aarcuda69062

In article <tbGrf.7469$ka.832@tornado.socal.rr.com>,
"Shoe Salesman" <someone@microsoft.com> wrote:

> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
> news:nonelson-35E9A0.16501325122005@newsclstr02.news.prodigy.com...
> > In article <H_Crf.6351$pE4.3438@tornado.socal.rr.com>,
> > "Shoe Salesman" <someone@microsoft.com> wrote:
> >
> >> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
> >> news:nonelson-5C139A.13525925122005@newsclstr02.news.prodigy.com...
> >> > In article <9ICrf.7450$ka.1602@tornado.socal.rr.com>,
> >> > "Shoe Salesman" <someone@microsoft.com> wrote:
> >> >
> >> >> "Tom Adkins" <newton5@remove.comcast.net> wrote in message
> >> >> news:hPadnbM-rdbooDPenZ2dnUVZ_tqdnZ2d@comcast.com...
> >> >> > Shoe Salesman wrote:
> >> >> >
> >> >> >
> >> >> >> I think you got it backwards, can't pump air into the manifold
> >> >> >> above
> >> >> >> the
> >> >> >> O2 in closed loop, it would read too much O2. It will go upstream
> >> >> >> when
> >> >> >> cold, then downstream when hot. Sounds like it could be a CA only
> >> >> >> thing
> >> >> >> too. I think I would have a muffler shop weld the pipe on it, or
> >> >> >> better
> >> >> >> yet, get the correct part.
> >> >> >>
> >> >> >
> >> >> >
> >> >> >
> >> >> > Nope Shoe,
> >> >> > Jim has it right. The air is diverted to the cats during warmup to
> >> >> > help
> >> >> > light off the cats quicker, then diverted to the manifolds to help
> >> >> > burn
> >> >> > off unburned HCs before the exhaust reaches the cats.
> >> >>
> >> >> Ok, so, he said its a straight 6 right? So its got 1 manifold right?
> >> >> Its
> >> >> got
> >> >> an O2 sensor in that manifold (or just below it). How can you pump air
> >> >> into
> >> >> the manifold (when its warmed up) and not give the O2 false info?
> >> >
> >> > By programming the PCM to ignore O2 sensor signals under
> >> > conditions when air is being injected upstream.
> >> >
> >> > Notice that in Jim and Tom's replies the absence of the word
> >> > 'always.'
> >>
> >> So its downstream when cold then diverted to atmosphere when it reaches
> >> norm operating temp, exept under certain conditions? What are those
> >> conditions?
> >
> > Your question was;
> > "How can you pump air into
> > the manifold (when its warmed up) and not give the O2 false
> > info?"
> >
> > I gave you the answer.
> > The rest has already been covered.
>
> No, I just asked what those conditions were. What was covered was when
> warmed up, it goes to the manifold. Then you said not "always". What I want
> to know is the "not always" part when its warm.

Please refrain from misquoting me.
I did not say "not always." I said that Jim and Tom's replies
did not contain the word "always."
If what was covered (by your admission) was when warmed up, what
more needs to be said?

> When during closed loop does
> the ECM not look at the O2 (when is it injecting air in the manifold in
> closed loop) like you said?

Who said anything about "closed loop?"
Do you understand what "closed loop" means?
If you did, you wouldn't have made that statement.

> If you don't know just say so, I'm just trying
> to learn about the system here....

Forget the "system," work on the basics first.
a) closed loop versus open loop
b) cold operation versus warm operation
c) purpose of the oxygen sensor

 

Jim Warman

Back before EFI and fedback carbs, we didn't really have to think much about
it...... under decelleration, the air would be diverted away from the
exhaust to prevent backfires. As far as vehicles presently being
manufactured, I don't know of any with a A.I.R. type system.... though many
have electrical secondary air pumps to supply air to the cats to "light them
off".

This is a long drawn out way of saying that I am unsure of the operating
strategy of the system..... I will say that the pumps were sized for the
application.... I will say that many times I have felt and/or heard diverted
air coming from the fenderwell mounted muffler.... without giving it a
second thought simply because the system was working. Remember that these
old systems were, by and large, speed density systems..... The PCM knew the
engine displacement, it knew the throttle opening, it knew barometric
pressure and intake manifold vacuum as well as engine rpm - more than enough
info to establish a reasonable fuel mixture. Taken one step further, the
engineers knew the size of the pump and the ratio of the pulleys... (this is
assumption and home grown rationalization).... based on this, the engineers
know how much air is being commanded where... and adjust programming to
suit.

With the level that todays technology has attained..... all I can say is
that some of the mandatory courses I take are enough to give you a really
good immitation of a migraine.

To indicate how prehistoric our early attempts at feedback fuel control
were..... my 1985 F150 4X4 had the EFI 302..... Thermactor pump installed
(even in Canada) With a single O2 sensor planted at the back of one exhaust
manifold. Chevrolet did the same with their pick ups.... Some had air pumps,
some didn't but they all had one single O2 sensor at the rear of one
manifold. Dodge muddied the waters even more.... on their pick ups, they
went with a "pulsed air" system..... There was no air pump but, instead,
there were one way check valves (identical to the antibackfire valves in the
GM and Ford systems)that allowed atmospheric pressure into the exhaust ....
remembering that each positive pressure wave in the exhaust is followed by a
negative pressure wave. The Japs used this system for many years with good
success.

Now... if anyone noticed, I always refer to pick ups of all sorts and
sizes.... I live in a very small (but growing) town in the middle of the
great Canadian arboreal forest..... I don't get to work on cars very often
(which is a good thing... I'm fat enough and old enough that you need a
stick of butter and a shoehorn to get me in and out of them). As far as
early emissions controls, Canada was a redheaded cousin.... in most cases,
we lagged behind the US about 3 years. This made for a repair manual
nightmare as we searched for anything pertinent to the vehicle we were
working on. In other cases, we never did see some of the stuff that was made
(and failed) in the states.

I realize that this is a pretty long dissertation... but, hey.... It's
Christmas and we can only watch "Miracle On 34th Streeet" so many times....

Shoe Salesman

"aarcuda69062" <nonelson@sbcglobal.net> wrote in message
news:nonelson-600893.21254125122005@newsclstr02.news.prodigy.com...
> In article <tbGrf.7469$ka.832@tornado.socal.rr.com>,
> "Shoe Salesman" <someone@microsoft.com> wrote:
>
>> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
>> news:nonelson-35E9A0.16501325122005@newsclstr02.news.prodigy.com...
>> > In article <H_Crf.6351$pE4.3438@tornado.socal.rr.com>,
>> > "Shoe Salesman" <someone@microsoft.com> wrote:
>> >
>> >> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
>> >> news:nonelson-5C139A.13525925122005@newsclstr02.news.prodigy.com...
>> >> > In article <9ICrf.7450$ka.1602@tornado.socal.rr.com>,
>> >> > "Shoe Salesman" <someone@microsoft.com> wrote:
>> >> >
>> >> >> "Tom Adkins" <newton5@remove.comcast.net> wrote in message
>> >> >> news:hPadnbM-rdbooDPenZ2dnUVZ_tqdnZ2d@comcast.com...
>> >> >> > Shoe Salesman wrote:
>> >> >> >
>> >> >> >
>> >> >> >> I think you got it backwards, can't pump air into the manifold
>> >> >> >> above
>> >> >> >> the
>> >> >> >> O2 in closed loop, it would read too much O2. It will go
>> >> >> >> upstream
>> >> >> >> when
>> >> >> >> cold, then downstream when hot. Sounds like it could be a CA
>> >> >> >> only
>> >> >> >> thing
>> >> >> >> too. I think I would have a muffler shop weld the pipe on it, or
>> >> >> >> better
>> >> >> >> yet, get the correct part.
>> >> >> >>
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> > Nope Shoe,
>> >> >> > Jim has it right. The air is diverted to the cats during warmup
>> >> >> > to
>> >> >> > help
>> >> >> > light off the cats quicker, then diverted to the manifolds to
>> >> >> > help
>> >> >> > burn
>> >> >> > off unburned HCs before the exhaust reaches the cats.
>> >> >>
>> >> >> Ok, so, he said its a straight 6 right? So its got 1 manifold
>> >> >> right?
>> >> >> Its
>> >> >> got
>> >> >> an O2 sensor in that manifold (or just below it). How can you pump
>> >> >> air
>> >> >> into
>> >> >> the manifold (when its warmed up) and not give the O2 false info?
>> >> >
>> >> > By programming the PCM to ignore O2 sensor signals under
>> >> > conditions when air is being injected upstream.
>> >> >
>> >> > Notice that in Jim and Tom's replies the absence of the word
>> >> > 'always.'
>> >>
>> >> So its downstream when cold then diverted to atmosphere when it
>> >> reaches
>> >> norm operating temp, exept under certain conditions? What are those
>> >> conditions?
>> >
>> > Your question was;
>> > "How can you pump air into
>> > the manifold (when its warmed up) and not give the O2 false
>> > info?"
>> >
>> > I gave you the answer.
>> > The rest has already been covered.
>>
>> No, I just asked what those conditions were. What was covered was when
>> warmed up, it goes to the manifold. Then you said not "always". What I
>> want
>> to know is the "not always" part when its warm.
>
> Please refrain from misquoting me.
> I did not say "not always." I said that Jim and Tom's replies
> did not contain the word "always."
> If what was covered (by your admission) was when warmed up, what
> more needs to be said?
>
>> When during closed loop does
>> the ECM not look at the O2 (when is it injecting air in the manifold in
>> closed loop) like you said?
>
> Who said anything about "closed loop?"
> Do you understand what "closed loop" means?
> If you did, you wouldn't have made that statement.
>
>> If you don't know just say so, I'm just trying
>> to learn about the system here....
>
> Forget the "system," work on the basics first.
> a) closed loop versus open loop
> b) cold operation versus warm operation
> c) purpose of the oxygen sensor

You know what aarcuba, I'm thinking you don't know how it works and your
just trying to sound like you do. I know very well the "basics" you listed
above. My question was: Its got an O2 sensor in that manifold (or just below
it). How can you pump air into the manifold (when its warmed up) and not
give the O2 false info? You replied, "By programming the PCM to ignore O2
sensor signals under conditions when air is being injected upstream." Again,
my question was simple....what are those conditions? Let me give you a few
examples so you won't be confused:

1. On decel
2. At WOT.
3. At cruise.
4. At no time when the vehicle is in closed loop will the air be diverted to
the manifold, I was wrong, it diverts it to atmosphere.
5. At no time when the vehicle is in closed loop, I was wrong, it diverts
downstream.
6. I have no idea, all I know is the basics.
7. I will come up with a smart ass answer to try and look smart like: When
it ignores the O2 it's not *really* in closed loop. Or, you just said
"warmed up" not closed loop.
8. I will turn this into an argument about closed loop instead, so people
don't know that all I know is the basics.

I'm thinking the real answer is either #4 and/or 5 AND 6. But you will come
up with something like 6, 7, or 8.

Shoe Salesman

"Jim Warman" <mechanic@telusplanet.net> wrote in message
news:3ZJrf.6594$km.4716@edtnps89...
> Back before EFI and fedback carbs, we didn't really have to think much
> about it...... under decelleration, the air would be diverted away from
> the exhaust to prevent backfires. As far as vehicles presently being
> manufactured, I don't know of any with a A.I.R. type system.... though
> many have electrical secondary air pumps to supply air to the cats to
> "light them off".
>
> This is a long drawn out way of saying that I am unsure of the operating
> strategy of the system..... I will say that the pumps were sized for the
> application.... I will say that many times I have felt and/or heard
> diverted air coming from the fenderwell mounted muffler.... without giving
> it a second thought simply because the system was working. Remember that
> these old systems were, by and large, speed density systems..... The PCM
> knew the engine displacement, it knew the throttle opening, it knew
> barometric pressure and intake manifold vacuum as well as engine rpm -
> more than enough info to establish a reasonable fuel mixture. Taken one
> step further, the engineers knew the size of the pump and the ratio of the
> pulleys... (this is assumption and home grown rationalization).... based
> on this, the engineers know how much air is being commanded where... and
> adjust programming to suit.
>
> With the level that todays technology has attained..... all I can say is
> that some of the mandatory courses I take are enough to give you a really
> good immitation of a migraine.
>
> To indicate how prehistoric our early attempts at feedback fuel control
> were..... my 1985 F150 4X4 had the EFI 302..... Thermactor pump installed
> (even in Canada) With a single O2 sensor planted at the back of one
> exhaust manifold. Chevrolet did the same with their pick ups.... Some had
> air pumps, some didn't but they all had one single O2 sensor at the rear
> of one manifold. Dodge muddied the waters even more.... on their pick ups,
> they went with a "pulsed air" system..... There was no air pump but,
> instead, there were one way check valves (identical to the antibackfire
> valves in the GM and Ford systems)that allowed atmospheric pressure into
> the exhaust .... remembering that each positive pressure wave in the
> exhaust is followed by a negative pressure wave. The Japs used this system
> for many years with good success.
>
> Now... if anyone noticed, I always refer to pick ups of all sorts and
> sizes.... I live in a very small (but growing) town in the middle of the
> great Canadian arboreal forest..... I don't get to work on cars very often
> (which is a good thing... I'm fat enough and old enough that you need a
> stick of butter and a shoehorn to get me in and out of them). As far as
> early emissions controls, Canada was a redheaded cousin.... in most cases,
> we lagged behind the US about 3 years. This made for a repair manual
> nightmare as we searched for anything pertinent to the vehicle we were
> working on. In other cases, we never did see some of the stuff that was
> made (and failed) in the states.
>
> I realize that this is a pretty long dissertation... but, hey.... It's
> Christmas and we can only watch "Miracle On 34th Streeet" so many
> times....
>
>
Thanks for the real info Jim. I had the opposite problem in a since, fixing
and smog testing cars in Ca -the king of emission controls state. Its been a
long time since I've worked on a 90 or so vintage Ford p/u s but I do recall
the downstream pipe. During a smog check you were not required to test the
AIR system, you just had to make sure it was all there and not obviously
modified. If something was wrong it would probably fail the tailpipe part of
the test anyway. I also remember Chevys that would/or should only pump air
to the manifold before it was warmed up and in closed loop. It wasn't
uncommon for them to pump air upsteam and cause the car to fail because of
high CO. I think some V8s had the O2 on one bank and the AIR manifold on the
other(IIRC) to eliminate that problem I guess. Like you said, looks like
the "smog pump" is gone. :)

aarcuda69062

In article <HTLrf.6373$pE4.5120@tornado.socal.rr.com>,
"Shoe Salesman" <someone@microsoft.com> wrote:

> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
> news:nonelson-600893.21254125122005@newsclstr02.news.prodigy.com...
> > In article <tbGrf.7469$ka.832@tornado.socal.rr.com>,
> > "Shoe Salesman" <someone@microsoft.com> wrote:
> >
> >> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
> >> news:nonelson-35E9A0.16501325122005@newsclstr02.news.prodigy.com...
> >> > In article <H_Crf.6351$pE4.3438@tornado.socal.rr.com>,
> >> > "Shoe Salesman" <someone@microsoft.com> wrote:
> >> >
> >> >> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
> >> >> news:nonelson-5C139A.13525925122005@newsclstr02.news.prodigy.com...
> >> >> > In article <9ICrf.7450$ka.1602@tornado.socal.rr.com>,
> >> >> > "Shoe Salesman" <someone@microsoft.com> wrote:
> >> >> >
> >> >> >> "Tom Adkins" <newton5@remove.comcast.net> wrote in message
> >> >> >> news:hPadnbM-rdbooDPenZ2dnUVZ_tqdnZ2d@comcast.com...
> >> >> >> > Shoe Salesman wrote:
> >> >> >> >
> >> >> >> >
> >> >> >> >> I think you got it backwards, can't pump air into the manifold
> >> >> >> >> above
> >> >> >> >> the
> >> >> >> >> O2 in closed loop, it would read too much O2. It will go
> >> >> >> >> upstream
> >> >> >> >> when
> >> >> >> >> cold, then downstream when hot. Sounds like it could be a CA
> >> >> >> >> only
> >> >> >> >> thing
> >> >> >> >> too. I think I would have a muffler shop weld the pipe on it, or
> >> >> >> >> better
> >> >> >> >> yet, get the correct part.
> >> >> >> >>
> >> >> >> >
> >> >> >> >
> >> >> >> >
> >> >> >> > Nope Shoe,
> >> >> >> > Jim has it right. The air is diverted to the cats during warmup
> >> >> >> > to
> >> >> >> > help
> >> >> >> > light off the cats quicker, then diverted to the manifolds to
> >> >> >> > help
> >> >> >> > burn
> >> >> >> > off unburned HCs before the exhaust reaches the cats.
> >> >> >>
> >> >> >> Ok, so, he said its a straight 6 right? So its got 1 manifold
> >> >> >> right?
> >> >> >> Its
> >> >> >> got
> >> >> >> an O2 sensor in that manifold (or just below it). How can you pump
> >> >> >> air
> >> >> >> into
> >> >> >> the manifold (when its warmed up) and not give the O2 false info?
> >> >> >
> >> >> > By programming the PCM to ignore O2 sensor signals under
> >> >> > conditions when air is being injected upstream.
> >> >> >
> >> >> > Notice that in Jim and Tom's replies the absence of the word
> >> >> > 'always.'
> >> >>
> >> >> So its downstream when cold then diverted to atmosphere when it
> >> >> reaches
> >> >> norm operating temp, exept under certain conditions? What are those
> >> >> conditions?
> >> >
> >> > Your question was;
> >> > "How can you pump air into
> >> > the manifold (when its warmed up) and not give the O2 false
> >> > info?"
> >> >
> >> > I gave you the answer.
> >> > The rest has already been covered.
> >>
> >> No, I just asked what those conditions were. What was covered was when
> >> warmed up, it goes to the manifold. Then you said not "always". What I
> >> want
> >> to know is the "not always" part when its warm.
> >
> > Please refrain from misquoting me.
> > I did not say "not always." I said that Jim and Tom's replies
> > did not contain the word "always."
> > If what was covered (by your admission) was when warmed up, what
> > more needs to be said?
> >
> >> When during closed loop does
> >> the ECM not look at the O2 (when is it injecting air in the manifold in
> >> closed loop) like you said?
> >
> > Who said anything about "closed loop?"
> > Do you understand what "closed loop" means?
> > If you did, you wouldn't have made that statement.
> >
> >> If you don't know just say so, I'm just trying
> >> to learn about the system here....
> >
> > Forget the "system," work on the basics first.
> > a) closed loop versus open loop
> > b) cold operation versus warm operation
> > c) purpose of the oxygen sensor
>
> You know what aarcuba, I'm thinking you don't know how it works and your
> just trying to sound like you do. I know very well the "basics" you listed
> above. My question was: Its got an O2 sensor in that manifold (or just below
> it). How can you pump air into the manifold (when its warmed up) and not
> give the O2 false info? You replied, "By programming the PCM to ignore O2
> sensor signals under conditions when air is being injected upstream." Again,
> my question was simple....what are those conditions? Let me give you a few
> examples so you won't be confused:
>
> 1. On decel

It should be obvious that pumping air into the exhaust manifold
during decel would cause afterburn up to and including the point
where the muffler is split open.

> 2. At WOT.

O2 is ignored during WOT, so yes, it could be done then.

> 3. At cruise.

If that's what the engineers choose.

> 4. At no time when the vehicle is in closed loop will the air be diverted to
> the manifold, I was wrong, it diverts it to atmosphere.

By definition, if it's in closed loop the O2 isn't being ignored.

> 5. At no time when the vehicle is in closed loop, I was wrong, it diverts
> downstream.

By definition, if it's in closed loop the O2 isn't being ignored.

> 6. I have no idea, all I know is the basics.

Read a book then.

> 7. I will come up with a smart ass answer to try and look smart like: When
> it ignores the O2 it's not *really* in closed loop.

That would be a fact. The system can NOT ignore the O2 -and- be
in closed loop. If you have a problem with this, then you don't
understand closed loop, you don't understand the basics.

> Or, you just said
> "warmed up" not closed loop.

They are two entirely different things, just like an engine can
be not warmed up and in closed loop.

> 8. I will turn this into an argument about closed loop instead, so people
> don't know that all I know is the basics.

Feel free.

> I'm thinking the real answer is either #4 and/or 5 AND 6. But you will come
> up with something like 6, 7, or 8.

Well, if you're smart enough to claim that I don't know how it
works, why are you asking such basic questions and more
importantly, why are your questions seasoned with
misunderstanding?

I think the answer you're looking for is;
any time there is excess CO or HC in the exhaust that would not
be scrubbed by the catalytic convertor due to any number of
factors such as, WOT, a cooled off cat, insufficient oxygen to
the cat to support oxidation, during a hot restart when fuel
vapors may be high, etc.

aarcuda69062

In article <TnMrf.6375$pE4.6046@tornado.socal.rr.com>,
"Shoe Salesman" <someone@microsoft.com> wrote:

> Thanks for the real info Jim. I had the opposite problem in a since, fixing
> and smog testing cars in Ca -the king of emission controls state. Its been a
> long time since I've worked on a 90 or so vintage Ford p/u s but I do recall
> the downstream pipe. During a smog check you were not required to test the
> AIR system, you just had to make sure it was all there and not obviously
> modified. If something was wrong it would probably fail the tailpipe part of
> the test anyway. I also remember Chevys that would/or should only pump air
> to the manifold before it was warmed up and in closed loop. It wasn't
> uncommon for them to pump air upsteam and cause the car to fail because of
> high CO. I think some V8s had the O2 on one bank and the AIR manifold on the
> other(IIRC) to eliminate that problem I guess. Like you said, looks like
> the "smog pump" is gone. :)

Ford's air pump strategy is not the same as what GM does.

Shoe Salesman

"aarcuda69062" <nonelson@sbcglobal.net> wrote in message
news:nonelson-BA54FD.02231826122005@newsclstr02.news.prodigy.com...
> In article <HTLrf.6373$pE4.5120@tornado.socal.rr.com>,
> "Shoe Salesman" <someone@microsoft.com> wrote:
>
>> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
>> news:nonelson-600893.21254125122005@newsclstr02.news.prodigy.com...
>> > In article <tbGrf.7469$ka.832@tornado.socal.rr.com>,
>> > "Shoe Salesman" <someone@microsoft.com> wrote:
>> >
>> >> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
>> >> news:nonelson-35E9A0.16501325122005@newsclstr02.news.prodigy.com...
>> >> > In article <H_Crf.6351$pE4.3438@tornado.socal.rr.com>,
>> >> > "Shoe Salesman" <someone@microsoft.com> wrote:
>> >> >
>> >> >> "aarcuda69062" <nonelson@sbcglobal.net> wrote in message
>> >> >> news:nonelson-5C139A.13525925122005@newsclstr02.news.prodigy.com...
>> >> >> > In article <9ICrf.7450$ka.1602@tornado.socal.rr.com>,
>> >> >> > "Shoe Salesman" <someone@microsoft.com> wrote:
>> >> >> >
>> >> >> >> "Tom Adkins" <newton5@remove.comcast.net> wrote in message
>> >> >> >> news:hPadnbM-rdbooDPenZ2dnUVZ_tqdnZ2d@comcast.com...
>> >> >> >> > Shoe Salesman wrote:
>> >> >> >> >
>> >> >> >> >
>> >> >> >> >> I think you got it backwards, can't pump air into the
>> >> >> >> >> manifold
>> >> >> >> >> above
>> >> >> >> >> the
>> >> >> >> >> O2 in closed loop, it would read too much O2. It will go
>> >> >> >> >> upstream
>> >> >> >> >> when
>> >> >> >> >> cold, then downstream when hot. Sounds like it could be a CA
>> >> >> >> >> only
>> >> >> >> >> thing
>> >> >> >> >> too. I think I would have a muffler shop weld the pipe on it,
>> >> >> >> >> or
>> >> >> >> >> better
>> >> >> >> >> yet, get the correct part.
>> >> >> >> >>
>> >> >> >> >
>> >> >> >> >
>> >> >> >> >
>> >> >> >> > Nope Shoe,
>> >> >> >> > Jim has it right. The air is diverted to the cats during
>> >> >> >> > warmup
>> >> >> >> > to
>> >> >> >> > help
>> >> >> >> > light off the cats quicker, then diverted to the manifolds to
>> >> >> >> > help
>> >> >> >> > burn
>> >> >> >> > off unburned HCs before the exhaust reaches the cats.
>> >> >> >>
>> >> >> >> Ok, so, he said its a straight 6 right? So its got 1 manifold
>> >> >> >> right?
>> >> >> >> Its
>> >> >> >> got
>> >> >> >> an O2 sensor in that manifold (or just below it). How can you
>> >> >> >> pump
>> >> >> >> air
>> >> >> >> into
>> >> >> >> the manifold (when its warmed up) and not give the O2 false
>> >> >> >> info?
>> >> >> >
>> >> >> > By programming the PCM to ignore O2 sensor signals under
>> >> >> > conditions when air is being injected upstream.
>> >> >> >
>> >> >> > Notice that in Jim and Tom's replies the absence of the word
>> >> >> > 'always.'
>> >> >>
>> >> >> So its downstream when cold then diverted to atmosphere when it
>> >> >> reaches
>> >> >> norm operating temp, exept under certain conditions? What are those
>> >> >> conditions?
>> >> >
>> >> > Your question was;
>> >> > "How can you pump air into
>> >> > the manifold (when its warmed up) and not give the O2 false
>> >> > info?"
>> >> >
>> >> > I gave you the answer.
>> >> > The rest has already been covered.
>> >>
>> >> No, I just asked what those conditions were. What was covered was when
>> >> warmed up, it goes to the manifold. Then you said not "always". What I
>> >> want
>> >> to know is the "not always" part when its warm.
>> >
>> > Please refrain from misquoting me.
>> > I did not say "not always." I said that Jim and Tom's replies
>> > did not contain the word "always."
>> > If what was covered (by your admission) was when warmed up, what
>> > more needs to be said?
>> >
>> >> When during closed loop does
>> >> the ECM not look at the O2 (when is it injecting air in the manifold
>> >> in
>> >> closed loop) like you said?
>> >
>> > Who said anything about "closed loop?"
>> > Do you understand what "closed loop" means?
>> > If you did, you wouldn't have made that statement.
>> >
>> >> If you don't know just say so, I'm just trying
>> >> to learn about the system here....
>> >
>> > Forget the "system," work on the basics first.
>> > a) closed loop versus open loop
>> > b) cold operation versus warm operation
>> > c) purpose of the oxygen sensor
>>
>> You know what aarcuba, I'm thinking you don't know how it works and your
>> just trying to sound like you do. I know very well the "basics" you
>> listed
>> above. My question was: Its got an O2 sensor in that manifold (or just
>> below
>> it). How can you pump air into the manifold (when its warmed up) and not
>> give the O2 false info? You replied, "By programming the PCM to ignore O2
>> sensor signals under conditions when air is being injected upstream."
>> Again,
>> my question was simple....what are those conditions? Let me give you a
>> few
>> examples so you won't be confused:
>>
>> 1. On decel
>
> It should be obvious that pumping air into the exhaust manifold
> during decel would cause afterburn up to and including the point
> where the muffler is split open.
>
>> 2. At WOT.
>
> O2 is ignored during WOT, so yes, it could be done then.
>
>> 3. At cruise.
>
> If that's what the engineers choose.
>
>> 4. At no time when the vehicle is in closed loop will the air be diverted
>> to
>> the manifold, I was wrong, it diverts it to atmosphere.
>
> By definition, if it's in closed loop the O2 isn't being ignored.
>
>> 5. At no time when the vehicle is in closed loop, I was wrong, it diverts
>> downstream.
>
> By definition, if it's in closed loop the O2 isn't being ignored.
>
>> 6. I have no idea, all I know is the basics.
>
> Read a book then.
>
>> 7. I will come up with a smart ass answer to try and look smart like:
>> When
>> it ignores the O2 it's not *really* in closed loop.
>
> That would be a fact. The system can NOT ignore the O2 -and- be
> in closed loop. If you have a problem with this, then you don't
> understand closed loop, you don't understand the basics.
>
>> Or, you just said
>> "warmed up" not closed loop.
>
> They are two entirely different things, just like an engine can
> be not warmed up and in closed loop.
>
>> 8. I will turn this into an argument about closed loop instead, so people
>> don't know that all I know is the basics.
>
> Feel free.
>
>> I'm thinking the real answer is either #4 and/or 5 AND 6. But you will
>> come
>> up with something like 6, 7, or 8.
>
> Well, if you're smart enough to claim that I don't know how it
> works, why are you asking such basic questions and more
> importantly, why are your questions seasoned with
> misunderstanding?
>
> I think the answer you're looking for is;
> any time there is excess CO or HC in the exhaust that would not
> be scrubbed by the catalytic convertor due to any number of
> factors such as, WOT, a cooled off cat, insufficient oxygen to
> the cat to support oxidation, during a hot restart when fuel
> vapors may be high, etc.

lol Never mind.......please.

rottyguy70@yahoo.com

hey all, seems like some tangental conversation has ensued. i think i
found my answer and just wanted to share.

the newer dynomax direct fit style exhaust system comes with a
pre-capped nipple off the catalytic converter. i believe i can
purchase a universal air tube kit to tie the old style tube/thermactor
to this new style (smaller) nipple. if the weather holds up tomorrow i
will give this approach a shot and report back.

thanks again.

Jim Warman

Welcome to UseNet.... Not often that threads can stay on topic as they occur
on what is possibly one of the purest forms of roundtable discussion
available. Ofen, the sidebars are more interesting and gather much more
information than the original post.


<rottyguy70@yahoo.com> wrote in message
news:1135647370.427112.172200@g14g2000cwa.googlegroups.com...
> hey all, seems like some tangental conversation has ensued. i think i
> found my answer and just wanted to share.
>
> the newer dynomax direct fit style exhaust system comes with a
> pre-capped nipple off the catalytic converter. i believe i can
> purchase a universal air tube kit to tie the old style tube/thermactor
> to this new style (smaller) nipple. if the weather holds up tomorrow i
> will give this approach a shot and report back.
>
> thanks again.
>