Vacuum 1 Way Valve

Re: Vacuum 1 Way Valve (twomr2`s)

Wed, 04 Mar 2020 18:32:08 GMT

acis vsv part number is 25860-74020
its not adjustable its just a filter on the end of it thats why nothing in the service manual.
test it against the bgb specs to know if its working or not

Re: Vacuum 1 Way Valve (JME)

Wed, 04 Mar 2020 17:59:39 GMT

Reddtarga

If they won't open, it may be the VSV out of adjustment.
VSV adjustment is covered in the Gen3 motor service manual on page EG268.

ACIS does not open at 5200 RPM, the manual doesn't cover adjustment of the VSV so I figure I'll just replace it. Any idea where to find the part number?

Re: Vacuum 1 Way Valve (Reddtarga)

Mon, 02 Mar 2020 18:59:44 GMT

JME
Reddtarga

Thanks for the info. The valve snaps closed as soon as the ignition is started so that makes me think the vacuum tank and lines are OK. The valves move so the actuator works so I figure it's either the VCV or an electrical problem

Obviously your ACIS is working OK when you start the motor if it closes the butterflies, and it would appear that your hoses are all connected.
The butterflies should open again around 5200 RPM.
If they won't open, it may be the VSV out of adjustment.
VSV adjustment is covered in the Gen3 motor service manual on page EG268.

Re: Vacuum 1 Way Valve (JME)

Mon, 02 Mar 2020 18:42:37 GMT

Reddtarga

Thanks for the info. The valve snaps closed as soon as the ignition is started so that makes me think the vacuum tank and lines are OK. The valves move so the actuator works so I figure it's either the VCV or an electrical problem

Re: Vacuum 1 Way Valve (Reddtarga)

Mon, 02 Mar 2020 14:22:05 GMT

A lot of cruise problems can be related to the stop light switch, but of course it may be something else.
Does the green light come on in the instrument panel when cruise selected?
It can flash a code to tell you what fault you have.
Full testing information is in the US '91 model service manual that can be downloaded online free. Ask Google.
Check out body electrical section page BE82, Cruise Control.

Re: Vacuum 1 Way Valve (Reddtarga)

Mon, 02 Mar 2020 11:52:31 GMT

JME, I have just re written this post to make it clearer.

SW20 3SGE NA's run an ACIS, and not a TVIS.
To test: Firstly make sure that the butterflies are not rusted up and can move freely.
Reach under the activator and with your finger try and move the tab on the pivot. Can be tricky to do.

If you can move it OK, have someone start the motor and observe the ACIS activator.
If nothing happens check the rubber hoses.
Normally with motor stopped, butterflies are open.
Motor started, butterflies snap closed, meaning full length of the intake runners used for best torque.
If the revs go over 5k butterflies open, effectively shortening the intake runners for more power at high revs.

Here is a pic from the Gen3 motor manual (page EG266) that can be downloaded from the tech section on this website, and shows the vacuum switch valve (VSV) that controls it.
Although this is from the Gen 3 motor, the gen2 is similar.
The VSV can probably only be accessed from under the car.
On my '90 model the ACIS VSV is green.(The blue one alongside it is for the fuel regulator).
The vacuum is taken from the botton tube (of the 3) down on the side of the intake manifold, and goes to bottom connection on the vacuum tank.
From the center angled connection on the vacuum tank the hose goes to the center connection on the VSV.
From the angled connection on the VSV the rubber tube goes up to the ACIS activator.
Very easy to get them mixed up!!

Re: Vacuum 1 Way Valve (Falcon)

Sun, 01 Mar 2020 20:29:59 GMT

I think you'll find that it's not actually a valve at all. But rather a filter.
That hose supplies the varying vacuum of the inlet manifold to the MAP sensor.

Vacuum 1 Way Valve (JME)

Sun, 01 Mar 2020 16:52:57 GMT

I'm tracking down a vacuum problem with me Rev 1 N/A SW20, symptoms are TVIS doesn't activate and cruise control doesn't work. I have found a 1 way valve in the vacuum system (circled in red) but I'm not sure which way around the valve is supposed to face. Is it supposed to let vacuum in to the manifold (but not out) or the other way around?