help exhaust glowing

jeffcoslacker > wrote in
:

>
> Kevin Bottorff Wrote:
>> If you would bother to check almost every eng still has a air pump.
>> and air passages are intragel with the head, not external. air is
still
>> added post combustion as has been since the adoption of cats.
>> .
>
> Really? As a state liscenced emissions tech since 1991, that's the
> first I've heard of it, outside of the active and passive systems I've
> already described, which are obsolete now.
>
> Where is this pump located? I'll have to go check it out.
>
> Wanna explain how a closed loop feedback system with multiple o2
> sensors can create an accurate reading of o2 levels in combustion gases
> if external air is admitted before sensing? I'm fascinated.
>
> Please quote some sources, because I've been looking since you posted
> this, and can't find a thing about it...
>
>

ok then, explain how they ever did it. They have had O2 sensors since
before FI and were using air pumps then too, and not just to blow into
the cat as some now do.
(not an answer just a question) I am going to recheck some newer ones to
see about the air pump and head air injection thing to be sure. KB

--
Thunder Snake #9
"Protect" your rights or "lose" them.

TeGGeR® Wrote:
>
>
> I once saw this exact thing on an '80s Lada Riva (Russian 4WD). It
> later
> turned out the carb float had sunk and tons of fuel was being dumped
> into
> the engine to the point that the engine eventually stalled and would
> not
> restart.
>
> By the time I got to see it, the cat was glowing literally orange and
> the
> rubber hanger rings were on fire. Good thing there was snow beside the
> road. By throwing snow at the cat, we were able to extinguish the
> fires
> before the vehicle itself went up.
>
> That was a night to remember, let me tell you.
>
>
> --
> TeGGeR®

The Russian cars of the 80s had cats?


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Kevin Bottorff Wrote:
> jeffcoslacker > wrote in
> :
>
> >
> > Kevin Bottorff Wrote:
> >> If you would bother to check almost every eng still has a air pump.
> >> and air passages are intragel with the head, not external. air is
> still
> >> added post combustion as has been since the adoption of cats.
> >> .
> >
> > Really? As a state liscenced emissions tech since 1991, that's the
> > first I've heard of it, outside of the active and passive systems
> I've
> > already described, which are obsolete now.
> >
> > Where is this pump located? I'll have to go check it out.
> >
> > Wanna explain how a closed loop feedback system with multiple o2
> > sensors can create an accurate reading of o2 levels in combustion
> gases
> > if external air is admitted before sensing? I'm fascinated.
> >
> > Please quote some sources, because I've been looking since you posted
> > this, and can't find a thing about it...
> >
> >
>
> ok then, explain how they ever did it. They have had O2 sensors since
> before FI and were using air pumps then too, and not just to blow into
> the cat as some now do.
> (not an answer just a question) I am going to recheck some newer ones
> to
> see about the air pump and head air injection thing to be sure. KB
>
> --
> Thunder Snake #9
> "Protect" your rights or "lose" them.

Early O2 sensor systems used air pumped into the forward portion of the
cat, that and the O2 sensor resided upstream of that point, so it was
monitoring pre-air injection gases. As soon as pre and post cat sensor
setups and full closed loop became the rule, air injection had to be
abandoned...not neccessary with the fine control of mixture that dual
sensors and faster processing offered...

some real early ones had an O2 sensor right up next to the engine in
the manifold, with air injected slightly downstream, those manifolds
has a big "plenum" shape to them...the sensor still monitored mixture
ahead of the incoming air...

Carbed engines with O2 sensors were very crude feedback systems, made
to try to maintain an "overall" quality of mixture, rather than moment
by moment control...


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In article >,
jeffcoslacker > wrote:

> Kevin Bottorff Wrote:
> > jeffcoslacker > wrote in
> > :
> >
> > >
> > > Kevin Bottorff Wrote:
> > >> If you would bother to check almost every eng still has a air pump.
> > >> and air passages are intragel with the head, not external. air is
> > still
> > >> added post combustion as has been since the adoption of cats.
> > >> .
> > >
> > > Really? As a state liscenced emissions tech since 1991, that's the
> > > first I've heard of it, outside of the active and passive systems
> > I've
> > > already described, which are obsolete now.
> > >
> > > Where is this pump located? I'll have to go check it out.
> > >
> > > Wanna explain how a closed loop feedback system with multiple o2
> > > sensors can create an accurate reading of o2 levels in combustion
> > gases
> > > if external air is admitted before sensing? I'm fascinated.
> > >
> > > Please quote some sources, because I've been looking since you posted
> > > this, and can't find a thing about it...
> > >
> > >
> >
> > ok then, explain how they ever did it. They have had O2 sensors since
> > before FI and were using air pumps then too, and not just to blow into
> > the cat as some now do.
> > (not an answer just a question) I am going to recheck some newer ones
> > to
> > see about the air pump and head air injection thing to be sure. KB
> >
> > --
> > Thunder Snake #9
> > "Protect" your rights or "lose" them.
>
> Early O2 sensor systems used air pumped into the forward portion of the
> cat,

That would render the NOx bed inoperative.

> that and the O2 sensor resided upstream of that point, so it was
> monitoring pre-air injection gases. As soon as pre and post cat sensor
> setups and full closed loop became the rule, air injection had to be
> abandoned...not neccessary with the fine control of mixture that dual
> sensors and faster processing offered...

Mid 90s GM OBD2 systems used an electric air pump that pumped
into the exhaust manifolds. An example would be a 1996 Pontiac
Grand Prix with a 3400 engine. Worked on a late 90s Audi a while
back that had a secondary electric air pump also.

> some real early ones had an O2 sensor right up next to the engine in
> the manifold, with air injected slightly downstream, those manifolds
> has a big "plenum" shape to them...the sensor still monitored mixture
> ahead of the incoming air...
>
> Carbed engines with O2 sensors were very crude feedback systems, made
> to try to maintain an "overall" quality of mixture, rather than moment
> by moment control...

The original GM feedback system introduced in 1980 was called CCCC
(Computer Controlled Catalytic Convertor) it controlled whether
the air pump switched upstream to the manifolds, downstream to
the cat or dumped to atmosphere. The CCCC moniker was changed in
1981 to CCC Computer Command Control, it was a bit more refined,
a bit more powerful but still controlled whether the air pump
switched upstream, downstream or atmospheric.
On cold start open loop, it's no special trick to pump air into
an exhaust manifold, on warm engine closed loop, it's no special
trick to pump air downstream to an oxidizing bed of a catalytic
convertor or to atmosphere, or in the case of an electric air
pump, simply shut it off.

aarcuda69062 Wrote:
>
> That would render the NOx bed inoperative.
>
> Early 2 way cats didn't deal with NOx...
>
> Mid 90s GM OBD2 systems used an electric air pump that pumped
> into the exhaust manifolds. An example would be a 1996 Pontiac
> Grand Prix with a 3400 engine. Worked on a late 90s Audi a while
> back that had a secondary electric air pump also.

A 1996 Pontiac would still be OBD I...



>
> The original GM feedback system introduced in 1980 was called CCCC
> (Computer Controlled Catalytic Convertor) it controlled whether
> the air pump switched upstream to the manifolds, downstream to
> the cat or dumped to atmosphere. The CCCC moniker was changed in
> 1981 to CCC Computer Command Control, it was a bit more refined,
> a bit more powerful but still controlled whether the air pump
> switched upstream, downstream or atmospheric.
> On cold start open loop, it's no special trick to pump air into
> an exhaust manifold, on warm engine closed loop, it's no special
> trick to pump air downstream to an oxidizing bed of a catalytic
> convertor or to atmosphere, or in the case of an electric air
> pump, simply shut it off.

These I never had to have any real reason to understand, was not doing
emissions control work when they were still rolling in numbers, so
thanks for that, it was interesting.


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Kevin Bottorff wrote:

> jeffcoslacker > wrote in
> :
>
>
>>Kevin Bottorff Wrote:
>>
>>>If you would bother to check almost every eng still has a air pump.
>>>and air passages are intragel with the head, not external. air is
>
> still
>
>>>added post combustion as has been since the adoption of cats.
>>>.
>>
>>Really? As a state liscenced emissions tech since 1991, that's the
>>first I've heard of it, outside of the active and passive systems I've
>>already described, which are obsolete now.
>>
>>Where is this pump located? I'll have to go check it out.
>>
>>Wanna explain how a closed loop feedback system with multiple o2
>>sensors can create an accurate reading of o2 levels in combustion gases
>>if external air is admitted before sensing? I'm fascinated.

Ever heard of "upstream sensor" and "downstream sensor?"

In article >,
jeffcoslacker > wrote:

> aarcuda69062 Wrote:
> >
> > That would render the NOx bed inoperative.
> >
> > Early 2 way cats didn't deal with NOx...

Well, yeah, by definition, a two way cat wouldn't be reducing NOx.
Bulldozers don't float either.
Define "early." You claim having a smog license since 1991.

> > Mid 90s GM OBD2 systems used an electric air pump that pumped
> > into the exhaust manifolds. An example would be a 1996 Pontiac
> > Grand Prix with a 3400 engine. Worked on a late 90s Audi a while
> > back that had a secondary electric air pump also.
>
> A 1996 Pontiac would still be OBD I...

It most certainly would not.
Hell there were 'pull ahead' 94s and 95s that were OBD2.

>
>
> >
> > The original GM feedback system introduced in 1980 was called CCCC
> > (Computer Controlled Catalytic Convertor) it controlled whether
> > the air pump switched upstream to the manifolds, downstream to
> > the cat or dumped to atmosphere. The CCCC moniker was changed in
> > 1981 to CCC Computer Command Control, it was a bit more refined,
> > a bit more powerful but still controlled whether the air pump
> > switched upstream, downstream or atmospheric.
> > On cold start open loop, it's no special trick to pump air into
> > an exhaust manifold, on warm engine closed loop, it's no special
> > trick to pump air downstream to an oxidizing bed of a catalytic
> > convertor or to atmosphere, or in the case of an electric air
> > pump, simply shut it off.
>
> These I never had to have any real reason to understand, was not doing
> emissions control work when they were still rolling in numbers, so
> thanks for that, it was interesting.

Glad to help.

Steve Wrote:
> Kevin Bottorff wrote:
>
> > jeffcoslacker > wrote in
> > :
> >
> >
> >>Kevin Bottorff Wrote:
> >>
> >>>If you would bother to check almost every eng still has a air pump.
> >>>and air passages are intragel with the head, not external. air is
> >
> > still
> >
> >>>added post combustion as has been since the adoption of cats.
> >>>.
> >>
> >>Really? As a state liscenced emissions tech since 1991, that's the
> >>first I've heard of it, outside of the active and passive systems
> I've
> >>already described, which are obsolete now.
> >>
> >>Where is this pump located? I'll have to go check it out.
> >>
> >>Wanna explain how a closed loop feedback system with multiple o2
> >>sensors can create an accurate reading of o2 levels in combustion
> gases
> >>if external air is admitted before sensing? I'm fascinated.
>
> Ever heard of "upstream sensor" and "downstream sensor?"

You misread everything I post, and then throw it back at me without
comprehension as if you are making a point, when you are saying exactly
what I just said....What did you think I meant by multiple sensors?


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aarcuda69062 Wrote:
> In article >,
> jeffcoslacker > wrote:
>
> > aarcuda69062 Wrote:
> > >
> > > That would render the NOx bed inoperative.
> > >
> > > Early 2 way cats didn't deal with NOx...
>
> Well, yeah, by definition, a two way cat wouldn't be reducing NOx.
> Bulldozers don't float either.
> Define "early." You claim having a smog license since 1991.
>
> Glad to help.

I know there were some that didn't fully incoporarte all the OBDII
equipment but could be scanned as OBDII, they were called OBD 1.5 or
something like that, never ran across one *with a reason for me to note
that aspect of it anyway)

I meant real early. Back in the dark ages. Smog pumps. 2 way cats. Big
block motors that couldn't pass a 1.5L Toyota Tercel with a rolling
start...when did diagnostic connectors and check engine lights start
showing up on everything, about 1981? That's the age I'm talking.


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In article >,
jeffcoslacker > wrote:

> about 1981? That's the age I'm talking.

In 198O and later, there certainly was a preponderance of three
way NOx reducing cats. That was the whole point of having the
PCM control where the air pump introduced the O2 (either upstream
into the exhaust manifold or downstream into the second bed of
the cat).
On cold start with a rich mixture, there isn't much NOx
production but there is excess CO and HC, so the air pump pumped
O2 into the exhaust manifolds to aid oxidization of CO and HC
before it could overload the cat.
On warm running with the PCM in closed loop, the air pump was
switched to downstream where it pumped O2 to the rear oxidizing
bed for final clean up of CO and HC, the NOx reducing bed was
forward located in the cat ahead of the air pump inlet because O2
hinders the reduction of NOx.
At some point into closed loop, the air pump -might- have been
switched to dump to atmosphere if the NOx bed was reducing
sufficiently to supply the rear oxidizing bed with the O2 it
needed to work properly.
Nowdays, with really efficient NOx reduction, there is enough O2
split off of the NOx molecules to feed the rear oxidizing bed the
O2 supply that it needs, thus making air pumps somewhat less
necessary but not totally extinct.