Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.

Thanks!

Nick

On Thu, 12 Dec 2013 01:17:54 +0000, Nick Odell
wrote:

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.

Doubt it. The engine will just keep going and if the cat's not working
(or not there) it really makes no difference to the engine. This
depends, of course, on that dash light only meaning the cat has
failed, and not something else in control of mixture.

On Thursday, December 12, 2013 1:17:54 AM UTC, Nick Odell wrote:

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter?

Think about it, the cat's output all goes out into the air. It just means more emissions.


NT

Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.



Personally I would have the error code diagnosed as it might be just a case
of a failed/dis-connected sensor or something like that

On 12/12/2013 05:24, Nthkentman wrote:
Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.



Personally I would have the error code diagnosed as it might be just a
case of a failed/dis-connected sensor or something like that

Or someone has nicked his catalytic converter. There has been a spate of
it around Middlebrough recently.

--
Regards,
Martin Brown

On Thu, 12 Dec 2013 07:45:44 +0000, Martin Brown wrote:

Or someone has nicked his catalytic converter. There has been a spate of
it around Middlebrough recently.

Aye, though I suspect the OP might notice a small increase in exhaust
noise as I doubt any tea leaves would join the down pipe back to the
rest of the exhuast system when knicking the cat...

Could just be a knackered/disconnected/dirty conections sensor.

--
Cheers
Dave.

On Thu, 12 Dec 2013 01:17:54 +0000, Nick Odell wrote:

Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done by
driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of months.

Is he sure it's the cat that's failed? Has he read the fault codes?

Unless it's very very recent, not that many cars have post-cat lambdas,
which are really about the only thing that'll infallibly tell the ECU and
fault codes that the cat has failed.

If it IS the cat, and there's no post-cat lambda, then a failed cat is
unlikely to tell the ECU to slap a light up. It'll probably be fine, but
it MAY clog or break up and block the exhaust flow, reducing power
drastically and overheating the exhaust. A fire might result.

If it is the cat, and there's a post-cat lambda, then the ECU might put
the car into a limp-home mode.

If it isn't the cat, then all bets are off. It might run very rich,
drinking fuel and diluting oil. It might be the first warning of another
issue.

If he's guessing it's "just" the cat, he's probably wrong.

Will he be leaving other problems - brakes, f'rinstance - until the MOT,
under this widespread belief that the MOT is all the maintenance a car
needs?

In article , Nthkentman
writes
Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.



Personally I would have the error code diagnosed as it might be just a case
of a failed/dis-connected sensor or something like that

While it may fail a roadside emissions test, the existing MOT is still
valid and the vehicle is unlikely to be unroadworthy.

My only concern would be that failure of the lambda sensor could result
in over rich running and excess hydrocarbons in the exhaust, leading to
damage to the (expensive) CAT. I doubt very much that the light
indicates a failure of the CAT itself or that it is monitored in any
way.

A post to uk.rec.cars.maintenance may be useful too.
--
fred
it's a ba-na-na . . . .

On Wed, 11 Dec 2013 20:19:17 -0800 (PST), wrote:

On Thursday, December 12, 2013 1:17:54 AM UTC, Nick Odell wrote:

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter?

Think about it, the cat's output all goes out into the air. It just means more emissions.


This was my thinking but there are other, different, well-thought-out
opinions in this thread that I'm taking seriously too.

Nick

On Thu, 12 Dec 2013 05:24:46 -0000, "Nthkentman"
wrote:

Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.



Personally I would have the error code diagnosed as it might be just a case
of a failed/dis-connected sensor or something like that

The error code is deffo for the emission control but the duff sensor
is worth looking into.

Nick

On Thu, 12 Dec 2013 09:39:50 +0000, fred wrote:

While it may fail a roadside emissions test, the existing MOT is still
valid and the vehicle is unlikely to be unroadworthy.

Haven't heard so much about roadside emissions stops for the last few
years, but they do include the ability to place an immediate prohibition
order on any vehicle.
https://www.transportoffice.gov.uk/c...T032945.pdf€Ž

On Thu, 12 Dec 2013 09:47:51 +0000, Nick Odell wrote:

The error code is deffo for the emission control

Does the fault code give any more detail than that? Because that's
incredibly wide ranging. If that's all it comes back with, then the cat
is about the lowest on the list of likely causes.

On Thu, 12 Dec 2013 07:45:44 +0000, Martin Brown
wrote:

On 12/12/2013 05:24, Nthkentman wrote:
Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.



Personally I would have the error code diagnosed as it might be just a
case of a failed/dis-connected sensor or something like that

Or someone has nicked his catalytic converter. There has been a spate of
it around Middlebrough recently.

This happened to my son while he was parked up in Detroit.
Fortunately, it was Detroit so getting a replacement wasn't too
difficult or expensive.

Nick

On 12/12/2013 09:49, Nick Odell wrote:
On Thu, 12 Dec 2013 07:45:44 +0000, Martin Brown
wrote:

On 12/12/2013 05:24, Nthkentman wrote:
Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.



Personally I would have the error code diagnosed as it might be just a
case of a failed/dis-connected sensor or something like that

Or someone has nicked his catalytic converter. There has been a spate of
it around Middlebrough recently.

This happened to my son while he was parked up in Detroit.
Fortunately, it was Detroit so getting a replacement wasn't too
difficult or expensive.

Maybe he even got his own one back again?



Nick

On Thu, 12 Dec 2013 09:00:33 +0000 (UTC), Adrian
wrote:

On Thu, 12 Dec 2013 01:17:54 +0000, Nick Odell wrote:

Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done by
driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of months.

Is he sure it's the cat that's failed? Has he read the fault codes?

Unless it's very very recent, not that many cars have post-cat lambdas,
which are really about the only thing that'll infallibly tell the ECU and
fault codes that the cat has failed.

If it IS the cat, and there's no post-cat lambda, then a failed cat is
unlikely to tell the ECU to slap a light up. It'll probably be fine, but
it MAY clog or break up and block the exhaust flow, reducing power
drastically and overheating the exhaust. A fire might result.

If it is the cat, and there's a post-cat lambda, then the ECU might put
the car into a limp-home mode.

If it isn't the cat, then all bets are off. It might run very rich,
drinking fuel and diluting oil. It might be the first warning of another
issue.

If he's guessing it's "just" the cat, he's probably wrong.

It's a nearly three-year-old Vauxhall Corsa so I presume, unless the
law changed (I'm a SNDB, remember) it's due for its first MOT very
soon. I'm surprised that, with all the give-aways and deals that come
with new cars that it is not still under warranty but I'm told that it
isn't so there we go.

According to the handbook, that light flashing indicates a failing
emissions control system; constantly on indicates it has failed. I'm
getting the impression that there's more to emissions control than
just the cat, right?


Will he be leaving other problems - brakes, f'rinstance - until the MOT,
under this widespread belief that the MOT is all the maintenance a car
needs?

Of course not (he says, hopefully).

Thanks for all the comments: I'll see that the owner gets to read
them.

Nick

On Thu, 12 Dec 2013 09:55:15 +0000, GB
wrote:

On 12/12/2013 09:49, Nick Odell wrote:
On Thu, 12 Dec 2013 07:45:44 +0000, Martin Brown
wrote:

On 12/12/2013 05:24, Nthkentman wrote:
Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.



Personally I would have the error code diagnosed as it might be just a
case of a failed/dis-connected sensor or something like that

Or someone has nicked his catalytic converter. There has been a spate of
it around Middlebrough recently.

This happened to my son while he was parked up in Detroit.
Fortunately, it was Detroit so getting a replacement wasn't too
difficult or expensive.

Maybe he even got his own one back again?


grin That thought did cross my mind!

N

On Thu, 12 Dec 2013 09:49:21 +0000 (UTC), Adrian
wrote:

On Thu, 12 Dec 2013 09:47:51 +0000, Nick Odell wrote:

The error code is deffo for the emission control

Does the fault code give any more detail than that? Because that's
incredibly wide ranging. If that's all it comes back with, then the cat
is about the lowest on the list of likely causes.

Only what I mentioned upthread. Back in the days when all you needed
was a good set of spanners and a feeler gauge, I used to enjoy looking
after my own bikes and cars but because I don't drive any more, I've
lost interest in the maintenance thing since the car has become
smarter than I am.

As I mentioned earlier, I'll see that the owner gets to read all this.

Thanks,

Nick

On 12/12/13 01:32, Grimly Curmudgeon wrote:
On Thu, 12 Dec 2013 01:17:54 +0000, Nick Odell
wrote:

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done
by driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of
months.

Doubt it. The engine will just keep going and if the cat's not working
(or not there) it really makes no difference to the engine. This
depends, of course, on that dash light only meaning the cat has
failed, and not something else in control of mixture.

the ECU will possibly try and compensate and that could mean extra fuel
consumption, but I doubt it would damage anything


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On 12/12/13 10:03, Nick Odell wrote:
On Thu, 12 Dec 2013 09:00:33 +0000 (UTC), Adrian
wrote:

On Thu, 12 Dec 2013 01:17:54 +0000, Nick Odell wrote:

Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done by
driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of months.

Is he sure it's the cat that's failed? Has he read the fault codes?

Unless it's very very recent, not that many cars have post-cat lambdas,
which are really about the only thing that'll infallibly tell the ECU and
fault codes that the cat has failed.

If it IS the cat, and there's no post-cat lambda, then a failed cat is
unlikely to tell the ECU to slap a light up. It'll probably be fine, but
it MAY clog or break up and block the exhaust flow, reducing power
drastically and overheating the exhaust. A fire might result.

If it is the cat, and there's a post-cat lambda, then the ECU might put
the car into a limp-home mode.

If it isn't the cat, then all bets are off. It might run very rich,
drinking fuel and diluting oil. It might be the first warning of another
issue.

If he's guessing it's "just" the cat, he's probably wrong.

It's a nearly three-year-old Vauxhall Corsa so I presume, unless the
law changed (I'm a SNDB, remember) it's due for its first MOT very
soon. I'm surprised that, with all the give-aways and deals that come
with new cars that it is not still under warranty but I'm told that it
isn't so there we go.

According to the handbook, that light flashing indicates a failing
emissions control system; constantly on indicates it has failed. I'm
getting the impression that there's more to emissions control than
just the cat, right?


sounds to me like a dodgy lambda sensor.

Could be no more than a disconnected wire corroded terminal or a failed
sensor.

I've never dealt with that fault but it is probably little more than
under the car, inspect and juggle, and at worst unscrew and replace
sensor and reconnect.

I've just thought of something though. a vague memory says that cat
converters get poisoned by working at wrong part of the curve, so if it
ain't fixed you MIGHT end up with having to get a new cat even though
existing one is actually OK.



Will he be leaving other problems - brakes, f'rinstance - until the MOT,
under this widespread belief that the MOT is all the maintenance a car
needs?

Of course not (he says, hopefully).

Thanks for all the comments: I'll see that the owner gets to read
them.

Nick



--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On 12/12/2013 09:00, Adrian wrote:

Unless it's very very recent, not that many cars have post-cat lambdas,
which are really about the only thing that'll infallibly tell the ECU and
fault codes that the cat has failed.


Some older cars did, though mostly Japanese IIRC.

It's getting worse though, my bog standard Focus has two cats and four
sensors, one pre and one post for each cat...

Lee

On 12/12/2013 10:03, Nick Odell wrote:

It's a nearly three-year-old Vauxhall Corsa so I presume, unless the
law changed (I'm a SNDB, remember) it's due for its first MOT very
soon. I'm surprised that, with all the give-aways and deals that come
with new cars that it is not still under warranty but I'm told that it
isn't so there we go.

You have to do something pretty bad not to be under warranty on a less
than three yo vauxhall.
They come with a three year warranty and the first owner gets 100,000 miles.


According to the handbook, that light flashing indicates a failing
emissions control system; constantly on indicates it has failed. I'm
getting the impression that there's more to emissions control than
just the cat, right?

One of the sensors has failed or detected an out of spec error.
The chances of the cat having failed is low but it could fail if the
other fault isn't fixed.
One way is for there to be too much unburnt fuel in the exhaust and that
can cause the cat to go pop and you get lots of expensive platinum
coated ceramic bits falling out the tail pipe. Other than poisoning it
by putting leaded fuel in I can't think of another way to kill a cat.

There are plenty of ways of killing the sensors, like silicates in the
petrol (ask Tesco about that).



What's he going to do when the MOT is up scrap the car?

On Thu, 12 Dec 2013 10:03:14 +0000, Nick Odell wrote:

It's a nearly three-year-old Vauxhall Corsa so I presume, unless the law
changed (I'm a SNDB, remember) it's due for its first MOT very soon. I'm
surprised that, with all the give-aways and deals that come with new
cars that it is not still under warranty but I'm told that it isn't so
there we go.

If he bought it new, then it's Vauxhall's infamous "lifetime", max
10yr/100k miles. If he bought it used, then it's 3yr/60k mile.

And the fault codes will most certainly say a lot more than just
"emissions fault, innit, guv?"

Either way, and to be brutally honest, he's a ****ing idiot if he's going
to sit and wait for months to get it sorted. If it was a shed being run
into the ground and scrapped if the ticket looked pricey, then I can see
the logic. But...?

In article , Lee
writes
On 12/12/2013 09:00, Adrian wrote:

Unless it's very very recent, not that many cars have post-cat lambdas,
which are really about the only thing that'll infallibly tell the ECU and
fault codes that the cat has failed.


Some older cars did, though mostly Japanese IIRC.

It's getting worse though, my bog standard Focus has two cats and four
sensors, one pre and one post for each cat...

Jeez, that's another car to avoid, wot a load of absolute ********.

Thanks for the heads-up.
--
fred
it's a ba-na-na . . . .

On 12/12/2013 15:41, fred wrote:


Jeez, that's another car to avoid, wot a load of absolute ********.

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and then
another on 3+4. Can't see the reasoning behind it at all

The Natural Philosopher submitted this idea :
I've just thought of something though. a vague memory says that cat
converters get poisoned by working at wrong part of the curve, so if it ain't
fixed you MIGHT end up with having to get a new cat even though existing one
is actually OK.

I understand the 'poisoning' can be burnt off with a torch.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Thu, 12 Dec 2013 16:39:47 +0000, Lee wrote:

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and then
another on 3+4. Can't see the reasoning behind it at all

Smaller cats, closer to the cylinders, meaning they get up to operating
temp faster.

On 12/12/2013 18:01, Adrian wrote:
On Thu, 12 Dec 2013 16:39:47 +0000, Lee wrote:

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and then
another on 3+4. Can't see the reasoning behind it at all

Smaller cats, closer to the cylinders, meaning they get up to operating
temp faster.


Ok, I suppose that makes sense.
Then I guess it's just another small step to 'as we have two cats we
have to monitor them individually for better emission control'...


Lee

On Thu, 12 Dec 2013 18:42:59 +0000, Lee wrote:

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and
then another on 3+4. Can't see the reasoning behind it at all

Smaller cats, closer to the cylinders, meaning they get up to operating
temp faster.

Ok, I suppose that makes sense.
Then I guess it's just another small step to 'as we have two cats we
have to monitor them individually for better emission control'...

The ECU probably manages the fuelling for each pair of cylinders
separately, too.

And the pre- and post-cat lambdas are so it knows/can tell you when one
cat's dead.

On 12/12/2013 14:49, Jethro_uk wrote:
On Thu, 12 Dec 2013 09:48:23 +0000, Adrian wrote:

On Thu, 12 Dec 2013 09:39:50 +0000, fred wrote:

While it may fail a roadside emissions test, the existing MOT is still
valid and the vehicle is unlikely to be unroadworthy.

Haven't heard so much about roadside emissions stops for the last few
years, but they do include the ability to place an immediate prohibition
order on any vehicle.
https://www.transportoffice.gov.uk/c...T032945.pdf€Ž

Wasn't there a plan for roadside cameras for emissions testing ? Using IR/
UV spectrum analysis ?

I did wonder how that would work - what if you lived just round the
corner from one and passed it every day just after setting off with a
cold engine, high enrichment and a cold cat?

SteveW

In message , Nick Odell
writes
On Thu, 12 Dec 2013 09:00:33 +0000 (UTC), Adrian
wrote:

On Thu, 12 Dec 2013 01:17:54 +0000, Nick Odell wrote:

Not for me but for a friend of a friend (I'm a SNDB)

Apart from being illegal, being likely to fail a roadside check and
being certain to fail an MOT, is any further damage likely to be done by
driving a car with a non-working catalytic converter? The dashboard
light says that emission control has failed but the owner would rather
just keep driving until the MOT test which is due in a couple of months.

Is he sure it's the cat that's failed? Has he read the fault codes?

Unless it's very very recent, not that many cars have post-cat lambdas,
which are really about the only thing that'll infallibly tell the ECU and
fault codes that the cat has failed.

If it IS the cat, and there's no post-cat lambda, then a failed cat is
unlikely to tell the ECU to slap a light up. It'll probably be fine, but
it MAY clog or break up and block the exhaust flow, reducing power
drastically and overheating the exhaust. A fire might result.

If it is the cat, and there's a post-cat lambda, then the ECU might put
the car into a limp-home mode.

If it isn't the cat, then all bets are off. It might run very rich,
drinking fuel and diluting oil. It might be the first warning of another
issue.

If he's guessing it's "just" the cat, he's probably wrong.

It's a nearly three-year-old Vauxhall Corsa so I presume, unless the
law changed (I'm a SNDB, remember) it's due for its first MOT very
soon. I'm surprised that, with all the give-aways and deals that come
with new cars that it is not still under warranty but I'm told that it
isn't so there we go.

According to the handbook, that light flashing indicates a failing
emissions control system; constantly on indicates it has failed. I'm
getting the impression that there's more to emissions control than
just the cat, right?


Will he be leaving other problems - brakes, f'rinstance - until the MOT,
under this widespread belief that the MOT is all the maintenance a car
needs?

Of course not (he says, hopefully).

Thanks for all the comments: I'll see that the owner gets to read
them.

Nick
Corsas (and Golfs) have a bit of a reputation for putting on the light
for no good reason. I agree with the comments that it is most likely the
sensor rather than the cat itself.
All the light tells you is that the oxygen level is out of spec - too
high or too low.
--
bert

In message om,
"dennis@home" writes
On 12/12/2013 10:03, Nick Odell wrote:

It's a nearly three-year-old Vauxhall Corsa so I presume, unless the
law changed (I'm a SNDB, remember) it's due for its first MOT very
soon. I'm surprised that, with all the give-aways and deals that come
with new cars that it is not still under warranty but I'm told that it
isn't so there we go.

You have to do something pretty bad not to be under warranty on a less
than three yo vauxhall.
They come with a three year warranty and the first owner gets 100,000 miles.


According to the handbook, that light flashing indicates a failing
emissions control system; constantly on indicates it has failed. I'm
getting the impression that there's more to emissions control than
just the cat, right?

One of the sensors has failed or detected an out of spec error.
The chances of the cat having failed is low but it could fail if the
other fault isn't fixed.

+1

One way is for there to be too much unburnt fuel in the exhaust and
that can cause the cat to go pop and you get lots of expensive platinum
coated ceramic bits falling out the tail pipe. Other than poisoning it
by putting leaded fuel in I can't think of another way to kill a cat.

There are plenty of ways of killing the sensors, like silicates in the
petrol (ask Tesco about that).



What's he going to do when the MOT is up scrap the car?



--
bert

In message , Lee
writes
On 12/12/2013 18:01, Adrian wrote:
On Thu, 12 Dec 2013 16:39:47 +0000, Lee wrote:

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and then
another on 3+4. Can't see the reasoning behind it at all

Smaller cats, closer to the cylinders, meaning they get up to operating
temp faster.


Ok, I suppose that makes sense.
Then I guess it's just another small step to 'as we have two cats we
have to monitor them individually for better emission control'...


Lee
Probably to meet latest emission specs EU4?
--
bert

On Thu, 12 Dec 2013 20:50:12 +0000, bert wrote:

Probably to meet latest emission specs EU4?

Keep up, isn't the latest for cars EU5 from 2009. EU6 is due next
year.

--
Cheers
Dave.

On Thu, 12 Dec 2013 20:46:35 +0000, bert wrote:

All the light tells you is that the oxygen level is out of spec - too
high or too low.

Nope. All the light tells you is that the ECU has logged a fault. It
might be the lambda. It might not be.

On Thu, 12 Dec 2013 18:01:16 +0000 (UTC), Adrian wrote:

On Thu, 12 Dec 2013 16:39:47 +0000, Lee wrote:

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and then
another on 3+4. Can't see the reasoning behind it at all

Smaller cats, closer to the cylinders, meaning they get up to operating
temp faster.

Can't really see it making much if any difference when they fit the cat a couple
of hand spans downstream of the exhaust valves rather than a few feet down the
exhaust pipe as they used to.

--

On Fri, 13 Dec 2013 12:23:43 +0000, The Other Mike wrote:

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and
then another on 3+4. Can't see the reasoning behind it at all

Smaller cats, closer to the cylinders, meaning they get up to operating
temp faster.

Can't really see it making much if any difference when they fit the cat
a couple of hand spans downstream of the exhaust valves rather than a
few feet down the exhaust pipe as they used to.

It'll make a very big difference.

On 13/12/13 13:32, Adrian wrote:
On Fri, 13 Dec 2013 12:23:43 +0000, The Other Mike wrote:

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and
then another on 3+4. Can't see the reasoning behind it at all

Smaller cats, closer to the cylinders, meaning they get up to operating
temp faster.

Can't really see it making much if any difference when they fit the cat
a couple of hand spans downstream of the exhaust valves rather than a
few feet down the exhaust pipe as they used to.

It'll make a very big difference.

to temperatures at least.

And to how long it takes to get to 'operational' temperatures.

The standard way to start a car - full rich mix, retarded ignition, and
cold exhaust pumps huge quantities of unburnt fuel soot and CO into the air.

For journeys under 10 miles a cat hardly is worth having in winter.

Anything you can do to preheat or shorten its heat up time is well worth it.



--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On Fri, 13 Dec 2013 13:32:40 +0000 (UTC), Adrian wrote:

On Fri, 13 Dec 2013 12:23:43 +0000, The Other Mike wrote:

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and
then another on 3+4. Can't see the reasoning behind it at all

Smaller cats, closer to the cylinders, meaning they get up to operating
temp faster.

Can't really see it making much if any difference when they fit the cat
a couple of hand spans downstream of the exhaust valves rather than a
few feet down the exhaust pipe as they used to.

It'll make a very big difference.

Maybe it was badly worded

For "when they fit the cat" substitute "when they all fit the cat"

There seems little point in keeping the exhaust streams separate and using two
cats when lots of manufacturers seem to be able to easily meet the regs with a
single cat, also very closely coupled to the cylinders.

Why increase the total external surface area of the cat housings, increasing
heat losses, when one housing, with the equivalent catalysing surface area, does
the job.



--

On 13/12/13 16:23, The Other Mike wrote:
On Fri, 13 Dec 2013 13:32:40 +0000 (UTC), Adrian wrote:

On Fri, 13 Dec 2013 12:23:43 +0000, The Other Mike wrote:

Yeah, they've done it as the manifold+cat combined thing as usual but
then decided that they need two of them. Ie one on cylinder 1+2 and
then another on 3+4. Can't see the reasoning behind it at all

Smaller cats, closer to the cylinders, meaning they get up to operating
temp faster.

Can't really see it making much if any difference when they fit the cat
a couple of hand spans downstream of the exhaust valves rather than a
few feet down the exhaust pipe as they used to.

It'll make a very big difference.

Maybe it was badly worded

For "when they fit the cat" substitute "when they all fit the cat"

There seems little point in keeping the exhaust streams separate and using two
cats when lots of manufacturers seem to be able to easily meet the regs with a
single cat, also very closely coupled to the cylinders.

Why increase the total external surface area of the cat housings, increasing
heat losses, when one housing, with the equivalent catalysing surface area, does
the job.

I can think of many reasons.
All to do with trading efficiency for cost.






--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

In message , Adrian
writes
On Thu, 12 Dec 2013 20:46:35 +0000, bert wrote:

All the light tells you is that the oxygen level is out of spec - too
high or too low.

Nope. All the light tells you is that the ECU has logged a fault. It
might be the lambda. It might not be.
The engine management light specifically refer to emissions out of spec
- according to each handbook on my 3 vehicles.
--
bert