Honda Car Forum

On 7 Jun 2004 12:41:39 GMT, "Tegger®"
<teggeratistopdotcom@changetheobvious.invalid> wrote:

>"Caroline" <caroline10027remove@earthlink.net> spake unto the masses in
>news:1aSwc.4712$uX2.630@newsread2.news.pas.earthl ink.net:
>
>> If you're not so concerned, and have no symptoms of a malfunctioning
>> PCV valve (e.g. reduced fuel mileage; oil seals leaking oil),
>
>
>
>Those are not symptoms of a plugged PCV valve. Stop misleading people.

We've been through all this before - I guess it just got left dangling.:-)

I know (think ?) we agreed that the PCV is a metered air leak. How can it
not affect engine efficiency and therefore fuel mileage? BTW I'm quite
sure that a PCV can fail in more ways than getting plugged up - e.g. the
spring can get gunked up and bind. The PCV lives an environment which is
not kind to metal or even plastics.

I'm quite sure that the reason the rubber plug at the end of the exhaust
camshaft of an Integra, next to the distributor, gets pushed out is because
of crankcase pressure increase. It seems to happen more in Winter when the
PCV can get frozen up.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

> I'm quite sure that the reason the rubber plug at the end of the exhaust
> camshaft of an Integra, next to the distributor, gets pushed out is because
> of crankcase pressure increase. It seems to happen more in Winter when the
> PCV can get frozen up.

if you wanna be safe and not necessarily "ecologically correct", im sure
you could get a second oil cap and put some kind of foam filter or valve
tapped into it for good measure

swap it back for the biennual smog check tho!

George Macdonald <fammacd=!SPAM^nothanks@tellurian.com> spake unto the
masses in newsufac0t3919lbv113gr55d8iru2nuv4u7v@4ax.com:

>
> I know (think ?) we agreed that the PCV is a metered air leak. How
> can it not affect engine efficiency and therefore fuel mileage?



Because the air and blowby is coming from, and going to, the SAME PLACE AT
ALL TIMES.

Go take a good hard look at your own PCV system. See where the crankcase
takes in air. See where the PCV valve dumps its air. Notice that BOTH are
located in the INTAKE tract, mere inches from each other?

There is NO "air leak".

The valve does NOT introduce new air into the system.

It simply meters the existing air so as to ensure that there is POSITIVE
flow through the crankcase, resulting in a constant changeover of the air
in the crankcase, with any blowby gases routed back through the combustion
chamber again.

A blocked PCV Valve but a free breather will cause the gases to cavitate
inside the crankcase. Since the breather will be under slight depression
from the intake tract, pressure will be higher in the crankcase than the
intake, so excess gases will get pushed into the intake and recycled
through the combustion chamber again, just as if they went through the PCV
properly, but there will be be no positive flow.

The main purpose of the PCV valve is to ensure that one end of the breather
system always has a lower pressure than the other, so that one end will
always be an intake, and one will always be an outlet. That is why it has a
variable orifice.



> BTW
> I'm quite sure that a PCV can fail in more ways than getting plugged
> up - e.g. the spring can get gunked up and bind.



How is this different from being "plugged up"?

The PCV plunger is surrounded by the spring. The metered orifice is the
SPACE around the coils of the spring. If the spring gets gunked up, then
the orifice is reduced, becuase the orifice IS around the spring.



> The PCV lives an
> environment which is not kind to metal or even plastics.



And it is made of metal and oil-compatible plastics. You don't think they
would think of doing that?



>
> I'm quite sure that the reason the rubber plug at the end of the
> exhaust camshaft of an Integra, next to the distributor, gets pushed
> out is because of crankcase pressure increase. It seems to happen
> more in Winter when the PCV can get frozen up.



It happens because the rubber gets old and has reduced holding power,
especially when cold. It is only really clamped in place by the two little
ridges on it anyway. This explained to me by my Japanese mechanic. I
replaced my leaky old one a few years ago. It has not leaked since.

In order for pressure to build to the point where it could possibly "push
the plug out", BOTH the PCV AND the breather MUST be blocked.


--
TeGGeR®

The Unofficial Honda FAQ
http://www3.telus.net/public/johnings/faq.html

How to find anything on the Internet or in Usenet Groups:
www.google.com
www.groups.google.com

y_p_w@hotmail.com (y_p_w) spake unto the masses in
news:591da479.0406071533.2642c43a@posting.google.c om:

> "Tegger®" <teggeratistopdotcom@changetheobvious.invalid> wrote in
>>
>> A plugged PCV valve does not affect gas mileage. End of story.
>
> Dude - I read it and saw who the source was:
>
> "A malfunctioning P.C.V. may result in a hard starting engine, surge
> at cruise, and hesitation on acceleration. P.C.V. malfunctions lower
> fuel economy since it is a vacuum device."



The PCV *SYSTEM*, or the PCV *VALVE*?

Your quote does not say.

If the PCV *system* is malfunctioning, then definitely those symptoms may
be caused. Such as if the breather hose is cracked or disconnected. Such as
if the PCV valve grommet has perished and is letting air in around the
valve stem.



I am starting to suspect that posters here are thinking that the "system"
consists of the valve alone.


--
TeGGeR®

The Unofficial Honda FAQ
http://www3.telus.net/public/johnings/faq.html

How to find anything on the Internet or in Usenet Groups:
www.google.com
www.groups.google.com

"Caroline" <caroline10027remove@earthlink.net> spake unto the masses in
news:Kt3xc.5694$uX2.5381@newsread2.news.pas.earthl ink.net:

> Tegger wrote:
> snip non-rebuttal
>> It is necessary that BOTH the crankcase breather AND the PCV valve
>> get plugged.
>
> We've been over this. If the PCV valve plugs, that's one less path for
> the crankcase gases to escape. Steady state crankcase pressure thus
> will be higher with a plugged PCV valve. This places more pressure on
> various oil seals. Thus they may fail sooner.



Wrong. Totally incorrect understanding of the PCV system.

And even if plugged, a PCV valve will NOT affect mileage.


--
TeGGeR®

The Unofficial Honda FAQ
http://www3.telus.net/public/johnings/faq.html

How to find anything on the Internet or in Usenet Groups:
www.google.com
www.groups.google.com

George Macdonald <fammacd=!SPAM^nothanks@tellurian.com> spake unto the
masses in newsufac0t3919lbv113gr55d8iru2nuv4u7v@4ax.com:

> I know (think ?) we agreed that the PCV is a metered air leak. How
> can it not affect engine efficiency and therefore fuel mileage?



I just asked my mechanic, who has specialized in Japanese cars for 40 years
and has run his own shop for the last twenty (no, from 1980, so 24 years).
He does everything up to and including rebuilding engines and
troubleshooting electronics problems.

He says a plugged PCV valve will definitely NOT affect gas mileage. End of
story. The computer would compensate for any metering incorrectness
resulting therefrom.

That makes three *actual working mechanics*, all with many years of
experience, who have told me that a plugged PCV valve WILL NOT affect gas
mileage.


Caroline's many instances of Google results are WRONG. Plain and simple
WRONG. "Internet legends" is what they are. WRONG. Misleading.




--
TeGGeR®

The Unofficial Honda FAQ
http://www3.telus.net/public/johnings/faq.html

How to find anything on the Internet or in Usenet Groups:
www.google.com
www.groups.google.com

What year was this written? Years ago, Honda never even
bothered with PCV valves because minor dirt in PCV valves
would cause major problems with air mixture in carburetion.
In fact I am surprised Honda has even gone to PCV valves.
1980s Hondas never used PCV valves. Hondas has a superior
alternative design. But then with fuel injection, changes in
air bypass do not adversely affect air mixture. Throttle is
just another source of air leakage in a fuel injected system.

IOW that text is probably correct when PCV valves were
connected to carburetors. It does not apply to fuel injected
system.

Alan - don't worry about the PCV valve. The valve does
exactly as you have described. If a valve is so clogged as to
cause crankcase ventilation problems, then the engine has far
more serious problems than a clogged PCV valve.

y_p_w wrote:
> Dude - I read it and saw who the source was:
>
> "A malfunctioning P.C.V. may result in a hard starting engine, surge
> at cruise, and hesitation on acceleration. P.C.V. malfunctions lower
> fuel economy since it is a vacuum device."
>
> and the source (at least the guy who cross-checked the info).....
>
> CURRICULUM WRITER & PROGRAM CONSULTANT
> Joseph H. Pons, III.
> Associate Professor
> Industrial Technology
> University of Southwestern Louisiana
>
> He seems to have either retired or moved on from Southeastern
> Louisiana University. I did find his CV in a cached archive:
>
> "Joe Pons has 23 years university teaching. Prior to joining the
> ITEC faculty, he worked for Ford Motor Co. as a zone technical
> manager and district parts and service management consultant. He
> has also taught two years at a secondary school and one year at a
> post-secondary technical institute. Technical interests lie in
> mechanical and fluid power technologies, and he serves as the
> coordinator for these courses. Upper level courses include these
> aspects of automation and robotics.
>
> He earned a BS degree in Industrial Arts Education from louisiana
> and a MS from LSU in Adult Vocational and Technical Education with
> a minor in Management. While at Ford, prior to receiving his MS, he
> acquired extensive management training."

In article <oufac0t3919lbv113gr55d8iru2nuv4u7v@4ax.com>,
George Macdonald <fammacd=!SPAM^nothanks@tellurian.com> wrote:

> I know (think ?) we agreed that the PCV is a metered air leak. How can it
> not affect engine efficiency and therefore fuel mileage? BTW I'm quite
> sure that a PCV can fail in more ways than getting plugged up - e.g. the
> spring can get gunked up and bind.

Yes, mine failed "open" (94 del Sol Si). When I pinched the hose
at idle, there was no click and the idle changed. If it had been
plugged, there would also have been no click, but the idle would not
have changed.

On Tue, 08 Jun 2004 10:28:24 -0400, w_tom <w_tom1@hotmail.com> wrote:

> What year was this written? Years ago, Honda never even
>bothered with PCV valves because minor dirt in PCV valves
>would cause major problems with air mixture in carburetion.
>In fact I am surprised Honda has even gone to PCV valves.
>1980s Hondas never used PCV valves. Hondas has a superior
>alternative design. But then with fuel injection, changes in
>air bypass do not adversely affect air mixture. Throttle is
>just another source of air leakage in a fuel injected system.
>
> IOW that text is probably correct when PCV valves were
>connected to carburetors. It does not apply to fuel injected
>system.

Of course it does. A fuel injection system has to know the mass of air
being sucked into the combustion chambers to meter the fuel accurately.
Compensation has to be built into the ECU rules for the metered air leak of
a PCV valve.

> Alan - don't worry about the PCV valve. The valve does
>exactly as you have described. If a valve is so clogged as to
>cause crankcase ventilation problems, then the engine has far
>more serious problems than a clogged PCV valve.

There are lots of ways things can go wrong and several variables. Have
ever taken a PCV valve off and looked down the tube coming from the
breather box? Try it in Winter and you'll see a coating or clog of
emulsified oil down there depending on whether the valve is functioning
properly.

>y_p_w wrote:
>> Dude - I read it and saw who the source was:
>>
>> "A malfunctioning P.C.V. may result in a hard starting engine, surge
>> at cruise, and hesitation on acceleration. P.C.V. malfunctions lower
>> fuel economy since it is a vacuum device."
>>
>> and the source (at least the guy who cross-checked the info).....
>>
>> CURRICULUM WRITER & PROGRAM CONSULTANT
>> Joseph H. Pons, III.
>> Associate Professor
>> Industrial Technology
>> University of Southwestern Louisiana
>>
>> He seems to have either retired or moved on from Southeastern
>> Louisiana University. I did find his CV in a cached archive:
>>
>> "Joe Pons has 23 years university teaching. Prior to joining the
>> ITEC faculty, he worked for Ford Motor Co. as a zone technical
>> manager and district parts and service management consultant. He
>> has also taught two years at a secondary school and one year at a
>> post-secondary technical institute. Technical interests lie in
>> mechanical and fluid power technologies, and he serves as the
>> coordinator for these courses. Upper level courses include these
>> aspects of automation and robotics.
>>
>> He earned a BS degree in Industrial Arts Education from louisiana
>> and a MS from LSU in Adult Vocational and Technical Education with
>> a minor in Management. While at Ford, prior to receiving his MS, he
>> acquired extensive management training."

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

On 8 Jun 2004 13:56:04 GMT, "Tegger®"
<teggeratistopdotcom@changetheobvious.invalid> wrote:

>George Macdonald <fammacd=!SPAM^nothanks@tellurian.com> spake unto the
>masses in newsufac0t3919lbv113gr55d8iru2nuv4u7v@4ax.com:
>
>> I know (think ?) we agreed that the PCV is a metered air leak. How
>> can it not affect engine efficiency and therefore fuel mileage?
>
>
>
>I just asked my mechanic, who has specialized in Japanese cars for 40 years
>and has run his own shop for the last twenty (no, from 1980, so 24 years).
>He does everything up to and including rebuilding engines and
>troubleshooting electronics problems.

Look I don't really care what your mechanic says. I've been told enough
guff by mechanics over the years to fill an encyclopaedia.

>He says a plugged PCV valve will definitely NOT affect gas mileage. End of
>story. The computer would compensate for any metering incorrectness
>resulting therefrom.

The computer hasn't measured the mass of leaked air - it doesn't know about
it other than some fixed compensation curve built into the engine parameter
profile... based on a properly functioning PCV valve.

>That makes three *actual working mechanics*, all with many years of
>experience, who have told me that a plugged PCV valve WILL NOT affect gas
>mileage.
>
>
>Caroline's many instances of Google results are WRONG. Plain and simple
>WRONG. "Internet legends" is what they are. WRONG. Misleading.

So your mechanics are right and the auto mfrs and engine designers are all
wrong.<shrug>

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??