Y vacuum tube with loose ends coming from intake maniifold (pics)

[somerled]

Hi all - I recently purchased a very cheap 1998 Boxster 2.5 Tiptronic. I've been inspecting the engine bay today (limited knowledge) and noticed this tube/pipe which is attached to the right hand side intake manifold and splits into a Y shape with two seemingly 'loose' ends - as pictured. It is hanging just above the dipstick tube, which I know is broken.

The tube end that points left in the photos (without the black and white end) sucks air in when the engine is on. The other does not seem to. I cannot see any other loose tubing close by so I've no idea where they should connect to. I have searched this forum and others and other people seem to have similar issues but none of their wiring looks to be set up like this. I've checked all of the diagrams which people seem to respond with but none of it makes sense to me.

I don't have any CEL and the engine seems to run OK (as far as I can tell). Any ideas? Is this an issue and if so, can I fix it?

Many thanks for any help.

[blue62]

There should be a decal on the inside of your rear trunk lid shown vacuum hose layout.
Also check the link below.

http://986forum.com/forums/uploads02/Pic071473129781.jpg

[elgyqc]

Read through this thread.
Identify this small hose under AOS on '00 2.7L

[blue62]

I just now see that your in England so your car most likely does not have any SAI components.

[somerled]

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[somerled]

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[somerled]

Originally Posted by blue62

I just now see that your in England so your car most likely does not have any SAI components.

Yes I'm in the UK and this is a UK /EU spec base Boxster. So what would that mean in relation to these hoses? One end of it is still sucking in when the engine is on.

And I've checked the diagram in the link you send but it doesn't seem to correspond with the tubes I see in my engine.

[somerled]

Originally Posted by elgyqc

Read through this thread.
Identify this small hose under AOS on '00 2.7L

Thanks but I've checked that and he has a 4 way tubing piece and it doesn't seem to correspond with what I'm seeing in my engine bay... if something was actually wrong with my setup wouldn't I be getting a CEL?

[blue62]

Again look for the decal on the inside of your boot lid.
It should have the vacuum line layout.
Also look again at the link I sent.
Look at H,I,J,K,and L
One branch of your "Y" is going to go to your transmission.
The other branch is going to go to the flapper change over valve or directly to the flapper valve.
Just about every year Boxster is a little different in how the vacuum lines are laid out.
Lay out also depends on Transmission type and Country it was shipped to.
The decal on the inside of the boot lid should tell you how yours is laid out.

[78F350]

A 1998 with Tiptronic and no SAI? I just scribbled this:


Make sure the black end of the check valve is on the side connected to the intake.

[Starter986]

Ptfldr


............

[somerled]

I don't seem to have any diagram on my bootlid and my set up is different to those shown in the diagrams that you reference. I have a Y piece, not a 4 piece, and the black and white baffle bit is on one of the Y ends, not the bit that connects to the intake tube.

Seeing as the end are currently connected to nothing and apart from sucking in hot air, don't do anything - would there be any harm in just blocking the vacuum line off? The engine seems to be running OK as is and I get no CEL.

Thanks for the input.

[somerled]

Originally Posted by 78F350

A 1998 with Tiptronic and no SAI? I just scribbled this:


Make sure the black end of the check valve is on the side connected to the intake.

Thanks for the drawing. My set up seems to be different though. The black and white check valve is on the end of one of the Y pieces. The tubing is connected to the intake tube via a longer black lead and this can't be changed (can't just plus the check valve in instead). See pics.

What would the harm be to leave as is as the car has been operating like this for years. The vacuum tube sucks in hot air but otherwise engine seems to operate OK. No CEL or anything. Thanks.

[78F350]

The sketch that I posted is how your system should be set up to function correctly. Yes, your check valve is not where my diagram places it. Yours is all wrong. Someone messed with it in the past and had no idea how to reassemble it.

Right now you have a vacuum leak. Your car would prefer that you use that leaking air to control the cooling valve for the Tiptronic transmission. I believe that the default position for the valve it controls is to flow coolant and operating the valve stops coolant flow. Set it up as I pictured and it will function as designed. Plug the vacuum and the valve will remain in the default position. Leave it alone and your engine will run lean.

Here's a Buffalo, not far from where I live. She doesn't care what you do.

[Gilles]

BTW, that does Not look like a friendly buffalo...

[somerled]

Originally Posted by 78F350

The sketch that I posted is how your system should be set up to function correctly. Yes, your check valve is not where my diagram places it. Yours is all wrong. Someone messed with it in the past and had no idea how to reassemble it.

Right now you have a vacuum leak. Your car would prefer that you use that leaking air to control the cooling valve for the Tiptronic transmission. I believe that the default position for the valve it controls is to flow coolant and operating the valve stops coolant flow. Set it up as I pictured and it will function as designed. Plug the vacuum and the valve will remain in the default position. Leave it alone and your engine will run lean.

Thanks - I just wasn't sure if there were different setups for the earlier models but it's good to know someone has messed with it and it isn't as it's supposed to be. I'll try to get it fixed asap. In the meantime would it harm to engine to block off the tubes to erase the vaccum leak? Guessing not.

Thanks again!

[78F350]

Since it's a slow night at work, more original art:

[somerled]

Originally Posted by 78F350

Since it's a slow night at work, more original art:

Thanks for the drawing, appreciate the advice. I'll get it checked out by a garage to be safe.