For ****s & giggles I decided to take my VIAS box out tonight and look at it. On second look I see what SR20DEN was talking about with the cup piece rotating independent to the rod... it is a very bone-headed design. The cup piece is basically designed with free play for the spring coming out of the VIAS plastic butterfly valves. Problem is, over time (and many actuations of the VIAS) the notched hole in the cup becomes eroded, so the cup no longer rotates 100% true with the actuator rod, resulting in rotational free play that limits the movement of the VIAS butterfly valves (the more eroded, the less the VIAS butterfly valves open, resulting in hampered VIAS top-end performance, even though technically it *is* opening up...)

Only solution I could think of is buying a whole new upper intake manifold and welding the rod to the cup when it's brand new

Either way, mine is to the point where the VIAS butterfly valve rod is probably rotating less than 45 degrees, instead of 90 degrees like it should.

 

That, and/or the potential to have the VIAS butterfly valves stick partially open... which could result in hampered low-end/midrange performance...

 

this is why I would like to have someone out there do a good intake manifold that makes power for the 3.0s. There is ALOT of 4th and 5th gens that would benefit this !
I been asking around and no one is willing to do it.

 

If SR20DEN or anyone else has any tested ideas for fixing this little issue, e.g. welding that cup... I might be up for purchasing the necessary stuff to have it done. I tried a crude attempt using a soldering iron and electrical solder, but that just didn't work. (fell apart easily)
IMHO, this is a serious matter with the 2k-2k1's performance, as the latter situation (butterfly valves partially OPEN) can seriously hamper streetability of the vehicle... or result in "phantom power loss" that seems to come and go.
I believe the general design of the stock manifold is sound for street and mild performance purposes, it's just stupid crap like this that blows off the fun.

 

Say you had an extended warranty and you took the car to the dealer, could they do anything? I figure most cars with this problem don't display a symptom, but simply a lack of high-end power. What if you told them the high-end power drastically dropped off all of a sudden and then they took it apart and found the problem. Could most Nissan techs. understand something like this?

 

One guy did manage to get Nissan to replace the upper intake manifold (~$400?) ... but it took a LOT of convincing, and the key was when they ran against another Maxima of the same year and lost against it.

 

That was me - and I had dynos showing the substantial loss and they wouldn't replace it.

And I would say you have a fat chance in hell of getting them to take it apart and look at it/fix it.

 

Would it be possible to use some kind of EPOXI glue to fix that problem???

 

I considered JB Weld or epoxy, and it might work... but keep in mind it's designed so there is spring tension on the collar. If you can get it to sit in its most depressed position and fill out the whole hub of that piece with REALLY tough epoxy and get it to cure, it might just work.

I was thinking on the way to work this morning... what about removing that whole assembly and designing a custom fabricated replacement? Seems like the best way to go if you ask me...

 

I'm pondering using this as an opportunity to try eMachineShop (http://www.emachineshop.com/)... anyone have a used manifold with VIAS box? I want to source one out so I can rip it apart and design a workable replacement or fix.

 

Had the same problem and fixed it. Definitly soder won't work (to weak) so I used JB Weld Quick. I applied a little to the underside of the cup and a whole lot into the cup. Trick is positioning the cup so that it is in the closed position. Also, you need to move the rod to make sure that it doesn't stick. The rod is in a bearing so not all of the metal under the cup rotates. I wish I could take some pix but I promised myself I wouldn't open up the VIAS anymore (its fixed leave it alone lol). Good luck,
Eugene

 

yeah I'll try this as the first level fix... thanks for posting your success

 

Is there a walk through(diassembly/assembly) for inspecting your vias?

 

find the rod that is mention in other ViAS threads. turn it. it should be kinda of difficult to turn and you should hear a vacuum sound. if it is easy to turn then your vias is broken. if you need a visual inspection remove the airbox, unbolt throttle body, remove throttle cables, remove hoses and plugs connecting to vias, and remove four bolts that hold vias with a drill that has a wide flat head bit on the end. don't attempt a screw driver because i promise you that it will screw up the screws because they are super soft. When replacing the vias, you might want to replace the screws with HEX bolts or firmer screws.

 

I used a screwdriver with a fairly large philips head, applying pressure onto the screws (by pressing against the butt-end of the screwdriver) and using a pair of channel-lock pliers on the body of the screwdriver to rotate it.

I had to unbolt my throttle body and move it out of the way a little to get to the lower right screw, also.

 

Has anyone just pulled the valve out? How did it run?

 

Isn't the VIAS a considerable reason why the 5th gen has more hp than the 4th gen? Wouldn't the engine's computer realize a malfunction/break like this? Or is it that it doesn't stop it from working all together but just limits its effect?

 

Well, even if it doesn't work at all, the computer wouldn't notice. All it does is change the volumetric efficiency of the intake manifold. If the ECU sees that it consistently is losing power at the top-end, would it care? How could it tell that apart from a clogged exhaust system, clogged air filter, etc?

All the ECU cares about is making the engine run efficiently (emissions and A/F ratio wise) with what airflow is coming in.

 

I think it would be cool to have an ECU that also measures engine horsepower, that way it can determine the whether the car is running efficiently and up to spec. Obvioiusly over time both will drop, as does everything wth a car.

 

It has a huge effect, without the VIAS a 5th gen makes about the same power as a 4th gen, 30hp less.

The ECU doesn't monitor the orientation of the VIAS valves, so the only measurement it has of the VIAS's function, is the reading from the MAF at high RPMs, but there is no algorithm in the ECU to trigger an engine light if an anomaly is detected in this instance.

 

I'm subscribed to this thread now, so keep us updated as to whether this fix lasts or not. My VIAS is long since dead, as I am sure 90% of DE-Ks are with 50k+ miles. I would love a long term fix, since replacing the $400 manifold will only last you another 30-50k miles.

BTW, I put 45k a year on the max, so an intake manifold once a year is not a great idea

 

haha me too, ~45Kmi a year...

 

Wow, and I thought I was putting a lot of miles on my Max: 20k in 10 mos.

 

im still good and it is rock solid. I even used jb weld quick. I think I did the VIAS fix a while ago, maybe around july. When I checked inside a couple of weeks ago, the cup wouldn't move. I pushed it hard enough to bend a peice of the metal cup but it didn't buge the jb weld at all.

 

That is excellent. I've heard JB Weld has the general hardness of glass when it's fully cured... although I'm not sure what happens when it heats up, as it might under repeated heavy acceleration. But it's JB Kwik is supposed to withstand ~300F, while JB Weld (original) up to ~500F.

One last question- Did you JB Weld it with the cup depressed down (so it has some of the rod sticking through) or did you let it cure with the VIAS box sitting down so it cures with the cup hanging against the tip of the rod?

 

Since I already have some JB Weld laying around, I might as well give it a try. I guess the worst that can happen is it will eventually give out, and then I am just back where I started

 

The original JB Weld is stronger and more resillient than the JB Kwik. It just takes longer to cure, AFAIK

BTW, the VIAS box would likely never see 300 deg, much less 500. If it does, it's because your car is on fire

 

Yeah, I intend to do it some weekend and let it sit around for 24 hours while I twiddle my thumbs (and get my roommate to drive me everywhere )

orrrrr... if I can find an intake manifold at a junkyard... just buy that and do it separately, swapping the VIAS box onto mine when it's fully cured and functional.

PS- With my VIAS disabled and the butterfly valves reset into a fully-closed position, I am definitely noticing consistent butt-dyno gains as far as low-end and midrange torque vs. previous days. Can't wait to feel that along with a bad-azz top end.

 

Can someone post pics of the VIAS? I've never taken mine apart to see it. I'd like to know if mine is working.

 

Mine has been stuck on the low-end mode for the past 9 months (or 30,000 miles ) so I cant even remember what top end HP feels like anymore, right now the engine peaks at 4800, and by 5300 it's dead. It sucks driving a car with 5th gen weight, and 4th gen power

 

http://www.cardomain.com/memberpage/419735/12

 

http://spirilis.net/gallery/vias-teardown

check this- http://spirilis.net/gallery/vias-teardown/dsc01151

see the metal cup with the protrusion... the center hub of that cup is what's faulty. The shaft in the middle is keyed (it appears to be a small bolt with 2 sides shaved flat) and the cup fits inside it, with a similar-size slit, but that "slit" on the cup wears down, resulting in excessive free play. That's what causes the VIAS power valve to open and close incompletely.

 

Is this a design flaw that continued with the 5.5 gens?

 

Wouldn't know unless I had a VQ35DE (2002-2003) manifold open to check.

 

I remember trying to fix this POS and was trying freaking everything LOL, even electrical tape to try and fill in the cup hole HAHHAH. anyways, hmmm, the way i fixed it was to put a small coating of jb quick on the bottom of the cup. If i remember correctly, you only need to put a little bit in there. you just need this so it sticks to the inner circle of the bearing where the metal rod protrudes. Remember to JB weld the cup as if the VIAS is in closed position. From there, when the cup seems somewahte stable, "pour" jb quick into the cup and cover some of the rod. it should look like one solid mass inside. Also, I did this so that the cup is standing. After four or five hours it was mostly hard. I decided to put the VIAS back in. Drove it and well, yeah 5k heven! Checked it about two days later and the cup would not move at all. post if you have any questions.

 

I gotcha. On that note, maybe I will use the Quik stuff. I don't feel like waiting 24 hours for the crap to cure I'm already excited about my low-end/midrange torque I've seen with the VIAS power valves in the closed position (w/ VIAS disabled), I can't wait to see how 5K+ RPM is SUPPOSED to feel

 

oh yeah, remember to move the valve so that it doesn't get stuck just in case you were a little messy with the jb quick

 

So just to be 100% clear... by the time your done, is the rod protruding through the cup at all? I'm trying to establish how the cup is SUPPOSED to sit.

 

yes it is. Put the cup in like it is suppose to. The jb weld acts like a filler for the material that was disintegrated from the cup. Basically you are just filling in the hole with the rod in it and making it one piece. AIM me if you have any other questions and i will try to explain more.

 

I think I know what you mean now. I'm just worried about JB Weld oozing through the gap into the mechanism below and freezing it up... I'll figure it out.