3S-GE (Gen3) ACIS Vacuum Routing

[Haydz]

(Apologies in advance, large images ahead!)

Hey all, having some issues figuring out the correct vacuum routing for the ACIS system in my Gen3 3S-GE. I THINK my ACIS system is functioning 'in reverse' - i.e, the variable intake is open until ~5,000RPM and then it shuts (Which is the opposite of what it should be doing, if I've done my homework right).

Also a quick disclaimer that my SW20 has a custom intake, so it lacks the factory airbox (and any vacuum fittings that might attach to it)

I've made some beautiful artwork in MSPaint to hopefully make my photos a bit clearer with the following colours:

• Blue Hose: A wider hose that has always just been looped around and connected back into an adjacent port (no idea if this is intended or not)

• Yellow Hose: Narrow hose that connects to the ACIS actuator unit

• Pink Hose: Wider hose that connects to the intake manifold past the throttle body

• Red Plug: The red is to highlight a spare port that I've plugged - no idea if this is intended to be plugged or if it's meant to be connected to something

This first photo is taken with the engine idling - as highlighted in the orange, the vacuum seems to be holding the ACIS actuator off the 'stopper' plate (Meaning the ACIS valve is open?)


This second photo is taken with the engine and electrics turned off - as compared to the previous photo, you can see the ACIS valve appears 'shut' and has rested against the stopper plate.


And another slightly different angle (again, with the engine off)


Any help/advice/replies are much appreciated, cheers!

[GDII]

Based on the blue hoses this engine is from a Celica rather than an MR2.

Image 4 shows the GEN3 3SGE MR2 vacuum hoses.
http://jp-carparts.com/toyota/partlist. ... 3&fig=1708
Image 2 and 3 shows the Celica vacuum hoses
http://jp-carparts.com/toyota/partlist. ... 5&fig=1708

Blue Hose: Keep looped. This is for the Celica power steering pump vacuum valve for idle up. The ECU on the MR2 sorts this out.

Yellow Hose: This should connect at one end to the ACIS diaphragm as it does then to a steel vacuum pipe then it should go to the VSV electrical valve then connect to the vacuum canister. Then back up to the manifold runner. I can't quite see the port it is meant to connect to or any of the hoses.

Pink Hose: This is the hose to the MAP sensor over by the Diagnostic port or the right side of the engine bay. There is a steel vacuum pipe that takes it under the intake manifold.

Red Port: This is for the large hose with the bolt in it. For your Air Conditioning idle up.

[GDII]

Actually, that last post isn't quite right.

Blue Hose: Both AC Idle Up valve hoses connect here. The large hose from the intake hose goes onto the Red Port.
These might help along with the Celica diagrams.

[Haydz]

Based on the blue hoses this engine is from a Celica rather than an MR2.

That'd be correct, the engine's from an ST202 Celica - and huge thanks for those reference pictures and diagrams, will try study those vs. my car and figure out what's going where, as there's so many bloody lines and tubes to keep track of

The 'yellow' tube is hooked up at the one end to the ACIS diaphragm and the other end is plugged into a steel vacuum tube (as it should be) - the issue with that tube is I have no idea where it pops out on the other end of the steel tubing.

Will have a proper crack at it tomorrow though! Huge thanks for the help.

[Haydz]

Based on the blue hoses this engine is from a Celica rather than an MR2.

-I have no idea where it pops out on the other end of the steel tubing-

Quick update - I've found on the far end of the steel tubing it pops out to two open ports. I've studied the diagrams and other posts - and found that the ACIS isn't plugged into the VSV Electrical Valve (I believe - could be totally wrong!)

The two open vacuum ports on the driver's side of the intake manifold (underneath where the diagnostic port sits)


This second image is (I believe?) the VSV Electrical Valve - as you can see there's nothing plugged into it - from what I've read the ACIS is supposed to plug into it but I'm unsure exactly how.


And the last one is my dirty vacuum tank, you can see the VSV Electrical Valve(?) above it (but is obscured by the ribbed cables) - not sure if this picture's much help at all but it serves as a nice reference photo for where stuff is.


As always, will update after I've had a good crack at it.

[GDII]

If you refer to image 2 on the Celica diagrams you'll see that the 2 open ports at the diagnostic end is for the Celica powersteering idle up. For now we will focus on the ACIS but I'll come back to these larger pipes. Although you can probably bypass them completely for the MR2.

Starting from the ACIS vacuum diaphragm, the vacuum hose should run to a little steel pipe near the red port then tone port of the green/blue vsv https://images.app.goo.gl/hjYKfSbNDcZAYSdA9
Then to the vacuum cannister, then to a port on the manifold. If this is all hooked up then it should work the way Toyota designed it. The idea is to have long runners at low revs and short at high. So the butterfly should be open when idling and closed when a ice the right RPM and throttle position.

For the blue ports, these are for AC and powersteering on the Celica. For the MR2 the powersteering is not controlled using the pump vacuum switch, instead the ECU figures it out. I see one of your AC idle up hoses is connected to one of the blue port pipes. This is normally the feed hose from the main intake hose to the throttle body. For the MR2 you can take it off the blue port pipe and install it directly to the manifold where the hose with the bolt in it is connected. Just beside the pink hose fitting after the throttle body. This makes the blue ports and red port redundant.
Like the red hoses in the this video on an MR2 GEN3 3SGE.
http://cyberspaceandtime.com/QY_pmNyOeKY.video+related

The way the AC idle up is hooked up right now means when the AC is switched on you are actually sucking in unfiltered air from near the diagnostic port rather than bypassing air around the throttle body to increase idle.

[Haydz]

So the butterfly should be open when idling and closed when a ice the right RPM and throttle position.

Awesome, sorted that out and it's working as intended then - I think I was thinking of the whole system backwards /facepalm

The way the AC idle up is hooked up right now means when the AC is switched on you are actually sucking in unfiltered air from near the diagnostic port rather than bypassing air around the throttle body to increase idle.

Oh mint, I'll go fix that then haha

Thanks as always for the help!