's a common occurance and nothing to worry about.

[Neily03]

IMO 5th gear is too high for 40mph....

[bigkevyorks]

Agree with Neily03, my new VRS hatch diesel DSG (5,700 miles) drops down to 4th gear below 40mph. Shouldn't be the DPF at that mileage, nor should it be a fuel blockage. I'd get it checked out by a Techie at the dealers to be on the safe side.

[themanwithnoaim]

Is it a DSG in Eco mode issue

[bigkevyorks]

Agree with Neily03, my new VRS Diesel DSG Hatch (5,900 miles) drops down to 4th gear below 40mph. Shouldn't be the DPF at that mileaqge, nor should it be a fuel blockage, it's practically brand new. To be on the safe side I'd get it checked out by a Techie at your dealership just in case.

[mangoletse]

I will get it checked, thanks for replies. Mines a manual, and tbh I seem to know not to use 5th on the way in to work but seem to on the drive home (and there are two 'spots' where this seems to happen. I'll ignore the maxi dot for a while, stay in 4th and report back... Spot 1 is uphill but (iirc) trailing the throttle to decide whether car in front will turn right (and hence switch lanes and give it a bit of boot). Spot 2 is flat, clear 40 but can go a bit slow due to junctions ahead. Food for thought!

[Simmyh]

Mines doing the same but I get it in 3rd,4th,5th and 6th I'm going to get it checked at the dealers

[Griffenfeldt]

I used to have that same problem with my previous diesel engine. It never happend after i learned to give it a beating now and then. If you drive your diesel enging like you're driving miss Daisy this is a problem that will continue.

[1600cr]

I've read the comments over and over but it's still not 100% clear are we talking about being on a steadyish throttle, maybe a little bit of load and when lifting the throttle slightly it feels like it's cutting off the fuel ?

[snala]

Yes mine does it every now and then too. Feels like you have slipped off the accelerator pedal and then started pushing again. Sometimes its the regen kicking in but others its not. Seems sporadic but slightly concerning because it doesn't feel right.

[Neily03]

Turbo lag?

[6xsteve]

I get this regular as clockwork. Referring to dealership as they think it may be a pedal box issue? 

[nickcoll]

I used to have that same problem with my previous diesel engine. It never happend after i learned to give it a beating now and then. If you drive your diesel enging like you're driving miss Daisy this is a problem that will continue.

 

How does that work, then, with a modern engine? Like, with high pressure injection? And no spark plugs to get fouled?

[Gabbo]

When regen activates there is sometimes a small engine hesitation (bump) as the engine changes combustion modes.

You can check if its regen activating causing this by looking at the vehicle status if you have Amundsen or Columbus.

The StopStart information will go from "StopStart Available" to "Engine Must be Running".

 

The DPF on the Mk3 diesel seems to be quite small so Regen can activate quite often & with short intervals especially if it is interupted while running.

 

If you are taking the car to the dealer you could ask them to check that you have the latest software & calibration for the engine ECU also as these kinds of hesitations & driviability problems are often improved with a new calibration.

[Gabbo]

I used to have that same problem with my previous diesel engine. It never happend after i learned to give it a beating now and then. If you drive your diesel enging like you're driving miss Daisy this is a problem that will continue.

 

 

How does that work, then, with a modern engine? Like, with high pressure injection? And no spark plugs to get fouled?

 

This was a frequent problem on many old Euro3 diesel engines where EGR valves were introduced to meet emissions targets & the control systems were not so precise.

Driving at very low RPM caused poor smokey combustion & when combined with lots of short journeys (where the engine was cold & air moist) could cause sticky soot to build up around the turbo & egr valve which caused them to block/stick.

 

It shouldn't be a problem with more modern engines as the engine control & strategies to prevent this from happening are much improved.

[BjornP]

Aircon compressor kicking in? This is very distinct in my 500 abarth, not felt this so far in the skoda though..

Edited 4 August, 2014 by BjornP

[morty]

mine does the same every now and again on a trailing throttle usually downhill

[1600cr]

It's not unique to the VRS guys. My 1.6 tdi does it, I originally thought it was down to the tuning box but removed it for 2 days and it's still there, I've also test driven a 2.0 150 tdi and that also had the same feeling.

I don't know wether it's some sort of hole in the mapping, an issue with fly by wire throttle or something to do with the brake assist ?

[mangoletse]

Well, I've given it a couple of weeks fatidiously keeping out of 5th gear and the problem has not surfaced in any of the usual points on the route. So I've forgotten about it to an extent, although it now occurs in a different place, by which time I'm not really concentrating on it and can't remember what's going on. However, I'm pretty sure its a case of slowing down and staying in a higher gear - I guess my only analogy would be in an old carburettored petrol car, that massive jerking you'd get. I do find that staying out of 5th is much better for the drive dynamics at lower speeds, in spite of what the maxidot tells me, and in fact I've stopped noticing it at all now.

 

Those taxi drivers who make it into top gear at 10mph, how do they manage it!?

[JBR10]

Mangoletse

 

Check out the other threads titled "Throttle Flat Spot issues" and "TDI VRS - Momentary Loss of Power.  What you seeing is all too familar - it sounds like exactly the same issue to me.

[kallekilponen]

Mangoletse

 

Check out the other threads titled "Throttle Flat Spot issues" and "TDI VRS - Momentary Loss of Power.  What you seeing is all too familar - it sounds like exactly the same issue to me.

Here are the links:

 

http://www.briskoda.net/forums/topic/337285-throttle-flat-spot-issues/

 

http://www.briskoda.net/forums/topic/346206-tdi-vrs-momentary-losses-of-power/