On Tue, 02 Jul 2019 09:39:34 +0100
Scott wrote:

2008 vehicle. The new ones probably have an app for the mobile phone
that carries out a full diagnostic test !!!

The Micra does too if you plug an OBD-II dongle into it.

On Mon, 01 Jul 2019 21:24:03 +0100
Scott wrote:

I am wondering if my clutch is on the way out. The biting point seems
to be getting higher, the engine sometimes speeds up during gear
changes and the car seems less lively on hills. Vehicle has done
nearly 70,000 miles. Does this sound like a clutch issue?

It could be the actuator (cable or hydraulic?) rather than the clutch
itself.

On 02/07/2019 23:52, Fredxx wrote:
On 02/07/2019 21:44, Steve Walker wrote:
On 02/07/2019 12:11, wrote:
On Monday, 1 July 2019 22:45:55 UTC+1, Steve WalkerÂ* wrote:

have had to change the clutch on due to wear was my first car (a Yugo
45) and that had been a driving school car before I had it!

what are Yugos really like?

Well that was in the '80s. Yugos and Ladas (part of my learning was in
a Lada) were basically older Fiat designs or at least based on Fiat
mechanicals.

I'm sorry but I disagree. The Lada, have no idea about Yugos, had the
floorpan and bodyshell of a Fiat 124.

The engine and running gear, brakes and suspension were Russian design.
And as rugged as hell.

I recall an issue with calipers, where a round cylinder was held/pressed
into a carrier. Naturally it would stop being round and the piston seize
in the bore.

They were overhead cam (chain driven), some had Weber carbs. The
thermostat was a sophisticated bypass affair. It was fearfully
uneconomical!

You learn something new every day.

SteveW

On 02/07/2019 21:36, Steve Walker wrote:
It is likely that the driver has missed the brake pedal, caught the
accelerator, but thinks that their foot is on the brake and so presses
harder and everything happens so quickly that there is no time to
correct the error.
My ate motherdive into the back of a stationary artic in the middle of a
town.

"I forgot where the brake pedal was"

She wasnt required to take a test and her dementia had not been
officailly diqagnosed.

She bought another car. And drove for another 2 years.



--
€œit should be clear by now to everyone that activist environmentalism
(or environmental activism) is becoming a general ideology about humans,
about their freedom, about the relationship between the individual and
the state, and about the manipulation of people under the guise of a
'noble' idea. It is not an honest pursuit of 'sustainable development,'
a matter of elementary environmental protection, or a search for
rational mechanisms designed to achieve a healthy environment. Yet
things do occur that make you shake your head and remind yourself that
you live neither in Joseph Stalins Communist era, nor in the Orwellian
utopia of 1984.€�

Vaclav Klaus

On Wed, 3 Jul 2019 00:33:20 +0100, Rob Morley
wrote:

On Tue, 02 Jul 2019 09:39:34 +0100
Scott wrote:

2008 vehicle. The new ones probably have an app for the mobile phone
that carries out a full diagnostic test !!!

The Micra does too if you plug an OBD-II dongle into it.

Actually, I have done that. It never occurred to me that it could
detect a mechanical failure such as a clutch.

"Jethro_uk" wrote in message
...
On Tue, 02 Jul 2019 18:30:18 +0100, Dave Plowman (News) wrote:

In article ,
Andy Burns wrote:
Dave Plowman wrote:

It may make sense to change the clutch sooner rather than later. To
avoid damage to the flywheel.

If it's a diesel, it seems the done thing is to replace the DMF at the
same time ... or get shot of the vehicle.

Quite.

I can remember simply replacing the driven plate in years gone by.
Clutch cover and flywheel still OK. ;-)

It was a false economy job beloved of back-street cowboy workshops.
Especially if the bulk of the cost of the job was the labour to remove
the gearbox.

Some garages would love to charge you all over again for the engine-out
labour to replace the DMF at a later date.

I was impressed with my garage who recommended that I have the water pump
replaced (*) at the same time as the cambelt was being routinely changed, to
avoid me having to pay twice for the labour, given that the water pump is
driven off the cambelt on my car.


(*) Even if it seemed to be working fine. Cost of water pump is much less
than cost of labour to remove it.

"Bill" wrote in message
tairs...
With the first Octavia, I was planning to get the DMF changed to a proper
flywheel (Skoda do one for taxis), but other things went wrong, so I
traded it in. We still have the newer one and at just over 100k miles, the
"feature" is there, but liveable with.

What are the advantages and disadvantages of a dual mass flywheel?
https://en.wikipedia.org/wiki/Dual-mass_flywheel seems to imply that with a
high-torque-at-low-revs engine (a diesel) a DMF is highly desirable to
absorb some of the peaks in the torque as each cylinder fires. Is the
disadvantage mainly that it is more complex and therefore more costly?

"Jethro_uk" wrote in message
...
On Tue, 02 Jul 2019 17:16:16 +0000, Marland wrote:

Many grannies have poor clutch control partly I suppose due to weakening
of leg and foot muscles or painful joints,

Also driving in heels can lead to the sole lightly touching the pedal.
Enough to cause a permanent micro-slip which wears the clutch.

A woman I worked with always lifted her whole foot off the floor as she
released the clutch, rather than keeping her heel on the floor and using it
as a pivot to give greater control of the clutch. And she rarely wore high
heels, so it wasn't a way of compensating for that.

On 03/07/2019 09:57, NY wrote:
"Jethro_uk" wrote in message
...
On Tue, 02 Jul 2019 18:30:18 +0100, Dave Plowman (News) wrote:

In article ,
Â*Â* Andy Burns wrote:
Dave Plowman wrote:

It may make sense to change the clutch sooner rather than later. To
avoid damage to the flywheel.

If it's a diesel, it seems the done thing is to replace the DMF at the
same time ... or get shot of the vehicle.

Quite.

I can remember simply replacing the driven plate in years gone by.
Clutch cover and flywheel still OK. ;-)

It was a false economy job beloved of back-street cowboy workshops.
Especially if the bulk of the cost of the job was the labour to remove
the gearbox.

Some garages would love to charge you all over again for the engine-out
labour to replace the DMF at a later date.

I was impressed with my garage who recommended that I have the water
pump replaced (*) at the same time as the cambelt was being routinely
changed, to avoid me having to pay twice for the labour, given that the
water pump is driven off the cambelt on my car.


(*) Even if it seemed to be working fine. Cost of water pump is much
less than cost of labour to remove it.

I raidse yuou 6 hours of labour to replace a £5 thermostat in a
freelander TD4


--
Any fool can believe in principles - and most of them do!

On 02/07/2019 21:36, Steve Walker wrote:
On 02/07/2019 11:32, NY wrote:
"T i m" wrote in message
...

(*) I wonder if some of these car-crashes-into-supermarket "the car
just took off - I couldn't stop it" incidents are when the engine is
racing at 2000 and the driver lets the clutch in slightly more than
normal (or his clutch foot gets tired) and the car lurches forwards.
Much better to use the lowest engine speed that will still pull
without stalling - less opportunity for error ;-)

In most cases the cars involved seem to be automatic.

It is likely that the driver has missed the brake pedal, caught the
accelerator, but thinks that their foot is on the brake and so presses
harder and everything happens so quickly that there is no time to
correct the error.

I was in a crash caused by that error as a rear seat passenger. The
other driver insisted they pressed the brake as hard as they could but
their speed increased and there were no skid marks (pre ABS brakes).

Police crash investigators concluded they hit the accelerator pedal.

I have declutched the brake on an automatic car more than once - usually
in an unfamiliar hire car when approaching a complicated pay station
chicane in some horrible dingy multistorey carpark.

--
Regards,
Martin Brown

In article ,
Scott wrote:
On Wed, 3 Jul 2019 00:33:20 +0100, Rob Morley
wrote:

On Tue, 02 Jul 2019 09:39:34 +0100
Scott wrote:

2008 vehicle. The new ones probably have an app for the mobile phone
that carries out a full diagnostic test !!!

The Micra does too if you plug an OBD-II dongle into it.

Actually, I have done that. It never occurred to me that it could
detect a mechanical failure such as a clutch.

I doubt it does.

--
*Many hamsters only blink one eye at a time *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman wrote:

Scott wrote:

Rob Morley wrote:

The Micra does too if you plug an OBD-II dongle into it.

Actually, I have done that. It never occurred to me that it could
detect a mechanical failure such as a clutch.

I doubt it does.

Cars with flappy-paddles monitor the pressure and temperature of
multiple valves in the mechatronics unit that operates the clutches.

On 03/07/2019 11:23, Jethro_uk wrote:
On Wed, 03 Jul 2019 10:02:31 +0100, NY wrote:

"Bill" wrote in message
tairs...
With the first Octavia, I was planning to get the DMF changed to a
proper flywheel (Skoda do one for taxis), but other things went wrong,
so I traded it in. We still have the newer one and at just over 100k
miles, the "feature" is there, but liveable with.

What are the advantages and disadvantages of a dual mass flywheel?
https://en.wikipedia.org/wiki/Dual-mass_flywheel seems to imply that
with a high-torque-at-low-revs engine (a diesel) a DMF is highly
desirable to absorb some of the peaks in the torque as each cylinder
fires. Is the disadvantage mainly that it is more complex and therefore
more costly?

I think the idea is it acts like a light weight for when the velocity of
the flywheel needs to change quickly, but a heavy weight when it's needed
to keep the engine stable.

No. It doesn't and thats not the idea.

It acts *like* a heavy flywheel in terms of smoothing out torque pulses
but it is in fact lighter.


There are springs and weights involved which
are slotted into a recess in the flywheel. I'm guessing there are metal
fatigue issues around having to much around with the single casting of
the flywheel.

I wonder if a system with two flywheels might be better ?

It *is* a system with two flywheels


--
The lifetime of any political organisation is about three years before
its been subverted by the people it tried to warn you about.

Anon.

"Martin Brown" wrote in message
...
I was in a crash caused by that error as a rear seat passenger. The other
driver insisted they pressed the brake as hard as they could but their
speed increased and there were no skid marks (pre ABS brakes).

Police crash investigators concluded they hit the accelerator pedal.

What is the typical police response if they suspect that the driver hit the
accelerator instead of the footbrake. Is it regarded as a venial sin ("ah,
what a silly thing to do - try not to do it again") or is it treated as
careless/dangerous driving, maybe with reactions checked in a driving test?
I get the impression that confusing the two controls is regarded as less
serious and more forgivable than driving at 35 in a 30 zone or going through
a red traffic light 2 seconds after it has changed when there's no other
traffic around (I'd regard those latter two as far less serious because they
are technical, potential faults rather than an actual collision-causing
fault).


I have declutched the brake on an automatic car more than once - usually
in an unfamiliar hire car when approaching a complicated pay station
chicane in some horrible dingy multistorey carpark.

Likewise - usually because of my foot, instinctively feeling for the
non-existent clutch, catches that stupid double-width brake pedal that all
automatic cars are fitted with for some godforsaken reason. I *never* brake
with my left foot in an automatic: a) because I never want to brake and
accelerate at the same time, so the same right foot will do for both, as in
a manual, and b) because my left foot is attuned to larger, often less
precise movements of the clutch pedal, so I wouldn't instinctively have the
fine control to apply the brake without pressing too hard (*knowing* is one
thing, reflex action in an emergency is quite another). If I have to do a
hill start in an automatic, I don't use my left foot as I am pressing the
accelerator with my right foot - I use my handbrake, as in a manual. And I
almost always (*) go into neutral and apply the handbrake at traffic lights,
as in a manual, to avoid me having to keep my foot on the brake - something
I would regard as a hanging offence (!) because it dazzles the driver(s)
behind at night.

I remember when I went go-karting, where the brake is operated with the left
foot, we were all warned at the end of our session that if we'd driven
there, we needed to pay particular attention to braking with the right foot
again as we drove home.

I often find that when I drive a strange car, I get used to the different
feel and location of its controls fairly quickly, but I then take a lot
longer to get used to my own car again that I am much more familiar with.
You'd think it would be the other way round. Trying to remember where
reverse is can be a hassle: top-left (left of first) on my Peugeot,
bottom-right (right of sixth) on my wife's Honda: and yet it's always my
Peugeot, which I drive a lot more, that I have to think about - weird.


(*) Except when I anticipate that I'll only be stopped for a few seconds, as
for a manual. I don't go into Park because that flashes the reversing lights
as you move from Drive through Reverse to Park and back, which scares the
living daylights out of the car behind...

On 03/07/2019 11:40, NY wrote:
Likewise - usually because of my foot, instinctively feeling for the
non-existent clutch, catches that stupid double-width brake pedal that
all automatic cars are fitted with for some godforsaken reason. I
*never* brake with my left foot in an automatic: a) because I never want
to brake and accelerate at the same time, so the same right foot will do
for both, as in a manual, and b) because my left foot is attuned to
larger, often less precise movements of the clutch pedal, so I wouldn't
instinctively have the fine control to apply the brake without pressing
too hard (*knowing* is one thing, reflex action in an emergency is quite
another).

I ALWAYS brake with my left foot on an automatic because there are
really sound and very very practical resons to use the brake and
accelerator at the same time.

1/. When wanting to pull away smartly, mediuem revs and foot on brake
allwos realse of brake like a cluch to get the vehicle smartly off the mark.
2/. When wanting to force a kckdown mid corner, use brake and
accelerator then release the brake to accelerate out of the corner.

3/. When parking especially on a slope, so that you don't control a car
that is effectively in gear all the time, on the accelator and then have
to switch to the brake to stop it demolishing the garage. Friend of mine
did that.

The problem I have is then missing the brake on a manual and depressing
the clutch. Takes me about 5 minutes to get back into manual mode,

If I have to do a hill start in an automatic, I don't use my
left foot as I am pressing the accelerator with my right foot - I use my
handbrake, as in a manual.

Umm. You shouldnt need to use a barke at all in an auto to do a hill strat.

And I almost always (*) go into neutral and
apply the handbrake at traffic lights, as in a manual, to avoid me
having to keep my foot on the brake - something I would regard as a
hanging offence (!) because it dazzles the driver(s) behind at night.

I put the ****er in 'park'.


--
There is nothing a fleet of dispatchable nuclear power plants cannot do
that cannot be done worse and more expensively and with higher carbon
emissions and more adverse environmental impact by adding intermittent
renewable energy.

In message , Jethro_uk
writes
On Wed, 03 Jul 2019 10:02:31 +0100, NY wrote:

"Bill" wrote in message
tairs...
With the first Octavia, I was planning to get the DMF changed to a
proper flywheel (Skoda do one for taxis), but other things went wrong,
so I traded it in. We still have the newer one and at just over 100k
miles, the "feature" is there, but liveable with.

What are the advantages and disadvantages of a dual mass flywheel?
https://en.wikipedia.org/wiki/Dual-mass_flywheel seems to imply that
with a high-torque-at-low-revs engine (a diesel) a DMF is highly
desirable to absorb some of the peaks in the torque as each cylinder
fires. Is the disadvantage mainly that it is more complex and therefore
more costly?

I think the idea is it acts like a light weight for when the velocity of
the flywheel needs to change quickly, but a heavy weight when it's needed
to keep the engine stable. There are springs and weights involved which
are slotted into a recess in the flywheel. I'm guessing there are metal
fatigue issues around having to much around with the single casting of
the flywheel.

I wonder if a system with two flywheels might be better ?

I sometimes look at the "Briskoda" Skoda forum, where the general view
seemed to be that the SMF was far superior to the DMF on the diesel
Octavia.
OTOH, I discussed it with the local (usually excellent) agent, who said
they had fitted a couple of SMF's to taxis, and they had both returned
and reverted to DMF's.

The forum advocates of SMF's mostly appeared to have used the same
manufacturer for their non-OEM flywheels. My guess was that these
flywheels were heavier than the others.

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.

I like boat diesels with really heavy flywheels. I suspect the lighter
mass of the DMF makes for a much more lively engine in a car.

--
Bill

On 03/07/2019 11:50, Bill wrote:
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.

Sounds like not enough revs and a too-light flywheel.
DMF is probably a good idea - like IRS - if done properly. I.e. not
swinging rear axles...I suspect the springs masses and damping need
careful tuning and more development that they have in fact had...


--
"In our post-modern world, climate science is not powerful because it is
true: it is true because it is powerful."

Lucas Bergkamp

"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.

In article ,
Andy Burns wrote:
Dave Plowman wrote:

Scott wrote:

Rob Morley wrote:

The Micra does too if you plug an OBD-II dongle into it.

Actually, I have done that. It never occurred to me that it could
detect a mechanical failure such as a clutch.

I doubt it does.

Cars with flappy-paddles monitor the pressure and temperature of
multiple valves in the mechatronics unit that operates the clutches.

Which type of box with flappy paddles? Some conventional torque converter
auto boxes have those.

But the synchromesh type have multi plate wet clutches, hydraulically
operated. More chance of getting a reading of sorts from that than a
typical clutch. As in a Micra.

--
*Frankly, scallop, I don't give a clam

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
NY wrote:
Likewise - usually because of my foot, instinctively feeling for the
non-existent clutch, catches that stupid double-width brake pedal that
all automatic cars are fitted with for some godforsaken reason. I
*never* brake with my left foot in an automatic: a) because I never
want to brake and accelerate at the same time, so the same right foot
will do for both, as in a manual, and b) because my left foot is
attuned to larger, often less precise movements of the clutch pedal, so
I wouldn't instinctively have the fine control to apply the brake
without pressing too hard

I always left foot brake on an auto. Why have two pedals and two feet but
only use one?

It does take some getting used to at first - but then becomes second
nature. And I don't have a problem driving a manual either.

It might be tricky if you had two identical cars, one manual, one auto.
But different cars have different controls anyway. So no different from
remembering where the light switch is.

--
*WHERE DO FOREST RANGERS GO TO "GET AWAY FROM IT ALL?"

Dave Plowman London SW
To e-mail, change noise into sound.

In article s,
Bill wrote:
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.

On most cars if you try to move off very fast with a lot of steering lock,
it will tend to spin a wheel. Could it be some form of traction control
cutting in?

--
*We have enough youth, how about a fountain of Smart?

Dave Plowman London SW
To e-mail, change noise into sound.

On 03/07/2019 11:40, NY wrote:
"Martin Brown" wrote in message
...
I was in a crash caused by that error as a rear seat passenger. The
other driver insisted they pressed the brake as hard as they could but
their speed increased and there were no skid marks (pre ABS brakes).

Police crash investigators concluded they hit the accelerator pedal.

What is the typical police response if they suspect that the driver hit
the accelerator instead of the footbrake. Is it regarded as a venial sin
("ah, what a silly thing to do - try not to do it again") or is it

Pretty much.

treated as careless/dangerous driving, maybe with reactions checked in a
driving test? I get the impression that confusing the two controls is
regarded as less serious and more forgivable than driving at 35 in a 30
zone or going through a red traffic light 2 seconds after it has changed
when there's no other traffic around (I'd regard those latter two as far
less serious because they are technical, potential faults rather than an
actual collision-causing fault).

There was no prosecution although the road layout was improved
afterwards by moving hedges back so that the sight line at the junction
allowed you to better see the car that would be likely to hit you.



Originally the hedge was a yard from the kerb everywhere and there was a
very solid stone gate post just opposite where we came to rest.

My honest opinion is that both drivers made a mistake. The last thing I
can recall thinking before I passed out was "it's going to be close".

I have declutched the brake on an automatic car more than once -
usually in an unfamiliar hire car when approaching a complicated pay
station chicane in some horrible dingy multistorey carpark.

Likewise - usually because of my foot, instinctively feeling for the
non-existent clutch, catches that stupid double-width brake pedal that
all automatic cars are fitted with for some godforsaken reason.

It is a classic error when using an automatic car when used to a manual.
Basically in moments of stress it is all to easy to declutch the brake.

--
Regards,
Martin Brown

In message , The Natural Philosopher
writes
On 03/07/2019 11:50, Bill wrote:
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
a bang and the engine stops dead. I wonder if there is some damping on
the springs which can fail.

Sounds like not enough revs and a too-light flywheel.
DMF is probably a good idea - like IRS - if done properly. I.e. not
swinging rear axles...I suspect the springs masses and damping need
careful tuning and more development that they have in fact had...

The point is that the judder and the bang and stalled engine only happen
on trips where I have been involved in long, multi-stationary crawling
traffic.

I haven't done any tests with over-revving the engine before engaging
the clutch, but I think it used to happen with the older car with
different revs. My impression was that as the clutch engaged fairly
sharply, the engine revs dropped to a point where a resonance caused
conflicting forces at the engine/clutch interface, hence the bang.

The fact that the newer car shows similar, but much less significant
symptoms, might indicate that some development had occurred between 2007
and 2010.
--
Bill

In message , NY writes
"Bill" wrote in message
. stairs...
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.

It is on a Skoda, and, yes, I think the 1.9tdi is a PD engine (although
I could be wrong). However, I haven't noticed those effects. Maybe your
test drive vehicle had the start of the effect I'm describing.
--
Bill

Bill wrote:
In message , NY writes
"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.

It is on a Skoda, and, yes, I think the 1.9tdi is a PD engine (although
I could be wrong). However, I haven't noticed those effects. Maybe your
test drive vehicle had the start of the effect I'm describing.

No, its the engine management just killing the engine if the revs drop too
low. I suspect very low revs can induce damaging resonances in dual mass
flywheels. Ive experienced it in many modern diesels.

Tim

--
Please don't feed the trolls

"Tim+" wrote in message
...
No, its the engine management just killing the engine if the revs drop
too
low. I suspect very low revs can induce damaging resonances in dual mass
flywheels. Ive experienced it in many modern diesels.

I've not experienced engine-killing on any other diesel engine than the VW
PD engine: Peugeot 1.9 XUD, 2.0 HDi, 1.6 HDi, Honda 1.7 (in 2002 Civic),
Honda 1.6 (in CR-V), and various others - none of these suffer the engine
dying if the revs drop below a certain level due to insufficient fuel or too
much mechanical load. which causes a very sudden stop within a fraction of a
second as if the ignition had been turned off.

The 1.6 in the CR-V seems to run short of turbo pressure if the engine revs
drop too low for the mechanical load: I find I need to be in at least one
gear, maybe two gears, lower than in my Pug 308 (1.6 HDi) when accelerating
out of roundabouts and T junctions, or when going up hills - and once the
engine fails to pull, it needs a much lower gear than it would normally do
in that situation to get it to pull again - maybe the engine needs to rev
faster than normal to produce enough exhaust to spin the turbo to generate
more inlet pressure. Normally I think "I'd take this roundabout in third in
Pug, so I need 2nd in the Honda" but occasionally I forget and it bites me
in the bum and I have to try to change down *smoothly* right when I want to
accelerate, without overcooking it and surging forward.

On 03/07/2019 10:55, Martin Brown wrote:
On 02/07/2019 21:36, Steve Walker wrote:
On 02/07/2019 11:32, NY wrote:
"T i m" wrote in message
...

(*) I wonder if some of these car-crashes-into-supermarket "the car
just took off - I couldn't stop it" incidents are when the engine is
racing at 2000 and the driver lets the clutch in slightly more than
normal (or his clutch foot gets tired) and the car lurches forwards.
Much better to use the lowest engine speed that will still pull
without stalling - less opportunity for error ;-)

In most cases the cars involved seem to be automatic.

It is likely that the driver has missed the brake pedal, caught the
accelerator, but thinks that their foot is on the brake and so presses
harder and everything happens so quickly that there is no time to
correct the error.

I was in a crash caused by that error as a rear seat passenger. The
other driver insisted they pressed the brake as hard as they could but
their speed increased and there were no skid marks (pre ABS brakes).

Police crash investigators concluded they hit the accelerator pedal.

I have declutched the brake on an automatic car more than once - usually
in an unfamiliar hire car when approaching a complicated pay station
chicane in some horrible dingy multistorey carpark.


You don't half stop quick when you do that! I've only done it the once,
having driven an automatic for the first time, setting off from
Manchester and driving to Bury St. Edmunds - spotted the company I was
heading for and forgot it was an automatic.

No trouble after that, but I have very rarely driven an automatic since
- that was just the only pool car that day.

SteveW

On 03/07/2019 08:04, Jethro_uk wrote:
On Tue, 02 Jul 2019 23:52:19 +0100, Fredxx wrote:

On 02/07/2019 21:44, Steve Walker wrote:
On 02/07/2019 12:11, wrote:
On Monday, 1 July 2019 22:45:55 UTC+1, Steve WalkerÂ* wrote:

have had to change the clutch on due to wear was my first car (a Yugo
45) and that had been a driving school car before I had it!

what are Yugos really like?

Well that was in the '80s. Yugos and Ladas (part of my learning was in
a Lada) were basically older Fiat designs or at least based on Fiat
mechanicals.

I'm sorry but I disagree. The Lada, have no idea about Yugos, had the
floorpan and bodyshell of a Fiat 124.

The engine and running gear, brakes and suspension were Russian design.
And as rugged as hell.

I recall an issue with calipers, where a round cylinder was held/pressed
into a carrier. Naturally it would stop being round and the piston seize
in the bore.

They were overhead cam (chain driven), some had Weber carbs. The
thermostat was a sophisticated bypass affair. It was fearfully
uneconomical!

Not a cable in sight, either.

The accelerator was via a cable, can't recall the clutch.

It had a new fangled alternator, except it had a mechanical reed
regulator that I changed to a 2n3055 + zener affair. The old regulator
would stick and the lights go all bright for a second or so!

NY wrote
Martin Brown wrote

I was in a crash caused by that error as a rear seat passenger. The other
driver insisted they pressed the brake as hard as they could but their
speed increased and there were no skid marks (pre ABS brakes).

Police crash investigators concluded they hit the accelerator pedal.

What is the typical police response if they suspect that the driver hit
the accelerator instead of the footbrake. Is it regarded as a venial sin
("ah, what a silly thing to do - try not to do it again") or is it treated
as careless/dangerous driving, maybe with reactions checked in a driving
test?

They dont normally get involved unless someone
is injured or you get some spectacular result like
driving right out the side of a multi story carpark etc.

I get the impression that confusing the two controls is regarded as less
serious and more forgivable than driving at 35 in a 30 zone or going
through a red traffic light 2 seconds after it has changed when there's no
other traffic around (I'd regard those latter two as far less serious
because they are technical, potential faults rather than an actual
collision-causing fault).

I have declutched the brake on an automatic car more than once - usually
in an unfamiliar hire car when approaching a complicated pay station
chicane in some horrible dingy multistorey carpark.

I do it quite a bit now, mostly when parking. I didnt used
to when I used work cars, mine were always manual and
still are tho that may well change if I can find a car with
a decent fully automatic cruise control.

Not clear what that changed. I certainly used to use work
automatics much more than I drive automatics now.

Likewise - usually because of my foot, instinctively feeling for the
non-existent clutch, catches that stupid double-width brake pedal that all
automatic cars are fitted with for some godforsaken reason.

Dont remember ever having had that problem.

I *never* brake with my left foot in an automatic: a) because I never want
to brake and accelerate at the same time, so the same right foot will do
for both, as in a manual, and b) because my left foot is attuned to
larger, often less precise movements of the clutch pedal, so I wouldn't
instinctively have the fine control to apply the brake without pressing
too hard (*knowing* is one thing, reflex action in an emergency is quite
another). If I have to do a hill start in an automatic, I don't use my
left foot as I am pressing the accelerator with my right foot - I use my
handbrake, as in a manual.

I dont.

And I almost always (*) go into neutral and apply the handbrake at traffic
lights, as in a manual, to avoid me having to keep my foot on the brake -

I dont.

something I would regard as a hanging offence (!) because it dazzles the
driver(s) behind at night.

I've never been dazzled in that situation myself.

I remember when I went go-karting, where the brake is operated with the
left foot, we were all warned at the end of our session that if we'd
driven there, we needed to pay particular attention to braking with the
right foot again as we drove home.

I often find that when I drive a strange car, I get used to the different
feel and location of its controls fairly quickly, but I then take a lot
longer to get used to my own car again that I am much more familiar with.

I dont get that effect either. My own car feels very natural when I
drive it again and I usually do drive my car to where the borrowed
automatic is and then get back into my own car immediately after
returning the automatic. Now I mostly drive other people's automatic
when I am driving them to an adjacent major town for a medical
appointment and so use their car for that trip.

You'd think it would be the other way round.

Yeah, thats the result I get.

Trying to remember where reverse is can be a hassle: top-left (left of
first) on my Peugeot, bottom-right (right of sixth) on my wife's Honda:
and yet it's always my Peugeot, which I drive a lot more, that I have to
think about - weird.

(*) Except when I anticipate that I'll only be stopped for a few seconds,
as for a manual. I don't go into Park because that flashes the reversing
lights as you move from Drive through Reverse to Park and back, which
scares the living daylights out of the car behind...

Dave Plowman wrote:

Andy Burns wrote:

Cars with flappy-paddles monitor the pressure and temperature of
multiple valves in the mechatronics unit that operates the clutches.

Which type of box with flappy paddles?

DSG

But the synchromesh type have multi plate wet clutches, hydraulically
operated.

aka mechatronics, but I should have said it operates the gear changes as
well as the clutches.

On Thu, 4 Jul 2019 04:37:37 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


What is the typical police response if they suspect that the driver hit
the accelerator instead of the footbrake. Is it regarded as a venial sin
("ah, what a silly thing to do - try not to do it again") or is it treated
as careless/dangerous driving, maybe with reactions checked in a driving
test?

They don¢t normally get involved unless

I doubt his questions were meant for you, you self-important senile asshole
from Oz! BG

--
Bill Wright to Rot Speed:
"That confirms my opinion that you are a despicable little ****."
MID:

Jethro_uk wrote:

Weren't there some public transport systems which used flywheels on the
trains instead of engines and had the engines in stations ? Until a
flywheel came loose ....

http://www.parrypeoplemovers.com/

Chris
--
Chris J Dixon Nottingham UK
@ChrisJDixon1

Plant amazing Acers.

In article ,
Andy Burns wrote:
Dave Plowman wrote:

Andy Burns wrote:

Cars with flappy-paddles monitor the pressure and temperature of
multiple valves in the mechatronics unit that operates the clutches.

Which type of box with flappy paddles?

DSG

So the early type with a single clutch? Later ones have twin layshafts and
clutches so you get no interruption of power on a gearshift between
sequential gears. And are rather more gentle on those clutches. Nothing
from that appears on OBD on mine. I'm told the clutches should have the
same life as the gearbox.

But the synchromesh type have multi plate wet clutches, hydraulically
operated.

aka mechatronics, but I should have said it operates the gear changes as
well as the clutches.

Indeed.

The first SMG type box I tried was pretty crude. Nothing like as smooth as
a conventional auto under normal use. Although certainly not bad when in a
hurry. The later twin layshaft type pretty well as smooth as a torque
convertor auto in normal use, but without the transmission losses, and
changes gear even faster than the SMG. The only downside is the auto
clutch ain't quite as controllable as a torque convertor when creeping -
like when parking. But a small price to pay.

--
*The sooner you fall behind, the more time you'll have to catch up *

Dave Plowman London SW
To e-mail, change noise into sound.

Chris J Dixon wrote:
Jethro_uk wrote:

Weren't there some public transport systems which used flywheels on the
trains instead of engines and had the engines in stations ? Until a
flywheel came loose ....

http://www.parrypeoplemovers.com/

Chris

An earlier implementation of the flywheel concept were a couple of bus
routes
https://en.m.wikipedia.org/wiki/Gyrobus

Surprising in a place where you would think anything abandoned would be
recycled fairly quickly one of the charging points of the system introduced
when the Town was Leopoldville in the Belgian Congo
was still in place till recently and may still be.

https://images.app.goo.gl/8CzWYtuKeNm1qJ64A

GH

Dave Plowman wrote:

Andy Burns wrote:

Dave Plowman wrote:

Which type of box with flappy paddles?

DSG

So the early type with a single clutch?

no, I did say clutches

Later ones have twin layshafts and
clutches so you get no interruption of power on a gearshift between
sequential gears. And are rather more gentle on those clutches. Nothing
from that appears on OBD on mine. I'm told the clutches should have the
same life as the gearbox.

Mine got a bit lumpier after 4 years, would occasionally throw up a
transmission fault code when going over a deep pothole, and I was
worried enough about it after 7 that I'd looked at getting it replaced
(there is a local DSG specialist) but then I plumped for chopping it in
instead ... on the final journey up from Leicester to Grange-over-Sands
the DSG overheated and I had to reset the faults with an OBD cable
before getting to the dealer ...