Very OT: PCV valves in cars, without springs?

[Joerg]

Couldn't find a decent car group but I know there are some folks here
who know automotive well.

In preparation for a smog check (was marginal for HC at 15mph last time)
I also swapped out the PCV valve for crankcase venting. 1996 Toyota
Corolla. The old one rattled when shaken. I thought the spring had
broken. The new one is a MicroGuard PCV385 and ... rattles just like the
old one. No spring action can be felt on the plunger.

Is this normal? How can they work with the plunger just sloshing around
in there?

I did notice that the new one has more travel in the plunger so maybe
the old one is a bit dirty inside.

--
Regards, Joerg

http://www.analogconsultants.com/

[Lasse Langwadt Christensen]

Den onsdag den 17. januar 2018 kl. 00.51.58 UTC+1 skrev Joerg:
> Couldn't find a decent car group but I know there are some folks here
> who know automotive well.
>
> In preparation for a smog check (was marginal for HC at 15mph last time)
> I also swapped out the PCV valve for crankcase venting. 1996 Toyota
> Corolla. The old one rattled when shaken. I thought the spring had
> broken. The new one is a MicroGuard PCV385 and ... rattles just like the
> old one. No spring action can be felt on the plunger.
>
> Is this normal? How can they work with the plunger just sloshing around
> in there?

they rely on gravity or the spring is very weak? afaict from googling
rattling is normal

[Jim Thompson]

On Tue, 16 Jan 2018 15:51:57 -0800, Joerg <ne...@analogconsultants.com>
wrote:

Look for a vent blocked by gunk. (Other side of the block if it's a
V-8... I don't know about weenie engines ;-)

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

It's what you learn, after you know it all, that counts.

[Martin Riddle]

On Tue, 16 Jan 2018 15:51:57 -0800, Joerg <ne...@analogconsultants.com>
wrote:

My 95 Chevy PVC is the same no spring. You want flow into the intake
manifold, not the other way around.

Cheers

[George Herold]

Try rec.crafts.metalworking There's even a higher political
'noise' content than here. But still lotsa smart gear heads.

George H.

[Carl Ijames]

On Tuesday, January 16, 2018 at 6:51:58 PM UTC-5, Joerg wrote:
> Couldn't find a decent car group but I know there are some folks here
> who know automotive well.
>
> In preparation for a smog check (was marginal for HC at 15mph last time)
> I also swapped out the PCV valve for crankcase venting. 1996 Toyota
> Corolla. The old one rattled when shaken. I thought the spring had
> broken. The new one is a MicroGuard PCV385 and ... rattles just like the
> old one. No spring action can be felt on the plunger.
>
> Is this normal? How can they work with the plunger just sloshing around
> in there?
>
> I did notice that the new one has more travel in the plunger so maybe
> the old one is a bit dirty inside.
>
> --
> Regards, Joerg
>
> http://www.analogconsultants.com/

According to wikipedia there is a very weak spring inside:
https://en.wikipedia.org/wiki/Crankcase_ventilation_system Also explains
the valve action at idle, cruise, and wot if you really want to understand
the whole system.

--
Regards,
Carl Ijames

[Joerg]

You can hold it upside down and the plunger falls to the downward end.
There really is no spring action.

[Joerg]

When I blow through it air passes both ways but with different
resistance. For the old PCV valve as well as the new one. I have just
never seen anything like that.

[Joerg]

I know roughly how it works and that there usually is a spring inside.
However, in the ones for the 96 Corolla there isn't, neither the old not
new one. Different mfgs and it is highly unlikely that the new and the
old one are both broken. It's weird.

[Joerg]

Oh man, that seems like a really rogue group :-)

Didn't see any car-related threads in it.

[olds...@tubes.com]

On Tue, 16 Jan 2018 15:51:57 -0800, Joerg <ne...@analogconsultants.com>
wrote:

As others have said, they are supposed to rattle. On my old 80's 90's
cars, I would replace them at every tuneup. They were not real costly
back then. But a mechanic told me to stop wasting my money. He took them
and soaked them in a some carb cleaner. Shook them a few times during
the soaking. (Or sprayed pressurized carb cleaner into them). Then blow
a little compressed air thru them and they were good as new.

Always make sure the grommet they push into is good and the hose
connected to them is also good, and clean on the inside. (more carb
cleaner and comp. air to clean hose if it's still good).

For auto newsgroups, look to alt.autos.******* and alt.trucks.*******
Not much activity these days, but still some.

[George Herold]

I think in general they will be happy to talk about car/ vehicle
problems/ questions. I've gotten good advice there.

And of course any real threads are quickly buried under the barrage
of political crud.

George H.

[jurb...@gmail.com]

>"You can hold it upside down and the plunger falls to the downward end.
There really is no spring action. "

That is normal for most cars. The weight inside is the calibration. If it gets dirty the flow goes down and the crankcase fumes get spewed instead of going into the intake manifold to get burned.

If you have an engine with high blowby, they make a high flow PCV valve that usually will help.

To test for blowby, remove the oil filler cap and put a piece of paper on it, you should feel vacuum, NOT PRESSURE. Pressure means the rings are worn or there is an internal engine fault such as a slightly leaky gasket or something of that nature. That causes the pressure in the crankcase to exceed the vacuum the PCV allows. (volume actually)

Generally, if you are high on HC but not CO, the mixture is on the lean side and you're getting a lean misfire. If both HC and CO are high you usually have an ignition problem or an internal engine fault.

For it to be on the lean side and not throw a check engine light there is usually a vacuum leak right near the intake valve of one (or more) cylinder(s). That is the only way the O2 sensor can be satisfied with a lean mixture. A leaky EGR valve can also cause it but those are usually easy to fix. Usually a piece of dirt gets caught in there and won't allow the valve to fully close, which is very similar to a regular vacuum leak. One engine we had was so gunked up from never being punched that when you did hit the gas hard there was another piece of dirt and it would run funny. Eventually we went to a head shop and bought a pipe screen and that fixed it for good. If you have alot of miles you might have to do that.

To reiterate in case you missed the thread - to check for a vacuum leak :

Disconnect the IAC (idle air control). Spray either ether or propane at suspected areas and watch for the RPM to rise.

Disconnecting the IAC keeps the computer out of the idle speed control. The control may be so precise you can't tell because it is compensated so fast.

This will set a code so you will need a scanner to reset it in most cars. Most people know at least one person who has such a scanner. Buy them a few beers and let them plug in and push the button. Most of them like their toy and don't get enough chances to use it.

[Bill Martin]

One thing that's easy & may help: make sure you have "new" oil, as in
just changed, before you submit to the posterior probing. Possible a
grade thicker than spec if you are worried. The Japanese engines tend to
have soft rings, I see a lot of hi-milers running around here (near the
Mx border), some of them really smokey, but running just fine. Don't
know how they get away with that...

[Joerg]

On 2018-01-17 15:53, jurb...@gmail.com wrote:
>> "You can hold it upside down and the plunger falls to the downward
>> end.
> There really is no spring action. "
>
> That is normal for most cars. The weight inside is the calibration.

Thanks, I didn't know that was possible but it seems it is.

> If it gets dirty the flow goes down and the crankcase fumes get
> spewed instead of going into the intake manifold to get burned.
>

Where'd they get spewed to? I also always wondered what could possibly
fume with oil other than miniscule amounts of gas that might seep past
the rings on old engines.

In the olden days that was all simpler. My 16-horse Citroen had a rubber
"fart device" to let go of any crank case flatulence.

> If you have an engine with high blowby, they make a high flow PCV
> valve that usually will help.
>

It is 21 years old but only around 50k miles.

> To test for blowby, remove the oil filler cap and put a piece of
> paper on it, you should feel vacuum, NOT PRESSURE. Pressure means the
> rings are worn or there is an internal engine fault such as a
> slightly leaky gasket or something of that nature. That causes the
> pressure in the crankcase to exceed the vacuum the PCV allows.
> (volume actually)
>
> Generally, if you are high on HC but not CO, the mixture is on the
> lean side and you're getting a lean misfire. If both HC and CO are
> high you usually have an ignition problem or an internal engine
> fault.
>

I read about misfires but the spark plugs are clean and the engine runs
very smoothly. It also never burns any oil.

> For it to be on the lean side and not throw a check engine light
> there is usually a vacuum leak right near the intake valve of one (or
> more) cylinder(s). That is the only way the O2 sensor can be
> satisfied with a lean mixture. A leaky EGR valve can also cause it
> but those are usually easy to fix. Usually a piece of dirt gets
> caught in there and won't allow the valve to fully close, which is
> very similar to a regular vacuum leak. One engine we had was so
> gunked up from never being punched that when you did hit the gas hard
> there was another piece of dirt and it would run funny. Eventually we
> went to a head shop and bought a pipe screen and that fixed it for
> good. If you have alot of miles you might have to do that.
>
> To reiterate in case you missed the thread - to check for a vacuum
> leak :
>
> Disconnect the IAC (idle air control). Spray either ether or propane
> at suspected areas and watch for the RPM to rise.
>
> Disconnecting the IAC keeps the computer out of the idle speed
> control. The control may be so precise you can't tell because it is
> compensated so fast.
>
> This will set a code so you will need a scanner to reset it in most
> cars. Most people know at least one person who has such a scanner.
> Buy them a few beers and let them plug in and push the button. Most
> of them like their toy and don't get enough chances to use it.
>

I'll let the shop handle that if it fails HC at 15mph. Got too much work
right now. A client just threw me three board designs.

The weird thing is that is passes HC at 25mph with great margin, as well
as everything else.

[Joerg]

On 2018-01-17 21:33, Bill Martin wrote:
> On 01/16/2018 03:51 PM, Joerg wrote:
>> Couldn't find a decent car group but I know there are some folks here
>> who know automotive well.
>>
>> In preparation for a smog check (was marginal for HC at 15mph last
>> time) I also swapped out the PCV valve for crankcase venting. 1996
>> Toyota Corolla. The old one rattled when shaken. I thought the spring
>> had broken. The new one is a MicroGuard PCV385 and ... rattles just
>> like the old one. No spring action can be felt on the plunger.
>>
>> Is this normal? How can they work with the plunger just sloshing
>> around in there?
>>
>> I did notice that the new one has more travel in the plunger so maybe
>> the old one is a bit dirty inside.
>>
> One thing that's easy & may help: make sure you have "new" oil, as in
> just changed, before you submit to the posterior probing.

That I will do anyhow. Got the new filter waiting here on the table.


> ... Possible a

> grade thicker than spec if you are worried. The Japanese engines tend to
> have soft rings, I see a lot of hi-milers running around here (near the
> Mx border), some of them really smokey, but running just fine. Don't
> know how they get away with that...

I use 5W30 which is quite thin but cars start easier in winter and my
wife mostly drives short distances where thinner opil is better. Still
our cars never consume any oil. I change every 3k miles at the lastest
or before smog wichever comes first. I never have to add oil inbetween.

The engine is old (21 years) but low mileage (around 50k).

[Jim Thompson]

On Fri, 19 Jan 2018 07:32:52 -0800, Joerg <ne...@analogconsultants.com>
wrote:

[snip]

>
>The weird thing is that is passes HC at 25mph with great margin, as well
>as everything else.

That's the clue that it is the old PCV... flow restriction.

[Joerg]

On 2018-01-19 08:52, Jim Thompson wrote:
> On Fri, 19 Jan 2018 07:32:52 -0800, Joerg <ne...@analogconsultants.com>
> wrote:
>
> [snip]
>>
>> The weird thing is that is passes HC at 25mph with great margin, as well
>> as everything else.
>
> That's the clue that it is the old PCV... flow restriction.
>

I am sure hoping so. Last time it passed with 61ppm out of 61 allowed.
Whew. Since those things do not tend to become better with time by
themselves I am also going on a couple of long rides with Lucas cleaner
added to the tank and giving it a fresh oil & filter change right before
the test.

Strange thing is I did not notice any restrictions in the plunger
movement in the old PCV valve versus the new one. Also, at lower power
the PCV valve is supposed to reduce flow and not increase it. It is
supposed to open at high power, see middle of page:

https://24hourmobilemechanics.com/pcv-valve-related-symptoms-problems/

One of the issues with my wife's car is that it is used almost
exclusively for 2-3 mile trips. Grocery, church, local nursing home
visits. The cat and engine never really warm up except for the few times
I use the car.

[Jim Thompson]

On Fri, 19 Jan 2018 09:21:06 -0800, Joerg <ne...@analogconsultants.com>
wrote:

We're more "boony"... 5 miles to the _closest_ grocery ;-)

[Joerg]

My brewing supply store is 15mi away. When I run out of something and
people find out I go there by bicycle the usual reaction is "WHAT?". To
make it a good exercise it's up and down and on the way back a net
1200ft altitude difference has to be recouped. Same when I need
electrical stuff because the big stores are all down there in the flatlands.

[Mike Perkins]

I would say that's all a very good excuse for an Italian tune-up!

--
Mike Perkins
Video Solutions Ltd
www.videosolutions.ltd.uk

[Joerg]

That is my plan except we have that dreaded 65mph speed limit in the US.
In Germany an hour on the autobahn pedal-to-the-metal would be easy to
do (cars there are usually full-throttle proof). On a Sunday afternoon
when all the others are sitting in front of their TV watching soccer.

We've go tough hills around here but in the end you always have to come
back down and that's where everything cools way down.

[Joerg]

Some feedback: Installed a new PCV valve, gave it the "Italian tune-up",
fresh oil and filter right before the test, got it nice and hot right
before. It passed HC with flying colors but ... failed NOX at 15mph
while passing with huge margin at 25mph. I ran out of time due to a job
so I asked the shop to diagnose and clean whatever may be clogged. They
found some dirty EGR paths and a gunky EGR sensor filter. They cleaned
all that and it passed everything with huge margins. Pretty good for a
21 year old car.

[Jim Thompson]

On Fri, 19 Jan 2018 13:00:51 -0800, Joerg <ne...@analogconsultants.com>
wrote:

>On 2018-01-19 12:38, Mike Perkins wrote:
>> On 19/01/2018 17:21, Joerg wrote:

[snip]

>>>
>>> One of the issues with my wife's car is that it is used almost
>>> exclusively for 2-3 mile trips. Grocery, church, local nursing home
>>> visits. The cat and engine never really warm up except for the few
>>> times I use the car.
>>
>> I would say that's all a very good excuse for an Italian tune-up!
>>
>
>That is my plan except we have that dreaded 65mph speed limit in the US.
>In Germany an hour on the autobahn pedal-to-the-metal would be easy to
>do (cars there are usually full-throttle proof). On a Sunday afternoon
>when all the others are sitting in front of their TV watching soccer.
>
>We've go tough hills around here but in the end you always have to come
>back down and that's where everything cools way down.

We have 65mph limits around here, too... but no one pays them any
attention... not even the COPs... need to keep the traffic moving.

Around noon drove to Ahwatukee and back 80+/-1mph ;-)

[Joerg]

On 2018-01-30 14:45, Jim Thompson wrote:
> On Fri, 19 Jan 2018 13:00:51 -0800, Joerg <ne...@analogconsultants.com>
> wrote:
>
>> On 2018-01-19 12:38, Mike Perkins wrote:
>>> On 19/01/2018 17:21, Joerg wrote:
>
> [snip]
>>>>
>>>> One of the issues with my wife's car is that it is used almost
>>>> exclusively for 2-3 mile trips. Grocery, church, local nursing home
>>>> visits. The cat and engine never really warm up except for the few
>>>> times I use the car.
>>>
>>> I would say that's all a very good excuse for an Italian tune-up!
>>>
>>
>> That is my plan except we have that dreaded 65mph speed limit in the US.
>> In Germany an hour on the autobahn pedal-to-the-metal would be easy to
>> do (cars there are usually full-throttle proof). On a Sunday afternoon
>> when all the others are sitting in front of their TV watching soccer.
>>
>> We've go tough hills around here but in the end you always have to come
>> back down and that's where everything cools way down.
>
> We have 65mph limits around here, too... but no one pays them any
> attention... not even the COPs... need to keep the traffic moving.
>
> Around noon drove to Ahwatukee and back 80+/-1mph ;-)
>

I drove the Toyota pretty hard but mostly in the mountains where I was
mostly alone. Though you have to be careful, in some areas they may not
find you for huors or days if you fail to negotiate a turn.