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  1. #1
    Saab Fan
    Join Date
    13 Jun 2019
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    Colorado
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    49
    Saab(s)
    1999 9-5 wagon
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    Vacuum issues?

    I'm just going to start a new thread instead of tagging onto an old/dead thread. I have some vacuum issues going on. 1999 9-5 wagon 2.3l 4cyl automatic...
    Issues I have been having... When I start the engine it dies right away unless I keep my foot on the gas (not to the floor but keeping it above idle). P0300 multiple misfired. Using a code reader I was able to see that the "short term fuel bank" is running at 99.2% at idle. While googling this, I find everyone pointing to a vacuum leak. I did notice some vac lines in pretty poor shape so I replaced the 10 foot or so of 3.5mm vac line. This is where I discovered that the pcv check valve is cracked in half. So I replace that. Still having the same issue. So I track back to the turbo bypass valve. It works as it should. Its not stuck open or closed. But when I remove it entirely, the engine runs fine (yes I capped off that vac line). I get no misfired, no stalling out, and fuel bank runs around 14% as it should. On the plastic tube feeding air to the intake manifold, there is air blowing out. If I put my hand over that hole, engine stalls out. I even connected a short length of wide hose from that port to the aluminum bypass tube and the same thing happens... Engine stalls. From talking to a guy at a parts store that was a mechanic, he suggested the intake hose and or outlet hose of the intercooler. I ordered 2 new hoses and cleaned the intercooler however, I suspect that those are not the problem. Could it be thw boost control valve and or hoses from there? Anyone ever had a similar issue? If it is the hoses that connect to the bcv, are those just a standard hose that I can get from a parts store or hardware store? Or are those formed and Saab specific type hoses?
    Thanks for your time and if this was covered in a different thread, then I'm sorry for wasting your time. I just haven't seen similar issues in other posts when I search vacuum leaks and or boost control valve issues

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  2. #2
    Saab Nut
    Join Date
    10 Apr 2017
    Location
    Denham, England
    Posts
    336
    Saab(s)
    2011 2.0 9-5 Aero
    Thumbs Up:   51
    If the bypass valve isn't stuck open or closed, is it actually sealing or can you get airflow through the valve. It may even appear to work but it can still leak.

    Some photographs of the offending pipes, vents, hoses etc. would be very helpful.

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  3. #3
    Saab Fan
    Join Date
    13 Jun 2019
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    Colorado
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    49
    Saab(s)
    1999 9-5 wagon
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    While I had the bypass valve off, I did test it by trying to blow through from either side and it does in fact seal. I put the intercooler back in this morning while I am waiting on the inlet and outlet hoses to be delivered some time today. I decided to check the turbines in to turbo booster and while removing the pipe that goes from MAF to turbo, I discovered that the hose that goes from the center of the 3 hoses on the BCV to that tube was disconnected. That may in fact have been my whole problem but now I need to wait on the new hoses toput it all together and test it.

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  4. #4
    Saab Fan
    Join Date
    13 Jun 2019
    Location
    Colorado
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    49
    Saab(s)
    1999 9-5 wagon
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    Wont let me upload files for posting pics. Maybe file size it too big???

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  5. #5
    Saab Fan
    Join Date
    13 Jun 2019
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    Colorado
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    Saab(s)
    1999 9-5 wagon
    Thumbs Up:   0
    Name:  Screenshot_20190906-114254.jpg
Views: 40
Size:  23.5 KB

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  6. #6
    Saab Fan
    Join Date
    13 Jun 2019
    Location
    Colorado
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    Saab(s)
    1999 9-5 wagon
    Thumbs Up:   0
    Name:  20190906_115348.jpg
Views: 39
Size:  95.9 KB
    Name:  20190906_115448.jpg
Views: 38
Size:  98.1 KB
    Name:  20190906_115457.jpg
Views: 37
Size:  63.0 KB
    Its a file size issue. Changed the way my phone takes pics and was able to get them in.

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  7. #7
    Saab Fan
    Join Date
    13 Jun 2019
    Location
    Colorado
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    49
    Saab(s)
    1999 9-5 wagon
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    Depending on when the hoses show up, I will post a follow up. I did find nothing broken or loose in regards to the turbo turbines. And I also tested the rod that opens and closes the gate (valve?) In the exhaust and that seems to work fine. Might be next Monday before I get a chance to crawl under the car to install new hoses. But I will let you know how it turns out.

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  8. #8
    Saab Fan
    Join Date
    13 Jun 2019
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    Colorado
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    49
    Saab(s)
    1999 9-5 wagon
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    Goos news is that the hoses went on without a problem. Bad news is that I still have a vacuum leak. I tried following a friends advice of spraying window cleaner around the vacuum lines to see if it causes the engine to rev up or idle down but the engine revs up and down on its own due to the vac leak causing too rich of a fuel mixture and stalling out/misfiring.

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  9. #9
    Saab Nut
    Join Date
    10 Apr 2017
    Location
    Denham, England
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    336
    Saab(s)
    2011 2.0 9-5 Aero
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    The middle image is the Boost Control Valve (APC Valve) it allows more boost if there is no pre-ignition and is controlled by the DI Cassette. Leaks from these pipes are undesirable but should simply result in a loss of boost.

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  10. #10
    Saab Fan
    Join Date
    13 Jun 2019
    Location
    Colorado
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    49
    Saab(s)
    1999 9-5 wagon
    Thumbs Up:   0
    The first image shows my turbo bypass valve. If I remove it entirely, leaving the system open to atmosphere, the car will run just fine, the short term fuel trim goes into the normal range, I get no misfiring, but the car idles high (around 1k rpm). If I close off the aluminum tube leading toward the turbo air I take, the idle drops into the normal range (about 750 to 800 rpm). If I close off the hole on the plastic tube leading to the intake manifold, the car stalls out. With that plastic tube open, I can feel air coming out of that end.

    So where do start looking now for a vacuum leak or other potential issues?

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