Need help with vacuum lines - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Hi, This is a 2000 Boxster S. I took off the plastic boot to clean the inside and I ended up with 3 hoses that are not connected. Read a few posts online with vacuum hoses and I am still clueless. Would be good to get some help here. I have a Y connector here, where do the longer hose (red arrow) and the other one (blue arrow) connect to? Where does this hose (orange arrow) go to? Thank you in advance for the help Robert

There should be a switch between intake tubes for cylinder 4 and 5. The second tube should connect to the base of the switch.

This may help

Or this

I looked at those 2 diagrams before. #22 seems like to be the Y connector cable that I am holding, but where does #22 connect to? Also, the wire that goes to intake plenum isn't on either of the diagram here.

Hey Robert, Im just wondering seeing how old your post is, if you ever found out where the hose by the orange arrow leads or goes to. I'm having that problem as well. Thanks Nelgenn

I think there's a sticker in the trunk that has the vacuum hose diagram that will show you how they are connected.

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Where does #22 Hook up to? Can't seem to find it.

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Since you asked a little differently in each thread, here's a different way of answering: Exactly where it goes will depend on the year of your car and if anyone has moved stuff around on the intake before. In general, it should go where the red arrow is pointing in the picture.

In my 00 S, that picture is exactly where that vac line plugs in. It will not be visible. You'll have to dig around. If you have children you have the skills needed to find it

Found this Old Post. And the comment number 9 where the red arrow is. the Red Arrow protrusion does not go through the plenum tube on my car. It is blocked. How can the valve work ? Should I go drill it open?

#22 check valve should go in that hole. On my 2003 boxster it would slip out no barbs or ridge to hold it in. I got a 3/16 brass barbed fitting from the hardware store and some 4mm silicon tubing. I put the barbed fitting in the hole, and connected the tubing to the other end of the fitting and then the check valve. I used another barbed brass fitting to plug into the "Y" connector. Unfortunately the brass fitting into the manifold is hidden here behind a hose. I will try to get a better photo next time I am in there. I also replaced my vacuum reservoir as it was leaking. When done I had 18"Hg on a vacuum gauge I installed. After a month of messing around my car cleared all monitors in 200 miles and passed CA smog!!

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You need to take the cross tube off and find exactly where it goes. If the hole you're looking at "doesn't go all the way through", then you're looking at the wrong hole. If you drill extra holes in the cross tube, you're going to have other issues.

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Well done to pass SMog ! The cure for many of the Boxster vacuum problems is silicone hose,brass barb fittings and a Mighty Vac to test the system.Cheap enough but tedious. Your repair will outlive the M96 !

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Thanks Gelbster I know you have been down the same rabbit hole and you did influence my work. I bought a new vacuum reservoir and it would hold 15 psi of vacuum. I then hooked the same "mighty vac" type tester to the installed reservoir and it would hold NO vacuum. DUHH...... New reservoir and the hoses connections in the photo the photo let me hold 18 "Hg at idle.

For curiosity - slightly pressurize the old vac reservoir with it's base under water in a bowl.Look for bubbles and hissing when you elevate it bove the water level. This will be a satisfying diagnosis. In theory you could epoxy the base of the old leaker. Why Porsche did not use a one piece blow molded part like other manufacturers do ,I have no idea. It would have been a cheaper part too !

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sounds like you are saying it leaks at the seam at the base. I would like to test it, but the old one is still in there. I was not about to R&R the alternator to fit the new vacuum reservoir in. I was trying to meet a CA smog deadline and I knew I had good vacuum now. So I left it in place and installed the new one temporarily over near the SAI air pump. I will take the old one out when/if i have to change the alternator.

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I too am sorting through the vacuum system. Non of the diagrams I’ve seen show the second intake flapper solenoid. I had to stop looking at diagrams and start thinking about how the system worked. My problems were mostly due to a leaky accumulator tank. Also, I’m not sure why anyone would remove the alternator to get to the accumulator tank. On my 02 S the tank is right under the passenger side intake plenum. It’s a bit of a pain in the ass, but it does not require alternator removal. Perhaps the 03 is completely different, but I doubt it.

" I’m not sure why anyone would remove the alternator to get to the accumulator tank. On my 02 S the tank is right under the passenger side intake plenum ." Correct ,but for most SAI repairs there are multiple points of potential failure. Piecemeal, random replacement seldom yields a good result because of the usual Porsche problem - access. So it is often wise to test the entire system. To do that you need to remove the alternator or Intake manifold. Neither are difficult - just tedious and procedural. Ther is a recent Youtube on this that has been mentioned.

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What is #20??