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Old 09-19-2017, 08:01 AM   #1
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Secondary air pump check valve question

With the help of all the great info provided here I removed the secondary air pump from my Spec Boxster. The question I have is, one side of the check valve goes to the carbon canister, where dies the opposite end go if anywhere? During the disassemble of the intake and pump parts I found the check valve and its hose just lying on top of the engine and not connected to anything. Per the drawing in the manual one side goes to the canister. No where in the manuals could I find where the opposite end goes. It may be designed to vent to atmosphere and not be connected to anything on that side of the check valve. I searched in the engine for a place it could go but no luck. Thanks for your help.
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Old 09-19-2017, 10:26 AM   #2
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Hello Black Sweeper There is an image on this link that you may find helpful. https://www.renntech.org/loren/images/air_pump.gif

1 - Secondary air injection pump

2 - Air change-over valve

3 - Electric change-over valve

4 - Non-return valve

5 - To the cylinder heads

6 - Vacuum reservoir

7 - To the intake air system

Last edited by derfo; 09-19-2017 at 10:30 AM.
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Old 09-19-2017, 11:22 AM   #3
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hmmm - the sai system doesn't connect to the carbon canister. as per the image linked by derfo, it connects to the engine in two places (remove the two #5's in the diagram - replace with blanking plates) to the vacuum system (remove #2 and #3 and plug, or use new fittings to clean up the system - #6 and #7 stay; there may be additional vacuum connections - based on year, transmission type, etc.) and to the air pump (#1) which is also removed (vents to atmosphere).

the carbon canister (in the front passenger fender well) has three connections - vent to fuel tank (stays) vent to rear of car (remove) and vent to solenoid valve (found in under the intake manifold) which then connects to intake plenum (one of two hoses to the plenum, where the other is to aos) - remove and plug plenum.
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Old 09-20-2017, 04:04 AM   #4
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The check valve in question (#7 in the diagram, white/ black plastic part) connects to the rubber intake tube. Each end of the tube close to the plastic intake manifold has a tiny hole where the check valve port inserts to. The other end of the check valve/ hose connects to the vacuum reservoir, not the (carbon) canister. You may have vacuum leak with the check valve disconnected, unless the intake hole is plugged.
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Old 10-02-2017, 11:33 AM   #5
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Okay I'm puzzled. My item number 7 fell out of the rear intake plenum tube which is not vented in side. How can this valve work if it is in a non-vented hole? It is on a 3 way 'Y' with hoses on almost opposite sides and the valve's white end pushed into the blocked tube of the intake plenum rubber tube. I think I understand it is not part of the Sai system. Is that correct?. Thanks, Bill
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Last edited by bcinphx; 10-02-2017 at 11:37 AM. Reason: Confusing?
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Old 10-02-2017, 11:47 AM   #6
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That is where vacuum is drawn from. The negative pressure in the intake draws a vacuum on the line leading to the vacuum reservoir.
That hole that the check valve inserts into should go all the way through the plenum. The SAI needs vacuum, so in that sense it is part of the SAI system.
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Old 10-02-2017, 04:20 PM   #7
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Well it was laying down underneath the intake tube. I assumed that it came out of that hole that does not go all the way through. But is there maybe another place that I have to find to insert this valve into? Or will I have to drill a hole thru into the tube? Trying to fix 0410 and 1411 fault codes that come on (cel) every 150 miles or so..
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Old 10-02-2017, 04:48 PM   #8
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You definitely need to find the correct hole. Don't drill a new one. Lack of vacuum caused by your situation will absolutely cause those codes.

I'm not 100% sure where it goes on the '02 plenum. You should start a new thread in the general discussions area asking for a picture of its location.
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Old 10-02-2017, 04:56 PM   #9
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Try this thread: Need help with vacuum lines
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Old 10-02-2017, 07:29 PM   #10
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Quote:
Originally Posted by bcinphx View Post
Well it was laying down underneath the intake tube. I assumed that it came out of that hole that does not go all the way through. But is there maybe another place that I have to find to insert this valve into? Or will I have to drill a hole thru into the tube? Trying to fix 0410 and 1411 fault codes that come on (cel) every 150 miles or so..
I had the same problem. The check valve just fell out of the rubber manifold. I inserted a barbed brass fitting from the hardware store in the rubber manifold. This was very tight. I then put a piece of 4mm ID silicon tubing on the other end of the barbed fitting. The piece of tubing was like 6" long and I inserted the check valve into this tubing. Everything was nice and tight and leak proof.

I also found that the black plastic domed vacuum reservoir would not hold pressure.

I took the vacuum line off the installed reservoir and used a hand vacuum pump to see if it would hold vacuum.....NO it would not. Replaced the reservoir with a new one for all of $21 from Partsgeek.

the reservoir is way down under the manifold.......To install the reservoir properly you have to remove the panel behind the passenger seat and take out the alternator. Maybe I will do that later.

I installed it temporarily with a zip tie and longer vacuum line.



Here is a look at the check valve. You cannot see where it goes into the manifold, but it is similar to the brass barbed fitting seen here. The manifold connection is under that big hose behind the brass fitting.


On the lower left in the photo below, the electric solenoid valve is for the transmission cooler vacuum valve. I hooked up the vacuum gauge here to see what amount of vacuum I had. You can see the new high temp vacuum hose installed.....it is MUCH better than the black rubber stuff used by Porsche. Eventually I will replace all the rubber show connectors with brass fittings and silicon hose.

I ended up with 18" Hg which is good. You should have between 15 and 20 " of mercury. My codes went a way and I was able to pass CA smog!!!!!


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Last edited by boxfix; 10-02-2017 at 07:41 PM.
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