DAmn.. I knew something was up with my car. Even after my y-pipe my midrange was awesome in 3rd gear but it sucked ***** after 4500 rpm. Did a visual check on the outside and the little rod was moving. But I had a gut feeling, especially after all these VIAS threads. So, I took mine apart with some helpful info from SR20DEN and a very special tool called an impact drill and removed the screws and opened up my VIAS. It was broken. Had to create a simple plan of attack to fix it so a friend and I went to Pepboys and searched for whatever we could use. And then... it was fixed. I won't release how I fixed it yet cause I need to check the long term stability of how it will handle and also for the fact that SR20DEN might release a more reliable fix. But man, do I miss that pull!

 

you can also notice if your VIAS is broken by doing a dyno and seeing if u see a small drop of Hp at the 4500 rpm level...

 

yeah i couldnt feel the difference anymore cause i have been driving so slow with my 3 pt DMV record. But man, after looking at the construction of it i can see why it would easily break.

 

Exactly which part broke?

I've had mine apart before and didn't see anything that was particularly prone to breaking.

 

I just got one in today from an .org member. It's broken like all the rest. And I think I have already found the hidden hp in it.

 

sorry about the newbie question but do the 2002-3's have vais and has anyone every tried to get it to open sooner using a window switch or other type? It seems like I read in the FAQ's that it opens up at 5200 and here you guys mentions 4500??? I know long runners help torque but it might be helpful if it opened sooner. I know the VTEC guys move their VTEC systems up so that they start making more power sooner. I know that that is a completely different set up but same theory.

 

Can you post on what you used to fix your VIAS? I know mine is broken and would like to fix it. How long did it take you to implement the fix?

 

more like a huge drop in power

broken VIAS dyno: 160 whp
new VIAS dyno: 188 whp
thats a 28whp difference starting right after 4800 rpms on the dyno

broken VIAS dyno


i've found the only sure way to tell if your VIAS is broken is the following:
1. race another 4th or 5th gen. I tried this when it was broken on a friend driving a 4th gen auto with all bolt ons from 60 mph and he took me by 4 car lengths (he thought i wasn't even racing)

2. listen to the harmonics of the car after VIAS engagement at 5100 rpms

with broken VIAS, torque doesn't change all that much (i put down 188 tq w/ VIAS broken) which deceives butt dyno results

 

my car lately has been giving me the signs of power dropping off at times when going from 5500 to 6800. I need to make a trip to the dealer. Wonder what they say... 90K miles.

 

yeah either race or open her up. Its really simple to open... just time consuming. Its a little brass cup that is used to turn the rod. If it is broken, the cup will not turn if you push the rod on the outside of the VIAS unit.

 

someone needs to post up some pictures cause I am am completly lost as to what where and when. I just need to see a picture of what cover or what not to take off. My FSM aint here.

 

what pics are you looking for?

 

ok, here you go:

the red arrow points to the actuator on the outside. When the VIAS opens up via the ECU ground signal to the vacuum solenoid, the tab flips from left to right. However, its the key collar inside the IM that is connected to the outside tab that gets stripped, resulting in the power valve not turning. You can see three of the four screws that you'll need to take out once you remove the IM. Two on top of the tab, two on bottom. There is also a plate on the other end of the IM from the tab that holds the power valve in (it slides out from the passenger side once you open it up), i believe its right under the AC condenser line

 

Larrio,

Can you or someone else who also has the knowledge, kindly post detailed steps of the entire disassembly process? Can you also estimate how much time is needed to do the disassembly?

If I follow you, I think I need to remove the IM then bolts in your picture and I should be able to see the stripped brass cup? (if broken). Reverse the step to put it all back together. Don't allow dust or dirt to fall into the IM holes when removed.

I really feel mine is broken.

 

it is quite time consuming cause the only way to access the power valve is to take off the IM first. If I replace my IM anytime soon i'd do a write up. The power valve only slides out from the passenger side, which is blocked by the AC condenser line. However the part that breaks is on the driver side, which is a pretty stupid design by nissan

check www.forums.maximaracing.org in the Maintenance section for detailed pics

 

When I discovered the power valve failure I did remove it without removing the IM. The condensor hose can be bent out of the way enough to slide the PV out of the IM.

 

Can you provide a write up from memory on how to fix it? I may just take mine apart sometime when I get some free time. I cant really hurt anything.

 

a note for people that want to try it, just make sure the spring on the end of the power valve doesn't drop into your lower IM when you pull it out

 

You dont need to remove the rod unless its broken (and i bet it isn't).
Here is how you remove the VIAS box itself.
1. Remove air intake. - this includes the hoses and the box with all the piping. You need room to work.
2. Remove the Throttle Body. Remove the 4 bolts holding it and the throttle body cables. You don't have to remove it from the car but just get it out of the way (you might want someone to hold it away from the VIAS box)
3. Remove the four screws. Be careful! these are super soft screws and if your angle is wrong when unscrewing these, all you'll get is metal shavings. I used an impact drill (SRDEN mentioned an impact driver but I didn't have one). Once they start moving it becomes easy to pop off. I recommend replacing these screws with bolts or regular screws.
4. Remove the hoses and plugs and move any plugs that are in the way.
5. Pull out the unit and watch out for the spring - it might pop out. You will see a brass cup attached to either the end of the rod or in the cup. To test if the brass cup is the malfunctioning piece, place it into the VIAS unit. make sure the hole on the bottom lines up with the tiny rod stickingout of VIAS unit. Now move the rod that is outside of the VIAS box (the one that turns). If you turn it and the cup doesnt move, then there is your problem.

Hoepfully this helps you guys.

I seriuosly doubt that the power valve itself is broken. It looks sturdy enough from the pictures.

 

ChromeSE5-

Out of curiousity, since the time you fixed your VIAS till now, how has your fix held up. I am wondering because, I too think my VIAS might be malfuncting. I don't want to open it yet until a solution could be posted. Do you feel your fix might be stable enough for others to try yet? If so, could you describe what you use and did to the VIAS to re-enable it again. Thanks.

steve...

 

hmm hacienda hieghts huh? Ill be in walnut monday night so if you want we could hook up. PM me.