surging when accelerating

[Martin Bate]

I'm new to this forum game but hope someone out there can help.

I have a 2007 2.0 Tdi which increases speed in surges when accelerating steadily (not harshly at all). It is as if I am momentarily taking my foot off the accelerator peddle and then putting it straight back on again. Seems to be most noticeable between 1500 and 2500 revs.

All shows as OK on the dash - there are no warning lights or messages.

An initial diagnostic check has not shown up anything.

Speed does increase and it is not that it goes into limp mode (which I had on another 1.9 TDi model).

Any ideas on what might be wrong?

[mscnoe]

Dear Martin - aleluya - at last somebody else with the same problem - I also have the 2007 TDi 140 and it does exactly that. Had it from 4000 miles ex demonstrator (60,000 now and out of warranty) - at every service I raised it with the dealer again and all I can say is that its linked to the clutch pedal which has a switch for the cruise control and apparently to reduce torque when you press the clutch in.

If you very carefully lift your left foot right off the clutch pedal between gear changes it will stop happening - but I still forget, and its most notoceable when loaded to the gunnels on holiday where you use more right foot and spend longer between changes. I was told that Seat have never issued any new engne management firmware to fix this, have considered going for a chip job just to get rid of it - but why do that when performance is ok otherwise. Its annoying but seems to be there and I can't understand why more people don't suffer from it - this engine is used in all sorts of cars, except presumably the performance mapping is different.

Anybody else out there with 2007 2.0 TDi 140 Alhambra - do earlier or later versions still do it, or other tuning levels?

[Martin Bate]

Hi Stuart

Thanks for the suggestion - I'll try it out and report back. Strange that there are not more "sufferes" out there - does this ring a bell with anyone?

I bought mine only relatively recently at this didnt show up on my test drive - fairly sedate listening for noises etc - It has done 29000 miles so far and seems genuine when looking at dealer service records and bills - and I spoke with previous owner - though they had no recollection of this as a problem.

Happy "foruming" and go easy on that left foot.

regards

Martin

[mscnoe]

Hi Martin
I suspect that driving style has a lot to do with this - if I play gently and change up early etc then it is not noticeable. As I mentioned mine was an ex demonstrator and had been run by the head honcho at the garage who denied ever noticing this... over 4,500 miles from new... and like you I never noticed it when taking the car for a test drive!

There is an associated (I think) problem that inflicts itself very occasionally which is potentially more serious/ dangerous - in 55,500 miles it has maybe happened a dozen times and it is this. When decelerating using engine braking or manouvering at low speed the engine will occasionally cut out - I say cut out not stall as it dies - you cannot bump start with the vehicles momentum but have to switch the ignition off and back on whereupon it springs back into life again. It did it once when coming off the M1 onto the M69 southbound - had dropped into 5th, right foot off completely, dropping to maybe 40 - 45 mph - went to change down again as traffic was slowing and on dipping the clutch - engine stopped. Again at bottom of A34 (I think) slowing for large roundabout - same thing maybe in third gear, definately not stalled as vehicle still moving, its got to be linked with that blooming clutch switch. Also reported many times to no avail - because nothing is recorded by the engine management and it can't be made to happen repeatedly there is no chance of ever proving it!
So, next time you think "How did I manage to stall" - it might not be you!

[Martin Bate]

Well - bit of a long trial I know but I tried the "lift fully off the clutch peddle" routine and it works every time. No surging now. Thanks.

I have spotted though that very occasionally the clutch peddle does not always come all the way up when I take my foot off ot. It remains about a half inch below where it should be - when this occurs the surging charachteristic manifests supporting the interfering with the switch as noted on earlier messages. Nudging the peddle up to the top with left foot does the trick. I have not yet investigated why the peddle should not fully return as yet but will peep an eye on it.

Fortinately Ive not had any of the cutting out experiences as yet in 3500 miles since purchase.

Happy days