"Bill" wrote in message
tairs...
Where I suspected a resonant frequency of the DMF flywheel masses and
springs, the effect was - for example - when waiting to turn right across
traffic, a gap appears and you let the clutch in sharply, there is a bang
and the engine stops dead. I wonder if there is some damping on the
springs which can fail.

Is that on a Skoda? I wonder if you've fallen foul of the quirk of some
Volkswagen engines (I presume Skoda and Seat use VW engines) - I think it
was the Mark 5 Golf which used the PD (Pumpe Duse) diesel engine rather than
a more modern HDi-type engine. That model of Golf is the only diesel that I
have ever stalled on test drives - sometimes repeatedly - when setting off.
Even when I drive a petrol car (being used to driving diesels) I don't
stall. But that VW seems to have an ECU which senses that you haven't
applied enough power and instead of chugging, which is warning to apply more
power, and eventually picking up speed, ie normal diesel behaviour, it
reacts by cutting the fuel altogether, making absolutely certain that you
will stall. It is also the only diesel car I've driven that doesn't like
being driven in dense stop-start traffic by lifting the clutch with no
accelerator, controlling the speed by a quick half-blip of clutch (maybe not
even full engagement) and then press the clutch again to coast to a halt a
few yards further on. You have to drive it more like a petrol, with fast
idle and more clutch slippage to avoid going too fast for that engine
speed - not a problem when setting off from rest to accelerate away, but a
problem if you want to move a short distance in a queue of traffic.