How does the Suction Jet Pump work?
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  1. #1
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    How does the Suction Jet Pump work?

    I am in the middle of replacing some PCV parts on my wifes 02 Passat AWM. I was cleaning the various hoses behind the intake manifold along with my suction jet pump. It looks to be in good shape. Air only goes through one way (see first picture) like it is supposed to, but I'm not sure what is supposed to be happening with the smaller line coming out of the bottom (first picture again). When vacuum is applied to the pump, and the air flows through the pump, following the direction of the arrows, is air supposed to go in or out of the bottom line? Mine does neither. I'm assuming it is supposed to be sucking in as the line that connects there comes from the breather valve.

    The red arrows indicate the direction of airflow. Can anyone tell me which way air is supposed to go from the bottome line? (The green or blue arrow)



    Here is a cutaway view of the pump. The area circled in yellow seems to be clogged up on mine. Either way, no air moves through here. Again, the red arrows indicate the direction of airflow



    Does anyone have one of these pumps handy that they would be willing to suck on to see that happens? I'm sure everyone on here would appreciate it.

    Mike
    Last edited by woodardhsd; 03-25-2007 at 09:51 AM. Reason: spelling

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  3. #2
    Super Stealth Retired Moderator JayTheSnork's Avatar
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    I'm thinking the flow goes along the blue arrow. since it appears you pulled these pix from the audiworld site, did you read the writeups there?

  4. #3
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    It's a venturi chamber, much like a carburetor. The air going past the side tube sucks the air in the side tube along with it via the bernoulli effect.

  5. #4
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    So, if air wont flow through the side tube, I have a problem?

    What were these engineers thinking trying to suck 250 degree oil fumes through a tiny pinhole and into the intake? The complexity of the PCV system is driving me crazy.

    Mike

  6. #5
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    The engineers were thinking that venturi chambers don't work if the holes are big. Anyway, yes, it stands to reason that replacing the unit would do some good, especially if you've confirmed that there is no suction on the angled hose nipple.

  7. #6
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    Yeah, you're right.

    I guess the whole thing is just frustrating. Half of those hoses are squishy from the oil eating away at them, and the other half are halfway stopped up with oil sludge. Plus, the breather tube coming off of the oil filter bracket broke as I was removing the hose clapms. It's gonna cost me $100 plus to get this crap working right. I guess I'm just used to Hondas where I can go to autozone and get a $3 PCV valve and be done with the whole thing.

    Guess I'll just bite the bullet and replace it all. Hopefully it will be the last time.

    Mike

  8. #7
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    You can fix the squishy rubber hoses by replacing them with aftermarket silicone hoses. Silicone is inert to pretty much anything. The sludge will also be less likely to stick to silicone hoses because the two chemicals are incompatible.

    Don't feel bad dude, if this somehow turns out to be the worst of your problems, you're $9900 less in the hole than I am.

  9. #8
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    Do you have any idea there I can get these silicone hoses from? If it was just a straight piece, it would be no problem, but this is a Z shaped piece that goes from the breather valve to the suction jet pump.

    It is number 10 in this picture



    Mike

  10. #9
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    Quote Originally Posted by woodardhsd View Post
    Yeah, you're right.

    I guess the whole thing is just frustrating. Half of those hoses are squishy from the oil eating away at them, and the other half are halfway stopped up with oil sludge. Plus, the breather tube coming off of the oil filter bracket broke as I was removing the hose clapms. It's gonna cost me $100 plus to get this crap working right. I guess I'm just used to Hondas where I can go to autozone and get a $3 PCV valve and be done with the whole thing.

    Guess I'll just bite the bullet and replace it all. Hopefully it will be the last time.

    Mike
    Take the price you'd expect for a part and multiply it by anywhere from 2 to 10. There are a lot of good online sources where stuff costs about half of what it costs at the dealer.

    Here's where it pays off. Last week my wife was rear ended by a Chevy Cavalier or some similar domestic crap. His radiator split, hood folded, windshield shattered and airbags deployed. From 20 feet you can't even tell anything happened to her wagon.

  11. #10
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    Silicone hoses are quite flexible when new; you shouldn't need to get special pieces, at least not for the thin hoses.

    To be honest, I've never found a good source for the silicone hoses, I just know what their benefits are. Other people here can tell you where to buy them.

  12. #11
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    Unfortunately, I was in a bit of a bind yesterday so I was forced to pay dealer prices for #2 and #10 in the picture above and for the suction jet pump. They really weren't that much more than 1stvwparts.com when you factor in the cost of shipping.

    By the way, in case anyone is interested, air should flow through the side tube both ways. By pump was definitely clogged up where the yellow circle is because no air would flow through at all.

    Mike

  13. #12
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    Erm...yes, there's no one-way valve to keep air from flowing out through the side tube, but in terms of how it will actually operate when installed, air will only flow in.

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