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Vacuum Readings (Dipstick Smoke) 850 1994

posted by  stkelly on  Mon Aug 3 15:45 CST 2009
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last visit: Fri Aug 31 18:55 CST 2012
[RELATED]

Started the car pulled the dipstick and noticed a decent amount of smoke coming from the dipstick tube. I hooked up my vacuum meter and checked my pressures. At idle I got ~17 inches with the air conditioner running and a decent amount of smoke. With the air conditioner off I got ~19 inches at idle and almost no smoke. What pressure is normal at idle? Why is there smoke with the A/C running and none when the A/C is off? With the A/C on it seems to me there is too much smoke coming from the dipstick tube, enough to burn the top of the actual dipstick. Does anyone have any suggestions as to where to start looking? I checked as many elbows as I could and they all looked good. The cruise control doesn't work but I don't think it's due to a vacuum leak, unless someone here thinks that is probably the reason.

I appreciate any feedback!

Thanks in advance.

It's a 94 850 turbo with 205K miles.

Scott
--
Scott K - 1994 850 Turbo








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    Vacuum Readings (Dipstick Smoke) 850 1994

    uid 47978's pic
    posted by  FCP Euro on  Thu Aug 6 07:22 CST 2009
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    last visit: Fri Jun 21 05:36 CST 2013
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    Even tho the PTC is clean, the oil separator box or one of the hoses could be clogged. Was the PCV ever done?
    --
    FCP Groton








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      Vacuum Readings (Dipstick Smoke) 850 1994

      posted by  stkelly on  Thu Aug 6 11:45 CST 2009
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      I replaced the PCV system at 170500 (with the kit from FCP roton :-) ). I hope it didn't get clogged up this soon. It seems to me that if the PCV system was clogged it would smoke all the time not just when the A/C is on. I'm not sure what else to really look at.

      Thanks!
      --
      Scott K - 1994 850 Turbo








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    Vacuum Readings (Dipstick Smoke) 850 1994

    posted by  someone claiming to be gwen on  Tue Aug 4 15:04 CST 2009 [RELATED]

    With those kind of miles, your whole egr system could be clogging up.......

    Might be a good time to have your oil separator and all the lines that go to it replaced. Oil separator is under the intake manifold......








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      Vacuum Readings (Dipstick Smoke) 850 1994

      posted by  stkelly on  Thu Aug 6 11:48 CST 2009
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      I replaced the PCV system at 170K miles, while I was in there I also manually cleaned the EGR hole (which was clogged) and flushed the EGR itself. Maybe it clogged back up in ~35K miles... I'm hoping not, but if it's not that unusual for these cars I will look there next.

      Thanks!!
      --
      Scott K - 1994 850 Turbo








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    Vacuum Readings (Dipstick Smoke) 850 1994

    posted by  Tapsa on  Mon Aug 3 18:42 CST 2009
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    last visit: Sun Oct 19 13:29 CST 2014
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    Hi, I measure crank case pressure few times a year to follow pcv. typically get 13.6 psi which varies a little if pressing gas or lifting foot of the pedal.

    CC not working: if you have played with your battery then check the vacum line around it.

    br tapsa








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    Vacuum Readings (Dipstick Smoke) 850 1994

    posted by  KlausC on  Mon Aug 3 16:01 CST 2009
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    last visit: Fri Oct 24 10:15 CST 2014
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    You are in luck. The vacuum decreases when the AC is turned on because the idle air control is addin more air to the intake manifold. The lucky part? Clean the PCT nipple. Be careful, it is old plastic and fragile, located at the air intake just in front of the turbo. The vacuum line is plugged there. Use carb cleaner to get the nipple cleaned. It may take a thin piece of metal to help thing along. Use a flashlight to let you see better.

    Klaus
    --
    The more I learn, the more I forget. So why learn?








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      Vacuum Readings (Dipstick Smoke) 850 1994

      posted by  stkelly on  Mon Aug 3 17:01 CST 2009
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      last visit: Fri Aug 31 18:55 CST 2012
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      Thanks Klaus. I tried cleaning the small PCT nipple. I put the end of the carb cleaner in there and sprayed and nothing came back out at me. I also stuck a paper clip end in there and it came out clean. I also hooked up the vacuum meter to the hose that connects to the small PCT nipple and got vacuum so the hose leading to the PCT isn't clogged. I still get the same result as before, smoke with the A/C and a lower vacuum pressure. What pressure should I be at idle? Does it make sense to take off the larger connector on the PCT and clean it from there?

      Thanks!

      Scott
      --
      Scott K - 1994 850 Turbo








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        Vacuum Readings (Dipstick Smoke) 850 1994

        posted by  KlausC on  Tue Aug 4 04:37 CST 2009
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        last visit: Fri Oct 24 10:15 CST 2014
        [RELATED]

        Your vacuum numbers sound real good to me, on second thought. Perhaps you should give it a compression test with a warm engine and wide open throttle. It could be the valve guides are worn. Compression with a new engine is around 180 psi, a nicely broken in engine will probably be around 170 or so.

        As to the cruise control, it has its own vacuum system. The pump is attached to the bottom of the battery tray. Without removing the battery, you should be able to follow the plastic vacuum line that comes up from under to the firewall. I checked my 1998 by unplugging the line from the pump, just barely visible with the battery in place, and sucking on the line and watching the throttle cable move a little bit. If the cable does not move, suspect the switch above the brake pedal.

        Klaus
        --
        The more I learn, the more I forget. So why learn?







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