Okay To Temporarily Remove Intake Plenum Stay?

[turbocruiser]

Hi all, wanted to write to ask if it is okay to temporarily remove the "intake plenum stay" that supports the intake plenum. I want to temporarily remove it to replace the VSV; it looks like removing it would make much more space to squeze hands and tools in to replace the VSV. I would not drive the rig this way but I would run the rig this way before and after the VSV R&R to test the multimeter readings before and after. Seems harmless but before breaking something, thought I would ask the experts here. Thanks I appreciate the advice.

 

[cruiserdan]

If you are refering to the stamped steel bracket that bolts in the middle of the plenum and then drops down to the block, the 93-94 models don't even have one there. You should have no trouble.

 

[turbocruiser]

If you are refering to the stamped steel bracket that bolts in the middle of the plenum and then drops down to the block, the 93-94 models don't even have one there. You should have no trouble.

Yes, that is what I am refering to...it looked safe to remove but was not sure and in the FSM for R&R of the VSV, I do not think they mention this shortcut. Thanks Dan, off I go to replace the VSV!!!

 

[landtoy80]

How do you pronounce "plenum"???

 

[turbocruiser]

How do you pronounce "plenum"???

Kinda like the first part of "plenty" or the first part of "plethora". "Pepe, would you say I have a plethora of plenums?" "Yes, el guapo, you have a plethora of plenums!" "Pepe, do you know what a plethora is?" " No, el guapo, but I'm sure you have a plethora of something!" Old lines from three amigos. Sorry.

Hey, how come phonetic of all words is not spelled like it sounds?

 

[LandCruiserPhil]

What is the big word for VSV???

Phil

 

[turbocruiser]

What is the big word for VSV???

Phil

Vacuum Sensing Valve, aka, TFTTFWMETIDR - The Fawking Thing That Fawks With Me Every Time I Drive Recently! I cant wait to replace that thing!

 

[LandCruiserPhil]

Vacuum Sensing Valve, aka, TFTTFWMETIDR - The Fawking Thing That Fawks With Me Every Time I Drive Recently! I cant wait to replace that thing!

Thanks Turbo - one more question....What is the VSV function and how do you know when it's bad or not working properly?

Phil

 

[turbocruiser]

Thanks Turbo - one more question....What is the VSV function and how do you know when it's bad or not working properly?

Phil

My understanding, and this may be somewhat off, is that the VSV senses the appropriate amount of vacuum present whenever the vehicle is operating within the ranges of vehicle speed, motor speed, and load, where the EGR valve should open. The VSV allows the EGR valve to reintroduce exhaust gas into the combustion chamber. When the VSV fails the way mine has failed, it does not allow any or enough EGR flow and therefore, it pulls a P0401 code for EGR flow insufficient. Under boost of any amount, the VSV should not allow the EGR to reintroduce that exhaust gas either. So if one were to pull the opposite of insufficient EGR flow, it could, I assume, mean the VSV is stuck open and therefore the EGR is always reintroducing that exhaust gas causing poor performance, poor economy, harsh idle, etc. Of couse my code could come also from a bad EGR valve and I cannot seem to cause poor idle by applying vacuum to the EGR so that might mean I have a bad EGR as well. If that is the case, I'm going to be another statistic of people who have replaced each and every frickin component of the EGR system!!! ARRRRGGGGHHHHH! At least we have CruiserDan to make this process as painless as possible!

 

[landtank]

T-Cruiser, it's the modulator that does all that you are referring to. The VSV or Vacuum Switch Valve, is a device that the ECU controls to supply vacumm to the EGR system. That's the on/off switch so to speak of the system.

 

[turbocruiser]

T-Cruiser, it's the modulator that does all that you are referring to. The VSV or Vacuum Switch Valve, is a device that the ECU controls to supply vacumm to the EGR system. That's the on/off switch so to speak of the system.

Okay, so are you saying that the VSV supplies the vacuum? I thought that the vacuum was either present or not due to speed, load, etc and that the VSV senses the right amount and switches "on or off" the EGR. In other words, I did not realize that the VSV supplies any vacuum, I just thought it sensed the existing vacuum naturally present based on boost or vacuum. Do not get me wrong, I do not know, I'm only asking not arguing, but I would like to learn the finer points here. Thanks. I replaced my modulator which was bad but I still pulled the P0401. Then I read something from someone here that even when using the FSM method for testing the VSV, it can test fine with the multimeter but still fail from soot and such stuck somewhere inside so that the switch no longer switches. I really would like to learn more of about this so thanks.

 

[landtank]

Checking the VSV with a VOM is only checking the resistance of the coil in the assembly. That doesn't mean the passage is not blocked.


On the bottom of the modulator there is a tube that runs to the bottom of the EGR valve. This senses the pressure at the valve via a diaphram in the modulator to, well, modulate the operation of the EGR valve itself.

 

[cruiserdan]

VSV = Vacuum Swithcing Valve...............



BFD = Bernalillo Fire Department...........

 

[landtoy80]

I took my VSV apart and its a tiny electro magnet with a tiny spring and a tiny diaphragm.
It can fail do to a weak spring, tiny carbon clogged itn the tiny ports or the electro part of the magnet fails.
I don't remember if its open with or without power to the magnet.
If your modulator has failed and carbon is in the vacuum system then your VSV can fail and then work again if the tiny carbon works its way through the tiny port.

Todays word is "tiny"

 

[turbocruiser]

Okay, just removed and replaced my VSV. Seems like similar amounts of contortionism as the R&R of the fuel filter. Hope this helps someone who will want to do this in the future - remove the intake plenum stay, the stamped metal support that runs from the block by the oil level sensor up to the intake plenum. This metal thing is not on all models apparently but if you have it, have it off for this procedure. It's too late to run the rig on several test cycles so I will see tomorrow. I have a sneaking and sinking feeling that the EGR valve itself may be bad? I hope I'm wrong.

I'm still wondering about the finer points of the VSV...is it really supplying vacuum or is it just stopping and starting the EGR valve from opening and closing based on existing engine vacuum?

 

[landtank]

get out your FSM turn to page eg-114 there is a diagram on the system.

 

[Rookie2]

Don't know if it's the same for you turbo guys, but pretty easy to get the VSV out once the throttle body is out. Any reason why you didn't go this route?


Rookie2

 

[turbocruiser]

Don't know if it's the same for you turbo guys, but pretty easy to get the VSV out once the throttle body is out. Any reason why you didn't go this route?


Rookie2

Hmm, never even ever thought of that...I just saw that the intake plenum support was the top obstacle from the drivers side angle. Removing that made the process much simpler. Having a heap of extensions, swivels, and adaptors helped also. I would think that the throttle body method would make much more work out of it as opposed to removing the support and going at it from under and sideways.

 

[turbocruiser]

Forgot to add that all the little vacuum lines were free and clear and also that so far ( I cringe to say this, and B has warned me ) no P0401 since the replacement of the VSV. I'm still wondering and worrying about the EGR valve though. Also forgot to add that bypassing the tube that transitions through the plenum for the VSV would make matters even easier in terms of this procedure. You could cap the stubs at the top and bottom of the plenum and then just run one longer length of tube from the VSV up.

The only thing I regret with the whole VSV procedure is that I ordered the thing in a panic from good old Dan and then let it wait two weeks to put the fricking thing on! In my defense though, we have had horrible whether with heaps of hail and whenever we have heaps of hail, the 80 stays parked and protected in the garage. I use my trusty rusty 88 4Runner as it is peppered with past hail damage anyway. Of course, while I was using the 4Runner I re-devoted and re-dedicated myself to tens of little projects on it ranging from cooling system stuff to brakes to steering box. I'm sort of ADD that way; whatever I'm driving gets the good treatments. So I was midnight wrenching on the Runner while my 80 waited the weather. Anyway, now I wait and see if the cursed P0401 comes back!

 

[turbocruiser]

BTW, Rookie2, your sig line is super slick and super funny! Way to go! I'm still smiling from that one!