Has anyone noticed a part throttle hesitation with the 2.0l tdi engine. When I rev it to about 2.5k and ease off on the throttle, then open it up again it hesitates before accelerating. I'm new to Diesel but I

Turbo-lag? Isn't 2.5K around where it gets going?

The engine spec figures show that max torque (320Nm) is between 1750 and 2500 rpm.

Yep

Noticed it on mine.

Changing down from 6th to 5t and 5th to 4th the engine seems to falter.

Not a big problem but going to mention it at the first service to see if it can be sorted.

The engine doesn't seem as torquey to me in 5th and 6th as my old Passat 1.9 Sport with I assume similar 6 speed box.

Forever changing down for hills aand overtaking whereas the Passat seemed to take it OK in 6th

I've noticed that if you have to change down from 6th to 5th gear, it makes no difference until I put in 4th on slow uphills behind lorrries!!!

I have booked it in with the dealer next week so will let you folks know what, if anything, is the outcome. I have only noticed it in 5th and 6th at motorway speeds.

Add me to the list; I had the MAF changed under warranty already; seemed to help but still does it. I wonder if in the interests of economy the fuel is cut if you take your foot off?

But I disagree about the pull in 5/6th, its pulls very strongly in both above 2000 rpm.

...ease off on the throttle, then open it up again it hesitates before accelerating.

This is turbo lag. Many people get this confused with the boost threshold rpm where the turbo starts working. Modern turbo charged petrol and diesel engines have minimized this to an almost negligible level, but it is still there, and the more you drive your car, the more you will notice it. This is why you will hear motoring journalists talking about the instance throttle response of a normally aspirated engine.

More info...

http://www.turbochargedpower.com/Common%20Terms.htm

More info...

http://www.turbochargedpower.com/Common%20Terms.htm

I have read with interest the details held on the attached link, and wonder if it is comman practice to allow the turbo time to cool down at the end of a journey. Would this only be required only if driving hard, with lots of boost, or is it good practice that should be adopted for everyday driving?? :confused:

I have read with interest the details held on the attached link, and wonder if it is comman practice to allow the turbo time to cool down at the end of a journey. Would this only be required only if driving hard, with lots of boost, or is it good practice that should be adopted for everyday driving?? :confused:

I do let the turbo cool down on both our cars (Seat Leon Cupra petrol & Skoda Octavia 2.0TDi). This is made easier by the fact that almost every journey I do has a 30/40 mph limit at the end for about the last mile (which at 30mph is the recommended 2 minutes).

The time I get most worried about this is if I've been driving fast on country roads and pull in for petrol/snacks. This is one of those occasions where you hope there is a queue for the pump . On motorways/dual carriageways, it's not really a problem because both our cars will sit at 70mph with very little throttle, and hence very little turbo boost.

I dont think this is turbo lag.

Ive had turbo cars (diesel and petrol) for the past 13 years and havent experienced this before.

Certainly the old Passat 130 Sport and our Fabia Vrs have no trace of this and the 2.0Tdi is supposed be a better engine.

I agree the 2.oTdi pulls very strongly above 2000rpm but in 6th this equates to roughly 70mph. I dont expect to be having to change down at speeds of 55/60 to overtake safely. Seems to me that the latest more powerful diesels have petrol like characteristics. Mates new BMW 3 series is just the same, doesnt pull as well as his old one at lower revs.

I agree: modern diese cars are definitely more "petrol-like" in their characteristics. Hired a Seat Ibiza FR over the weekend: this has the 1.9 VAG diesel, but revs very freely across the range with no appreciable turbo-lag. Certainly, the turbo-charger cuts in much earlier than on my 2.0 TDi. Still, as long as you know when or where it comes, you should be prepared for it: as an afterthought, will remapping help with this issue?????

My Octy II 2.0 PD TDi Elegance does the same thing... only noticed a few times. I would say that it definitely is not turbo lag. More like a slight hiccup, or pause is what I would call it.

Let us all know if anyone gets to the bottom of it, my old A4 1.9 TDi didn't ever have the same kind of issue.

Cheers

A.

My Octy II 2.0 PD TDi Elegance does the same thing... only noticed a few times. I would say that it definitely is not turbo lag. More like a slight hiccup, or pause is what I would call it.

A slight pause is turbo lag. If you drive along at about 2.5K rpm with your foot off the throttle, and then stamp your foot on the throttle, there will be a slight delay before you get any power.

This document (http://tdiclub.com/TDIFAQ/TDiFAQ-1.html#g)

states it as being about 0.25 second for the 1.9 TDi which is why you don't normally notice it. It is only during a quick change from no-throttle to full-throttle that it is noticable.

Can someone describe how this hesitation is different from turbo lag? Does the engine appear to misfire? Do you get turbo lag, a bit of power, then this hesitation?

I'm only asking because I haven't used full throttle yet as the car is still being run in.

The pause on mine is more like the engine missing a few beats. Once or twice it almost felt as if the engine had stalled.

Definitely doesnt feel like turbo lag where you simply dont get any proper power.

Agreed , if is was a petrol engine I'd say it was a misfire when under load

There is a dip in the standard power curve, cannot remember the RPM as the dyno charts are on the PC's at the unit! but there is one

I haven't noticed a flat spot yet after 12k miles but there is an hesitation ; I agree with other posts; I've not noticed on other Tdi s I've driven. :confused:

Here is a standard dyno chart

http://www.briskoda.net/forums/attachment.php?attachmentid=5440&stc=1

Here is a one with Phase One Custom Code

http://www.briskoda.net/forums/attachment.php?attachmentid=5441&stc=1

CUSTOM CODE EDC16 140 MODD.pdf

Definitely not turbo lag, and it is much more noticeable when the engine is warming up. It feels as though the ECU cuts the engine before poking it with a stick, which has the feeling of switching of acceleration before switching it back on. I'd have a guess at a sticking valve of faulty MAF. The car goes in on Friday so will let you all know what the dealer says.

Just to add, my understanding of turbo lag is the time taken to spin up from below the usable rpm, i.e. it doesn't happen at 2.5 to 3k rpm where the turbo will already be spinning and the engine is at 3/4 maximum revs.

Garv the standard plot link doesn't work.

Everyone else with this hesitation. Can you tell me if you lift off the throttle 100% before applying the throttle again?

I only as ask the most annoying thing about the 20TDi to me is the first entry on the throttle table is too high.

i.e. if at idle (800rpm), try to apply the throttle to get 900 or 1000 rpm, can't be done, it's straight to 1100 or more because the first position on the electronic throttle i too high. I'm assuming this is by design and not a fault on mine (would appreciate feedback).

Just wondered if the hesitation you feel is actually the jerk caused by the jump in throttle opening.

Si

The car went back to the dealer yesterday for a check and they found no fault codes or problems. Interestingly after I got the car back it has felt fine, so it could have been a throttle calibration issue.

This may sound stupid.... but could it perhaps be traction control disengaging the engine from drive then slowly letting it back on again to prevent slip etc etc (all mentioned in handbook).

At 60mph on a dry motorway in 5th gear I suspect not.