whats up fellas,

I went and dynoed my car the other day. Noticed that my vias wasn't kicking in. Previous dynos had a dip around 3-4k when it kicked in. New dyno no dip looked like the long runner was stuck open. Losing torque on the bottom end. I advanced the timing to 16 from 14 and tuned it with the safc-II. Anyone notice this happen to them. I know it runs off of vacuum but the lines seem fine don't know if the switch is broke?

 

if your looking at the front of your motor, on the left side of the intake manifold there is a valve that I believe should be pulled by vacumm to activate the vias. When doing my dyno pull in 4th at 2k I had my friend look to see if this valve or switch would move but it didn't. I don't know if its broke or what? Anyone have any recommendations.

 

The valve doesn't open until 5k. Thats why it's not opening at 2k like you said. Read the VIAS sticky in the HOW-TO's.

 

the 02/03 vias opens earlier than the 3.0 vias. somewhere around 3800 iirc. they also operate completely differently and do not have the power valve which is known to fail in the 3.0 manifold.

 

Hmmm, didn't know that. I'll be quiet now.

 

The VIAS does not do anything after 3800 ish. Look at my dynos below (pay no attention to the lower squiggly curves)

Look at the red and blue lines, nearly identical besides on the low end. These were done back to back, one w/ the VIAS working and the other d/c'd

 

cool thanks for the responses fellas.

 

Here is a comparison of one of Kev's earlier dynos (red) with the most recent dyno (blue) :



The graphs seem to indicate that his VI is not working right: his torque curve between 1800-3600 rpms is significantly lower and there is no dip when the VI opens.

 

Yup... on the 02-03 IM, the valve is closed between 1800-3600 rpm and open otherwise.

 

Unless you have your VI hooked up to be effected directly by the vacuum lines, there are other things to check like the vacuum tank, power valve actuator, and VIAS control solenoid valve.

There are a several checks, so refer to EC-697 onwards of the FSM for details.

 

What is the EC-697? How can I check to see if my VIAS is working correctly?

 

You stated that the VIAS doesn't do anything after 3800 rpms. A lot of other threads I have read states that the vias doesn't open up until the car reaches 5000 rpms. I am not at all questioning your intellegence, I just want to make sure I am clear in my understanding. I have posted a thread pertaining to a loss of power in the lower rpm ranges. According to this, the VIAS could very well be my problem.

 

vias opens at 5000 in the 3.5 motor (from the manual)

 

This is incorrect. Puppetmaster has it right in post #9.

 

You are confusing the 00-01 VIAS with the 02-03 VIAS. As Sloppymax already posted, they function differently. The 00-01 VI is closed by default, so when the VIAS mechanism (almost always the power rod that opens the valves) is faulty, it remains closed, so it mainly affects the upper RPM ranges. On the 02-03, the VIAS has its default position as open, but is closed via vacuum and ECM control from 1800-3600 rpm, so when any part of that mechanism is faulty, the valve remains open throughout the RPM band.

 

Thank goodness...

 

Why must people post with no proof..

Here's some more open/closed dynos for you. Notice, the values are in torque, so one can determine the large loss w/o tuning in the 'low end'.

 

quick ?

would advancing my timing from 14 to 16 have affected my vias?

 

 

No .

 

Smiley hatin' ****

 

Smiley abusin' post 'ho...

 

That's what they're there for.... bro

 

Cool thanks.

I'm going to unplug the vacuum hose to see of it closes and solves the problem.

 

Nothing will change because the power valve is open by default and is closed by vacuum.

 

This is EXACTLY what I did to duplicate a non-functioning VIAS. I didn't d/c any elctrical connectors ( I didn't want a SES light), but merely unplugged the vac hose to it. Again, no vac line connected = blue line






have you ever connected or disconnected anything relating to your VIAS system, i.e changed plugs, therefore must d/c some items?

If so, this could be your problem, possibly a reverse connection and/or no connection.

Check all connections, electrical and vacuum and take it from there. If it's not an electrical or vacuum problem, it could be mechanical.

Take the 3 bolts off of the small 'VIAS service port'(for lack of a better description) and check the VIAS flap to see if it's stuck or any other malfunction is occurring.

 

I am going to replace the vias solenoid valve. Will I have to retune my car when I replace this valve since it will give my car low end torque and suck in more air?

 

Only one way to find out.

Dyno again.

 

even if it did, why pay to get another tune...when it only effects below 3900 RPMS? your generally racing above that RPM anyway...

 

If your long runner was stuck open, you'd be losing top end power. Long runners develop low-end power and short runners develop high-end power. The same principle applies to intake tubes. Power is maximized as the pressure waves generated by the valves approach the resonant frequencies of the pipes. [/geek]

 

whats up fellas,

I just replaced the solenoid valve and I noticed it still isn't opening up the long runner. I sat in my car and rev it up to 6k and had my friend check if the actuator valve moved and it didn't. I didn't unscrew the 3 bolts on the intake manifold yet to see if its a mechanical malfunction. I just wanted to see if one of you's could rev it up to 5-6k and have someone look to see if your actuator valve moves.

Also another question, would have creating the custom oil catch can affect the vacuum pressure to be affecting my vias from working properly?

Thanks,
Kev

 

It (actuator) will only move at 1.8k and 3.6k so 5-6k is not really doing anything for you.

My catch can is fine and so is the function of my actuator.

 

thanks for the response.

Mine doesn't move at all. Do vacuum tanks ever go bad? I think mine is fine because when I disconnect the 1st vacuum line from the solenoid valve on the left which is connect to the tank air was released.

Should I turn on the car and disconnect the vacuum line that is connected to the actuator to see if there is vacuum?

If that doesn't work then I will disconnect the three bolts on the left side of the intake manifold and see whats goin on in there.

 

Both of these tasks shouldn't take more than 12 minutes.

 

cool thanks again NmexMAX,

I will do these two tasks tommorow hopefully I fix it.

 

Turns out my old sensor was fine. Acuator valve is fine. Then I swapped vacuum lines to the tank and felt it sucking air from the second port on the vacuum tank so the tank is fine. When I used the power probe and connected it to the solenoid valve I felt it sucking air on the 1st port on the solenoid valve. I also checked power from the harness it it was reading power but didnt test the voltage. When I plugged in the harness to the connector and reved it nothing happened. I also checked the fuses and looks fine. What else could I check or do to fix this problem?

 

are your hoses on backwards?

 

no the hoses are fine. Hooked up as in the fsm and I looked under my friends hood. I might try to swap out his vacuum tank with mine to see if that would fix the problem. When I hookd up the vacuum line that is coming out of the intake manifold directly to the center port in the vacuum tank then put my finger on the other port of the vacuum tank I could feel it sucking. But when I would plug in the vacuum line to this 2nd port of the vacuum tank it wouldn't pull back the actuator. But when I would connect the vacuum line coming out the the intake manifold to the actuator it would pull it back.

I don't know if the ecu signal to the solenoid valve is there or what?

What else should I do?

 

bump to the top

 

Have you taken then 3 bolts off the VIAS valve and checked for mechanical issues

x10