My sister has old V6 VY Commo. Fuel economy quite bad. Runs okay, apart
from wonky idle. I noticed the end of exhaust pipe is black with soot,
so must be running rich. Also exhaust smell bad. So I changed the lambda
sensors, that is common cause of this. I expected the sensors would be
covered in soot too, but no they are light brown coating. What gives?

On 18/09/2021 10:01 am, Gary Johnson wrote:
> My sister has old V6 VY Commo.

Ecotech V6 then.

Fuel economy quite bad. Runs okay, apart
> from wonky idle.

So that's two problems right there.

Pull the plugs out and have a look to see if any stand out as different
from the others.

On 18/09/2021 12:01 pm, Gary Johnson wrote:

> My sister has old V6 VY Commo.

Pass on my sympathies.

> Fuel economy quite bad.

"Quite bad" is a pretty broad general term that doesn't really mean
much. Especially when talking about engines like these that can be
thirsty at the best of times.

Do you have a number?

> Runs okay, apart from wonky idle.

So it has one problem.....

> I noticed the end  of exhaust pipe is black with soot,
> so must be running rich.

It _may_ be, but black exhaust pipes are not uncommon.

> Also exhaust smell bad.

Again, there's that subjectivity rearing it's ugly head.

> So I changed the lambda sensors, that is common cause of this.

Common cause of what? You haven't actually established if there's a
problem that needs to be addressed yet :)

> I expected the sensors would be
> covered in soot too, but no they are light brown coating. What gives?

Lambda sensors tend to get very very hot thanks to them being located at
a point in the exhaust system where the pulses from each cylinder (or
each cylinder in a bank) collect at a common point, and as such you
can't use their colour as a guide to mixture settings. If you want to
use colourings to determine mixture settings then you'll need to learn
to read spark plugs, but as this is something the average person cannot
learn to do in five minutes you'll need to try other methods.

To answer the question you asked in the header of your post, the simple
answer is "yes, excessively rich mixtures will produce soot". However,
whether that answer has any relevance to you and your problem is
impossible to say because you haven't produced enough information to
paint a clear picture.

To get a better idea as to whether a problem even exists you need to
provide more detail. Such as the mileage of the engine. Does it get hot?
Does it get to run decent trips at normal operating temperature or does
it spend it's life doing short hops where it's always cold? Does it use
oil? Can you be more descriptive of the idle problem other than it being
"wonky"? and probably most importantly can you give a figure as to what
kind of mileage it actually gets?

Knowing the answers to these things will help determine if you have a
problem that needs correcting, or if it's just a "Holden" thing.

--
--
--
Regards,
Noddy.

On 18/09/2021 1:29 pm, Noddy wrote:
> On 18/09/2021 12:01 pm, Gary Johnson wrote:
>
>> My sister has old V6 VY Commo.
>
> Pass on my sympathies.
>
>> Fuel economy quite bad.
>
> "Quite bad" is a pretty broad general term that doesn't really mean
> much. Especially when talking about engines like these that can be
> thirsty at the best of times.
>

They're not "thirsty at the best of times", at the best of times they
are quite economical for what they are. It depends entirely on how she
drives it, what kind of driving she does and what fuel she puts in it.

I agree that "quite bad" doesn't mean anything.

On Sat, 18 Sep 2021 15:29:34 +1000, Noddy wrote:

> On 18/09/2021 12:01 pm, Gary Johnson wrote:
>
>> My sister has old V6 VY Commo.
>
> Pass on my sympathies.
>
>> Fuel economy quite bad.
>
> "Quite bad" is a pretty broad general term that doesn't really mean
> much. Especially when talking about engines like these that can be
> thirsty at the best of times.
>
> Do you have a number?
>
>> Runs okay, apart from wonky idle.
>
> So it has one problem.....
>
>> I noticed the end  of exhaust pipe is black with soot,
>> so must be running rich.
>
> It _may_ be, but black exhaust pipes are not uncommon.
>
>> Also exhaust smell bad.
>
> Again, there's that subjectivity rearing it's ugly head.
>
>> So I changed the lambda sensors, that is common cause of this.
>
> Common cause of what? You haven't actually established if there's a
> problem that needs to be addressed yet :)

The Fraudster's years of experience (snigger) as a service manager really
shine through...

alvey

Noddy wrote:
>
> To get a better idea as to whether a problem even exists you need to
> provide more detail. Such as the mileage of the engine. Does it get hot?
> Does it get to run decent trips at normal operating temperature or does
> it spend it's life doing short hops where it's always cold? Does it use
> oil? Can you be more descriptive of the idle problem other than it being
> "wonky"? and probably most importantly can you give a figure as to what
> kind of mileage it actually gets?
>
> Knowing the answers to these things will help determine if you have a
> problem that needs correcting, or if it's just a "Holden" thing.
>

The car has done 154 thou km. Was regularly serviced until my sister
retired early 2020. Since then just goes to local IGA once a week.
It is not burning oil, leaking oil or anything else. Is in pretty good
nick otherwise.
Anyway after replacing sensors, I drove it around for half an hour for
the ECU to update the trim table. It now idles steadily, but seems to
have less power, which suggests to me too rich before. I do not have
OBD scan tool that works with Holden's stupid ALDL system.

On 19/9/21 10:15 am, Gary Johnson wrote:
> Noddy wrote:
>>
>> To get a better idea as to whether a problem even exists you need to
>> provide more detail. Such as the mileage of the engine. Does it get
>> hot? Does it get to run decent trips at normal operating temperature
>> or does it spend it's life doing short hops where it's always cold?
>> Does it use oil? Can you be more descriptive of the idle problem other
>> than it being "wonky"? and probably most importantly can you give a
>> figure as to what kind of mileage it actually gets?
>>
>> Knowing the answers to these things will help determine if you have a
>> problem that needs correcting, or if it's just a "Holden" thing.
>>
>
> The car has done 154 thou km. Was regularly serviced until my sister
> retired early 2020. Since then just goes to local IGA once a week.
> It is not burning oil, leaking oil or anything else. Is in pretty good
> nick otherwise.
> Anyway after replacing sensors, I drove it around for half an hour for
> the ECU to update the trim table. It now idles steadily, but seems to
> have less power, which suggests to me too rich before. I do not have
> OBD scan tool that works with Holden's stupid ALDL system.

Sounds like it just needs a good long run.
Going to IGA once a week won't be doing it any good, probably doesn't
reach operating temp.
When were the spark plugs last replaced?
I replaced the plugs on my old Benz when I first bought it and it made a
huge difference, looked like they hadn't been replaced for a very long time.

--
Daryl

On 9/19/2021 12:02 PM, Daryl wrote:
> On 19/9/21 10:15 am, Gary Johnson wrote:
>> Noddy wrote:
>>>
>>> To get a better idea as to whether a problem even exists you need to
>>> provide more detail. Such as the mileage of the engine. Does it get
>>> hot? Does it get to run decent trips at normal operating temperature
>>> or does it spend it's life doing short hops where it's always cold?
>>> Does it use oil? Can you be more descriptive of the idle problem
>>> other than it being "wonky"? and probably most importantly can you
>>> give a figure as to what kind of mileage it actually gets?
>>>
>>> Knowing the answers to these things will help determine if you have
>>> a problem that needs correcting, or if it's just a "Holden" thing.
>>>
>>
>> The car has done 154 thou km. Was regularly serviced until my sister
>> retired early 2020. Since then just goes to local IGA once a week.
>> It is not burning oil, leaking oil or anything else. Is in pretty good
>> nick otherwise.
>> Anyway after replacing sensors, I drove it around for half an hour for
>> the ECU to update the trim table. It now idles steadily, but seems to
>> have less power, which suggests to me too rich before. I do not have
>> OBD scan tool that works with Holden's stupid ALDL system.
>
> Sounds like it just needs a good long run.
> Going to IGA once a week won't be doing it any good, probably doesn't
> reach operating temp.
> When were the spark plugs last replaced?
> I replaced the plugs on my old Benz when I first bought it and it made
> a huge difference, looked like they hadn't been replaced for a very
> long time.

~~~~~~

   Yep, blow *the cobwebs out* as the saying goes. ;)

>
>

--
"Usenet is like a herd of performing elephants with diarrhea. Massive,
difficult to redirect, awe-inspiring, entertaining, and a source of
mind-boggling amounts of excrement when you least expect it." — Gene
Spafford, 1992

On 19/09/2021 12:02 pm, Daryl wrote:
> On 19/9/21 10:15 am, Gary Johnson wrote:

>>
>> The car has done 154 thou km. Was regularly serviced until my sister
>> retired early 2020. Since then just goes to local IGA once a week.
>> It is not burning oil, leaking oil or anything else. Is in pretty good
>> nick otherwise.
>> Anyway after replacing sensors, I drove it around for half an hour for
>> the ECU to update the trim table. It now idles steadily, but seems to
>> have less power, which suggests to me too rich before. I do not have
>> OBD scan tool that works with Holden's stupid ALDL system.
>
> Sounds like it just needs a good long run.
> Going to IGA once a week won't be doing it any good, probably doesn't
> reach operating temp.

He still hasn't come back with a figure, in which case he, or anyone
else, has no idea if it's running right or not.

--
--
--
Regards,
Noddy.

On 19/09/2021 8:15 am, Gary Johnson wrote:
> Noddy wrote:
>>
>> To get a better idea as to whether a problem even exists you need to
>> provide more detail. Such as the mileage of the engine. Does it get
>> hot? Does it get to run decent trips at normal operating temperature
>> or does it spend it's life doing short hops where it's always cold?
>> Does it use oil? Can you be more descriptive of the idle problem other
>> than it being "wonky"? and probably most importantly can you give a
>> figure as to what kind of mileage it actually gets?
>>
>> Knowing the answers to these things will help determine if you have a
>> problem that needs correcting, or if it's just a "Holden" thing.
>>
>
> The car has done 154 thou km. Was regularly serviced until my sister
> retired early 2020. Since then just goes to local IGA once a week.
> It is not burning oil, leaking oil or anything else. Is in pretty good
> nick otherwise.
> Anyway after replacing sensors, I drove it around for half an hour for
> the ECU to update the trim table. It now idles steadily, but seems to
> have less power, which suggests to me too rich before. I do not have
> OBD scan tool that works with Holden's stupid ALDL system.

The power train is OBD but that doesn't help you if you don't have the
tool that supports the mish-mash that existed before Australia became
OBD-II compliant.

Maybe an Italian tune-up will do it wonders ;-)

On 19/9/21 12:25 pm, Noddy wrote:
> On 19/09/2021 12:02 pm, Daryl wrote:
>> On 19/9/21 10:15 am, Gary Johnson wrote:
>
>>>
>>> The car has done 154 thou km. Was regularly serviced until my sister
>>> retired early 2020. Since then just goes to local IGA once a week.
>>> It is not burning oil, leaking oil or anything else. Is in pretty good
>>> nick otherwise.
>>> Anyway after replacing sensors, I drove it around for half an hour for
>>> the ECU to update the trim table. It now idles steadily, but seems to
>>> have less power, which suggests to me too rich before. I do not have
>>> OBD scan tool that works with Holden's stupid ALDL system.
>>
>> Sounds like it just needs a good long run.
>> Going to IGA once a week won't be doing it any good, probably doesn't
>> reach operating temp.
>
> He still hasn't come back with a figure, in which case he, or anyone
> else, has no idea if it's running right or not.
>
>

True, the economy of those engines was pretty good on a long cruise but
not so good on short trips, as you say without numbers its impossible to
know whether or not there is actually a problem.

--
Daryl

On 9/19/2021 2:56 PM, Daryl wrote:
> On 19/9/21 12:25 pm, Noddy wrote:
>> On 19/09/2021 12:02 pm, Daryl wrote:
>>> On 19/9/21 10:15 am, Gary Johnson wrote:
>>
>>>>
>>>> The car has done 154 thou km. Was regularly serviced until my
>>>> sister retired early 2020. Since then just goes to local IGA once a
>>>> week.
>>>> It is not burning oil, leaking oil or anything else. Is in pretty good
>>>> nick otherwise.
>>>> Anyway after replacing sensors, I drove it around for half an hour for
>>>> the ECU to update the trim table. It now idles steadily, but seems to
>>>> have less power, which suggests to me too rich before. I do not have
>>>> OBD scan tool that works with Holden's stupid ALDL system.
>>>
>>> Sounds like it just needs a good long run.
>>> Going to IGA once a week won't be doing it any good, probably
>>> doesn't reach operating temp.
>>
>> He still hasn't come back with a figure, in which case he, or anyone
>> else, has no idea if it's running right or not.
>>
>>
>
> True, the economy of those engines was pretty good on a long cruise
> but not so good on short trips, as you say without numbers its
> impossible to know whether or not there is actually a problem.

~~~~~~~~~~~~~~~~

 As I said a good run with some give it the berries stuff included.

plugs (if needed) and cleaning the T/B before a run would`nt hurt
either...Numbers not needed for that! If no change (or little) *then* go
deeper.

>
>

--
"Usenet is like a herd of performing elephants with diarrhea. Massive,
difficult to redirect, awe-inspiring, entertaining, and a source of
mind-boggling amounts of excrement when you least expect it." — Gene
Spafford, 1992