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Under the Plenum there are 2 vacuum lines 1 goes to the blow off valve at the front. Where does the other go??? mine is just hanging there. Also while I was looking to see where it goes I found anther vacuum line (off the front diff) just hanging in the breeze, where does this line go to???? Car is not running well since this has happened...

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Hey mate,

The one off the fitting on the top of the front diff should go to a u-shaped pipe thats bolted to the underside of the plenum. It is just a breather so dont be too concerned about that one. If you dont have a u-shaped pipe on the underside of the plenum to attach it to then just cable tie it up to its higher than the diff.

The other one that is next to the one that goes off the the blow off valves should be attached to a pipe that runs behind the timing belt backing plate and through to the otherside where a hose connects it to the charcoal cannister.

If you still can't find the pipes PM me and i'll get a pic for you :)

Deren

Here are 3 pics that should help you to work out where it goes.. Sorry about the quality

Having it unplugged will cause the car to run badly as its a vacuum leak under idle and when you get positive pressure (boost) in the intake manifold you will get a boost leak. Its actually charcoal canister purge line. The other little one is a vacuum signal line that actuates the diaphram and lets the purged vapours into the inlet manifold.

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The big one you point out is the BOV.

The two smaller ones are the boost from the turbo compressor covers and then back to the wastgates i believe. The ends you can see... connect to the boost solinoid.

Cant rem atm, which ones which... you'll need to know this as the solinoid only hooks up one way. The one you CANT blow through.. would come from the WG actuators.

Edited by GeeTR

Well, if your running the EBC's solinoid on the drivers side, then you can use that OEM piping; its quiet convenient running neatly behind the head there.

But if your running it on the passenger side... then clearly you don't need it.

I would try and keep the solinoid close the the WG... :wub:

  • 3 weeks later...
  • 1 month later...

My plenum is out getting chrome plated currently at the moment. When i get it back i can take a pic for you if you still need it. Like Mr GeeTR mentioned there is a small fitting on the back of the balance pipe that is supposed to have a 4mm vac tube attached to it that then runs to the firewall which has a boost gauge sensor for the factory gauge. Other than that there are a few pipes that hang down underneath near the back of the plenum which are for things like: air bypass (idle control valve), vacuum supply for the brake and clutch boosters, etc. From memory there are 3 pipes.

Edited by Godzilla32
My plenum is out getting chrome plated currently at the moment. When i get it back i can take a pic for you if you still need it.

Yes please, just to check.

I have found a pic of a stock plenum, and found a manual on line. I've marked up the "where this one goes according to manual".

My setup obviously isn't right

The fact that I have a large hose from plenum not connected to anything is a worry - will be chasing it down tomorrow (just wish I had a camera on a probe - it's f* terrible tracing anything under there).

Cheers,

John

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Ok, well the one marked AAC valve is as it says, for the Idle control valve. The one that says goes behind the AAC valve is for the Air Regulator which is for cold starts, the 3rd i can't confirm where it goes till i get home tomorrow. If it says water tube then its refering to the pipes that run behind the back of the head. Let me get back to you and i'll make sure we sort it all out properly. If any arent connected you will have a big leak under boost, not so much vacuum leak. Slightly under part throttle, off boost.

Deren

Ok, well the one marked AAC valve is as it says, for the Idle control valve. The one that says goes behind the AAC valve is for the Air Regulator which is for cold starts, the 3rd i can't confirm where it goes till i get home tomorrow. If it says water tube then its refering to the pipes that run behind the back of the head. Let me get back to you and i'll make sure we sort it all out properly. If any arent connected you will have a big leak under boost, not so much vacuum leak. Slightly under part throttle, off boost.

Deren

I had a poke around today and the tube that comes up with a bolt in it is connected soemwhere below the plenum. one of the tubes connecting to the stock boost controller is to the middle one. i've pushed the car into the sun and will have a look from underneath.

If you have a pic or can take one of your piping with the plenum out it would be a great ref :)

Cheers,

John

Ok your in luck i found a pic in my restoration thread which shows 2 of the allusive hoses. So no need to wait for me to take pics when i get home :) The angled pipe on the bottom of the plenum thats not pictured goes to the AAC valve. I hope this helps. So the rear one is the pipe that has the smaller 6mm tube connected to. It that has a yellow band on it. The middle one goes to the Air Regulator. The Angled pipe goes to the bottom of AAC valve.

That should help you sort out the problems, if not let me know. Only to happy to help mate.

Deren

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the rear/smaller pipe is the wastegate pressure source. it does connect to the "water tube" assemly but there are 2 air lines attached to it to. 1 end goes to stock boost control solenoid and the other to the wastegates via the back of the motor. it is a good source for a boost controller.

the rear/smaller pipe is the wastegate pressure source. it does connect to the "water tube" assemly but there are 2 air lines attached to it to. 1 end goes to stock boost control solenoid and the other to the wastegates via the back of the motor. it is a good source for a boost controller.

So far:

- two big ones are OK

- small one goes directly to the factory boost controller via a dodgy plastic connector (not via metal tube).

f* ony knows what the wastegates are connected to. I know they are connected to the metal tubing (I did this myself when I rebuilt turbos). There's pressure there so it must be wired up to something else.

It's almost impossible to see the tube under there. Half the wiring is obviously in the wrong spot as well.

If inly I was 4 foot tall and had tiny little hands instead of being 6'2" and 100+ kgs :cheers:

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