[PaulDay]

To diagnose if it's working properly, remove the rubber hose and place your finger over the end of the hose while having someone stepping on the gas, you should feel the vacuum suction changing.

If you feel the vacuum changing, then the valve needs to be replaced. If there's no change in vacuum, then you'll need to be looking at the part that controls the vacuum to the valve.

When replaced, there should be instructions on the proper placement of the rod.

Not for nothing, but to me, from the last photo it seems like the far hole looks to be clean, like that's where the rod originally was. Also, your very first picture shows the rod in the far hole. Your posts are a little confusing about how the rod was fitted, or even replaced in the beginning?

Anyway, a simple test for vacuum will tell you if you need to replace that unit, or if the problem is further up the line.

Good luck.

Have a good day.

 

[sistermoon2500]

I'm not sure how delicate that power valve's internal parts are but I wouldn't run the engine with the arm essentially frozen where it is since it could damage something such as a membrane.

it's also possible that retaining plate is pressed onto the butterfly shaft and has let go where the plate will just rattle around without actually being able to spin the shaft to move the butterfly. I'd disconnect the arm and try to move that plate by hand to feel and hear if the butterfly is actually moving. if it's not, you'll need to fix it.

With the arm disconnected start the engine and watch if the power valve moves the arm just to make sure that aspect works. You may have to have someone work the gas pedal to get the RPMs to the desired range as you watch it. Or just have something recording the valve as youre working the pedal then play it back.

Hi.
Yes ive done this test before. But since i was alone i did put my phone there to record what happens when i go high rpm.. shown in Video...
The power valve doesnt move at all and its stuck in closed position ( arm pulled in ) so i released it totally from the btterfly. and yes butterfly valve works, because when i open or close it with hand i can hear engine sounds change... More obviouslly when i drive with butterfly open, the performance is really noticiable, i can hear the engine roars and pushes out all that power and i can feel it in accelration... so i manually opened the butterfly and tied it like this... so it wont get closed again.

This position also matches with the video you sent and also matches with what i feel.
Moral of story is ive been driving for a year with butterfly valve closed all the time. no wonder i felt like the vehicle had no power.
these small things which dont even pull out an error code can make big differences in car performance
i encourage everyone with a Mo check this thing out. because if its broken it wont throw an error code.
its really worth the effort.

 

[I need coffee]

Thank you for taking time and finding this, But iv read this already before @Cryogenix1 posts the video. Problem with this manual is its not saying on/off signal closes or opens the airflow. so i wanted to make sure. therefor now we can say when ECM sends ON signal, power valve will close the butter fly, so no more air. im not sure which one is the default. but my guess is default should be on signal ( airflow closed) . because when you start the car or go slow RPM is not above 3600.

You're misconstruing how the valve works. There is no "airflow closed" position. Air always flows through the intake manifold or else your engine would stall. The only thing that valve does is control what path the air takes through the intake manifold. The default position is the shorter intake runner, which works better at higher RPMs. In low to mid-range RPMs (1,800-3,600), the VIAS solenoid is energized which allows engine vacuum (suction) to pull the arm on the valve back to close the butterfly, which forces air to go through the longer intake runner--this provides more torque in this RPM band.

The yellow plastic piece on your valve actuator doesn't look original and as others have indicated it looks like it's installed wrong. The default position of the arm should be forward (toward the back of the engine compartment) so that when engine vacuum is applied it can be pulled back.

If the arm doesn't move at all while disconnected from the valve and throttling the engine then the likely problem is the VIAS solenoid. See this excellent video made by an infrequent poster on these forums that shows how the valve works and some troubleshooting tips.

 

[sistermoon2500]

To diagnose if it's working properly, remove the rubber hose and place your finger over the end of the hose while having someone stepping on the gas, you should feel the vacuum suction changing.

If you feel the vacuum changing, then the valve needs to be replaced. If there's no change in vacuum, then you'll need to be looking at the part that controls the vacuum to the valve.

When replaced, there should be instructions on the proper placement of the rod.

Not for nothing, but to me, from the last photo it seems like the far hole looks to be clean, like that's where the rod originally was. Also, your very first picture shows the rod in the far hole. Your posts are a little confusing about how the rod was fitted, or even replaced in the beginning?

Anyway, a simple test for vacuum will tell you if you need to replace that unit, or if the problem is further up the line.

Good luck.

Have a good day.

Thanks for the reply...
Just to add.. Theres only one hole in butterfly valve and its in its center. the other 2 are more like hooks. so theres only one hole for the rod to go in and when rod move forward the butterfly opens and when it goes inside buttefly closed.
In my first pics the rod was in its hole. but since the vaccum is not functioning it was always closed.
what i did was released the rod from it's home and let the butterfly free.
I need to say this again. Theres only one hole for the rod to go in... The 2 other are hooks that determines the level of closed/open state. there's no way to connect the rod to anything else except the center hole.
so i will put a before and after pic

Before.

and here is after ( rod with yellow plastic is free. its not connected to anything. its just touchign the surface of butterfly)

 

[Cryogenix1]

You're misconstruing how the valve works. There is no "airflow closed" position. Air always flows through the intake manifold or else your engine would stall. The only thing that valve does is control what path the air takes through the intake manifold. The default position is the shorter intake runner, which works better at higher RPMs. In low to mid-range RPMs (1,800-3,600), the VIAS solenoid is energized which allows engine vacuum (suction) to pull the arm on the valve back to close the butterfly, which forces air to go through the longer intake runner--this provides more torque in this RPM band.

The yellow plastic piece on your valve actuator doesn't look original and as others have indicated it looks like it's installed wrong. The default position of the arm should be forward (toward the back of the engine compartment) so that when engine vacuum is applied it can be pulled back.

If the arm doesn't move at all while disconnected from the valve and throttling the engine then the likely problem is the VIAS solenoid. See this excellent video made by an infrequent poster on these forums that shows how the valve works and some troubleshooting tips.

diaphram is the word I was looking for instead of membrane. great video.

I believe the OP mentioned his mechanic noticed the. plastic retaining clip was missing and used something else.

 

[Cryogenix1]

sistermoon2500 in your last post the picture looks different from other pics. I'm currently viewing using my phone so I can't clearly tell but it seems that the forward hole may be clogged with the remnants of the broken clip and tip of the arm. or maybe your mechanic modified that plate or flange in order to try to get things working correctly.

I guess the bottom line is if you're happy with what you have then leave it alone. it's possible one of the support components isn't working correctly such as the vacuum tank or the vias solenoid. I think the only issue youll encounter is slightly worse gas mileage.

 

[sistermoon2500]

You're misconstruing how the valve works. There is no "airflow closed" position. Air always flows through the intake manifold or else your engine would stall. The only thing that valve does is control what path the air takes through the intake manifold. The default position is the shorter intake runner, which works better at higher RPMs. In low to mid-range RPMs (1,800-3,600), the VIAS solenoid is energized which allows engine vacuum (suction) to pull the arm on the valve back to close the butterfly, which forces air to go through the longer intake runner--this provides more torque in this RPM band.

The yellow plastic piece on your valve actuator doesn't look original and as others have indicated it looks like it's installed wrong. The default position of the arm should be forward (toward the back of the engine compartment) so that when engine vacuum is applied it can be pulled back.

If the arm doesn't move at all while disconnected from the valve and throttling the engine then the likely problem is the VIAS solenoid. See this excellent video made by an infrequent poster on these forums that shows how the valve works and some troubleshooting tips.

Sorry you confused me again. On and off here looks like opposit to what they mean? On mean closed? or open? Also does open means Air goes through passage A and B? by what you are saying looks like Off means that
In manual it says when its on air flows through passage A and B. But when its Off it goes through B only.
But elsewhere it says when its off air goes through Passage C
Could someone please Explain what does it mean exactly.
Also in your video this guys agrees with what i mentioned. more horse power at up hills and passing...
Here is the part i screenshot of the Manual.
Id appreciate if we can understand in simple language. I dont understand really what manual says...

i cant locate the Passage C mentioned below in upper pic...

 

[sistermoon2500]

sistermoon2500 in your last post the picture looks different from other pics. I'm currently viewing using my phone so I can't clearly tell but it seems that the forward hole may be clogged with the remnants of the broken clip and tip of the arm. or maybe your mechanic modified that plate or flange in order to try to get things working correctly.

I guess the bottom line is if you're happy with what you have then leave it alone. it's possible one of the support components isn't working correctly such as the vacuum tank or the vias solenoid. I think the only issue youll encounter is slightly worse gas mileage.

thank you again for taking time to check all the pics..
Let me make it simple.
The rod has been released a year ago and had no plastic attached to it. The rod alone is metal which the hole in the butterfly is to loose for it. so it needs a plastic part which attaches to the rod and makes teh rod thicker so it will get in the butterfly hole, therefor it sticks to it and wont come out by itself.
my mechanic saw it doesnt have that plastic part so he thought its missing by accident. so he added one himself. and stuck the rod in butterfly hole. Turns out the previous owner knew the power valve doesnt work so they released it from the butter fly.
what i did wasi just released it again. the rod is not attached to anywhere. i just didnt want to break the plasctic or i could have pulled it out too.
all i wanted to know was which way the butterfly valves allows more air. which your video shown it perfectly.
But again @I need coffee coffee uploaded another video which confused me...
his video says when butterfly is closed, since theres less air resistant the engine output increases...
But it doesnt make sense with what manual says and what i experienced. usually when you want to pass or go uphills Engine RPm goes up right? So the passage A and B should be open for more air. ( butterfly open)
Also manual has some paradox too.
Im all confused... lol
You're right i gotta stick to what works for me...
But its still very intersting to learn

 

[Cryogenix1]

This is what's confusing me. The "before" picture shows that plate without a hole, but the next pic with the ziptie shows a hole. Did you somehow remove that plate and spin it around so that hole is now on the lower-right and hidden by the yellow clip?

Yes, that retaining clip is absolutely essential in order for that arm to work correctly. The plunger arm doesn't actually seat inside of that center-shaft portion, it sits in that forward plate hole and snaps into the plastic clip.

EDIT: Actually, in looking more closely at things, it seems that either you're using pics from two different vehicles, or that the end plate housing was changed (the big round piece that mates to the intake). I say this because a recessed circle appears to be missing on the ziptied pic. Just down and to the left of where the two screws fasten the power valve to that big round plate, I see a small circle on the before pic that's missing in the later pic (perhaps just a lighting issue). And unless it's simply another lighting anamoly, the petina of those plates looks a bit different. Plus, there's a small, rectangular stampe just left of the butterfly shaft area (firewall side) that looks different in both pics. But maybe you cleaned everything up which merely exposed it more. However, even that stamped circle at the 11 O'Clock position (to the left of the butterfly shaft area) seems different.

 

[Cryogenix1]

In manual it says when its on air flows through passage A and B. But when its Off it goes through B only.
But elsewhere it says when its off air goes through Passage C
Could someone please Explain what does it mean exactly.
Id appreciate if we can understand in simple language. I dont understand really what manual says...
View attachment 55803
i cant locate the Passage C mentioned below in upper pic...

Where are you seeing something that mentions a passage C? The diagram does seem a bit unclear, but mainly because the depiction of the butterfly isn't as obvious as I think it should be. Attached is a diagram from a different Nissan engine that at least shows the butterfly instead of just a line or broken line.

 

[I need coffee]

Sorry you confused me again. On and off here looks like opposit to what they mean? On mean closed? or open? Also does open means Air goes through passage A and B? by what you are saying looks like Off means that
In manual it says when its on air flows through passage A and B. But when its Off it goes through B only.
But elsewhere it says when its off air goes through Passage C
Could someone please Explain what does it mean exactly.
Also in your video this guys agrees with what i mentioned. more horse power at up hills and passing...
Here is the part i screenshot of the Manual.
Id appreciate if we can understand in simple language. I dont understand really what manual says...

i cant locate the Passage C mentioned below in upper pic...

Technically, air always runs through the short intake runner because that is connected to the lower intake manifold. When the VIAS solenoid is energized, air is diverted first to the long intake runner and then to the short runner. Lengthening the path that air must travel to reach the engine improves torque in the low to intermediate engine speed range, but at the expense of high RPM power. By using a variable-length intake system, engine performance can be maximized throughout the engine's entire RPM range.

As far as what "Passage C" is--I don't know. The diagram points to the VIAS solenoid. Looking at pictures of some there appears to be a plastic cap on the top. Does this come off to reveal an access port to do vacuum checks? Nevertheless, it doesn't really matter what Passage C is. If you pull the vacuum line from the power actuator and feel vacuum there when the engine is between 1,800-3,600 RPMs then the system up to the valve is working as it should.

 

[Strontium]

This is what's confusing me. The "before" picture shows that plate without a hole, but the next pic with the ziptie shows a hole. Did you somehow remove that plate and spin it around so that hole is now on the lower-right and hidden by the yellow clip?

Yes, that retaining clip is absolutely essential in order for that arm to work correctly. The plunger arm doesn't actually seat inside of that center-shaft portion, it sits in that forward plate hole and snaps into the plastic clip.

EDIT: Actually, in looking more closely at things, it seems that either you're using pics from two different vehicles, or that the end plate housing was changed (the big round piece that mates to the intake). I say this because a recessed circle appears to be missing on the ziptied pic. Just down and to the left of where the two screws fasten the power valve to that big round plate, I see a small circle on the before pic that's missing in the later pic (perhaps just a lighting issue). And unless it's simply another lighting anamoly, the petina of those plates looks a bit different. Plus, there's a small, rectangular stampe just left of the butterfly shaft area (firewall side) that looks different in both pics. But maybe you cleaned everything up which merely exposed it more. However, even that stamped circle at the 11 O'Clock position (to the left of the butterfly shaft area) seems different.

View attachment 55806
View attachment 55805

In the first picture, the notch (where the zip tie is holding the plate in the second picture) is down over a pin sticking out of the bottom. I presume this is the closed position. The pin/notch is to keep the valve from rotating the other direction and stopping closed. First picture, valve is closed. Second, it's held open by the zip tie. Also, in the first picture, it looks like the rod is in the correct hole (which is on top, while the valve is closed). When the solenoid actuates, it pushes the rod out (back) which turns the valve to the open position.

EDIT: Nevermind, I'm blind. We can't really see how many notches there are. It would make sense if there were two notches facing inwards on opposing corners of a triangle, with the pin in the middle. Preventing the valve from swinging too far either way past 90 deg or whatever angle they're using for the valve open position.

Also, looks like there is no center "hole". It looks like the flattened end of the valve's center rod or a pin to hold the plate.

 

[sistermoon2500]

Sorry everyone for confusion...
I could have guessed the first pic is not showing the edges very clear. I highlighted the butterfly shape in these 2 pics.
the first one is before i release the rod from it which is in closed position...
Second pic is after i released the rod and put the butterfly in open position.. ANd i used a ziptie so it doesnt move.

And second pic after i pulled out the rod out of the butterfly hole. ( butterfly has only one hole for the rod )

 

[DreamCar5683]

This system is designed to give you the most power when the car needs it at all ranges of RPMs.
When you tie this valve in a fixed position you’re sacrificing power elsewhere. Usually wit this type of system you’re either sacrificing low speed power or top end power.
I recommend you repair the system correctly so it operates as designed.

 

[Pilgrim]

^^^^ Absolutely agree.

That cable tie should be used only long enough to get the correct part and install it so the system works as designed.

 

[sistermoon2500]

This system is designed to give you the most power when the car needs it at all ranges of RPMs.
When you tie this valve in a fixed position you’re sacrificing power elsewhere. Usually wit this type of system you’re either sacrificing low speed power or top end power.
I recommend you repair the system correctly so it operates as designed.

Thank you for the info. A mechanic in this forum told me "this increases fuel economy, if you like u can tie it so it will be always open and powerful" guess he was wrong?
My experience sofar Fuel economy got much better after i tied it open.
2: speed below 100kmph is great but i have a feeling at higher speed its not effective anymore. so what you're saying makes sense.
Could you please dig more into how does this valve work in different speed/rpms so we get a better and clearer picture of whats going on ?
Thank you

 

[Pilgrim]

Thank you for the info. A mechanic in this forum told me "this increases fuel economy, if you like u can tie it so it will be always open and powerful" guess he was wrong?

With any respect due to this mechanic - there are posters on this forum who know a helluva lot more about Muranos than most mechanics. That comment is typical of someone who doesn't understand a problem and wants to get the customer out the door.

Nissan is like any other car maker - they design for the best possible gas mileage because it benefits them in sales and in meeting governmental requirements. I have seen things done to cars before which "increase gas mileage" and eventually damage the vehicle.

And the obvious answer is that your car will drive, act and wear as designed when the equipment on that car is working as designed. Your goal should be to get the right part installed properly and restore the car to operating as designed. IMO no "clearer picture" is needed.

 

[sistermoon2500]

With any respect due to this mechanic - there are posters on this forum who know a helluva lot more about Muranos than most mechanics. That comment is typical of someone who doesn't understand a problem and wants to get the customer out the door.

Nissan is like any other car maker - they design for the best possible gas mileage because it benefits them in sales and in meeting governmental requirements. I have seen things done to cars before which "increase gas mileage" and eventually damage the vehicle.

And the obvious answer is that your car will drive, act and wear as designed when the equipment on that car is working as designed. Your goal should be to get the right part installed properly and restore the car to operating as designed. IMO no "clearer picture" is needed.

yep this mechanic is a member of this forum and didnt charge me anything, he had a murano himself. im not looking for gas millage. and he said when butterfly valve is open there will be more fuel burnt. im ok with that in exchange of more power/speed. But @DreamCar5683 is saying when butterfly is open. its sacrificing something in higher speed. I think it makes sense. Like i can eaily reach 100 (60mph) but after that when RPM stays lower i think i mean i feel the butterfly valve should be closed for more performance...
I think this part in manual explains it but i cant quite understand it...? In here On mean closes. Off means open.
So looks like what i did was to forced it into "off" signal ( butterfly open) .
However in @Cryogenix1 vid it shows when butterfly is open, both passages are open! But in manual says otherwise.
Now im confused. could manual be wrong?

 

[I need coffee]

yep this mechanic is a member of this forum and didnt charge me anything, he had a murano himself. im not looking for gas millage. and he said when butterfly valve is open there will be more fuel burnt. im ok with that in exchange of more power/speed. But @DreamCar5683 is saying when butterfly is open. its sacrificing something in higher speed. I think it makes sense. Like i can eaily reach 100 (60mph) but after that when RPM stays lower i think i mean i feel the butterfly valve should be closed for more performance...
I think this part in manual explains it but i cant quite understand it...? In here On mean closes. Off means open.
So looks like what i did was to forced it into "off" signal ( butterfly open) .
However in @Cryogenix1 vid it shows when butterfly is open, both passages are open! But in manual says otherwise.
Now im confused. could manual be wrong?

You're making this way more complicated than it needs to be. The system is in place to maximize engine performance over a wider RPM range compared to what would be possible if a single-length intake runner was used. It used to be that engineers had to make a choice between low-mid RPM performance vs. high RPM performance and the intake manifold runner length was chosen accordingly. The widespread use of sequential fuel injection enabled variable length intake systems to be implemented since only air is moving through the intake manifold so you can tune the manifold for optimal performance. In the system that Nissan uses, one runner is used for the 1,800-3,600 RPM band while another is used for other RPM ranges. By disabling the system via disconnecting the power valve arm or locking it in one position, you are sacrificing engine performance in some RPM band which is what other posters have been trying to tell you. If you want your engine to perform optimally at every engine speed, fix the VIAS system.

If you want to learn why these systems improve engine performance across a wider RPM range over single-length intake runners then watch this short video by a YouTuber who used to be a mechanical engineer for an auto manufacturer as he explains how these systems work.

 

[sistermoon2500]

You're making this way more complicated than it needs to be. The system is in place to maximize engine performance over a wider RPM range compared to what would be possible if a single-length intake runner was used. It used to be that engineers had to make a choice between low-mid RPM performance vs. high RPM performance and the intake manifold runner length was chosen accordingly. The widespread use of sequential fuel injection enabled variable length intake systems to be implemented since only air is moving through the intake manifold so you can tune the manifold for optimal performance. In the system that Nissan uses, one runner is used for the 1,800-3,600 RPM band while another is used for other RPM ranges. By disabling the system via disconnecting the power valve arm or locking it in one position, you are sacrificing engine performance in some RPM band which is what other posters have been trying to tell you. If you want your engine to perform optimally at every engine speed, fix the VIAS system.

If you want to learn why these systems improve engine performance across a wider RPM range over single-length intake runners then watch this short video by a YouTuber who used to be a mechanical engineer for an auto manufacturer as he explains how these systems work.

Thanks for the video.
Today i used the service functions on cvtz50 to inspect the issue...
In the engine menu there's a option to turn VIAS valve 1 and 2 on and off ( same thing when u put your foot on pedal to raise RPM up above 3600)
I discinnected the hose from power valve acuator and when i tried VIAS on/off the vaccume is working. Problem is acuator... The vacume can pull back the acuator to close the butterfyback... But when ECM sends OFF signal even though the theres no more air sucking in from the hose... But power valve acuator doesnt go back to its place.
i read the service manual it says "Repair or replace power valve actuator" ...

I looked onlike for the part...
its expensive around $200...

So i was wondering since the Service manual says "repair or.."
Is it repairable ?
thanks