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Need an Auxilary Air Valve for 308QV

Discussion in 'Technical Q&A' started by kdross, Feb 23, 2004.

  1. kdross

    kdross Formula Junior
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    Feb 10, 2002
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    Does anyone know where I can get an Auxilary Air Valve for my 308QV or the Bosch part number? I called two dealers and the usual after market guys and the best price I got was $305.00 USA. I am sure that this is a $100 part from a VW or BMW, but I cannot locate any part numbers.

    Thanks.
    Ken
     
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  3. Steve Magnusson

    Steve Magnusson F1 World Champ
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    What led you to this conclusion?

    Is the 10-digit Bosch PN not marked somewhere on the outside of the AAV?
     
  4. BigTex

    BigTex Seven Time F1 World Champ
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    My gf's new Turbo Beetle doesn't have any $100 parts on it!

    Well, the dash flower vase is $34, that's the ONLY one! LOL
     
  5. kdross

    kdross Formula Junior
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    I just removed the part and now have the Bosch part #. Thanks.

    Ken
     
  6. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Ken -- Please post the Bosch PN here so it gets saved for others...
     
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  8. kdross

    kdross Formula Junior
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    Steve:

    I removed the Aux air valve from the car and there was a small opening inside (about a 1/3 of a moon). This was at 50 degrees F. I then put the AAV in the freeezer and the opening remained the same size. I then put the unit in the oven at 200 degrees F (after waiting about 30 minutes so that the metal and electrical components would not go from one extreme to another) and the opening slowly got a little smaller, but still remained open. Based on your post in my previous thread, it appears that the unit is not working properly. Please correct me if I am incorrect.

    One question I have is why would the car idle at 1,000 rpm and not 2,500 rpm if the AAV is open a little. I thought that the AAV would have to be open (which it is) for the idle to remain high. I would think the car should idle high with the current small opening of the AAV.

    What is my next step? Is there a way to test the unit in the car and to verify if the AAV is working properly? Should I attempt to clean the unit with WD-40 or a carb cleaner?

    The Bosch part number for the Auxilary Air Valve is 0 280 140 229

    Thanks.
    Ken
     
  9. 308GTS

    308GTS Formula 3

    Dec 27, 2001
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    Of course attempt to clean it. $305 or possibilty of cleaning it? I would try to clean it especially if it is dirty inside. It is common for the AAV to get stuck. Unless you just want a new one in there cleaning usually works.
     
  10. kdross

    kdross Formula Junior
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    What is the best way to clean the unit? I do not want to damage the electronics. Should I just spray WD-40 or Carb. cleaner, and if so, where do I spray?

    Thanks.
    Ken
     
  11. f355spider

    f355spider F1 World Champ
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    Ken,
    There are no delicate electronics in that thing, it is simply a bimetalic strip or spring. Try flushing it out with carb cleaner from each end, then spray a bit of WD40 and see what happens.

    Here is an explaination of what that is:
    http://www.auto-solve.com/mech_inj.htm#MFI12

    Try running that Bosch part number here:
    http://www.importeccatalog.com/ if it commonly fits on another car they will have it. If not, order from Ferrari UK.

    Dave
     
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  13. Gianluca

    Gianluca Formula Junior

    May 6, 2003
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    Ken,
    I just finished working on my AAV. Same symptoms like yours.
    I sprayed inside some Liquid Wrench and with a bamboo skewer I "excercised" the little metal shield that opens and closes. Spray a bit, excercise a bit.
    It seems to work well now. In the freezer it opens to more than half and plugged to a 12 V power supply it closes completely.
    As Dave said, it should not be very complicated inside and probably is just a little stuck.
    Good luck,

    Gianluca
     
  14. kdross

    kdross Formula Junior
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    Thanks guys. Here is a silly question. What what happen if I start the car with the Aux air valve off and the two hoses that normally connect the AVV unconnected. Shouldn't this reproduce a working AAV? I would think that my car should immediately idle at 2,500.

    Ken
     
  15. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Ken -- Having the AAV lines completely open to atmosphere is probably more extra air flow than a fully open AAV (but you'd need to try this with things "cold" so that the maximum extra fuel is also added).

    If you had an AAV that was stuck fully closed, you could just pop in a new one and things should be fine. Since you indicate that at "warm" conditions the old AAV is partially open, yet the engine is still at 1000 RPM, I'd have to conclude (as you implied) that someone tweaked the air bypass screw to compensate for your partially-open warm AAV. If you put a new AAV on, and the warm idle RPM is a little lowish, I think you could just open the air bypass screw a bit.

    Like Gianluca mentioned, the AAVs on my KE-Jet system have an internal +12V electrical heater -- does your version AAV have any electrical connections, or is it just heated from external sources?
     
  16. kdross

    kdross Formula Junior
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    Steve:

    I ran the test again and the AAV is about 1/4 open at room temp and in the freezer. The hole does not change size. When I put it in the oven at 200 F, the hole closes completely after about 10-15 minutes. I do have an electrical connection on the AAV, but I was not able to get a reading of any current from the plug (I had the key on all the way without starting the engine). Shouldn't I have 12V at this plug? Now I do not know whether the AVV is not working properly, if I do not have current going to the AAV, or both. I will post a picture of the AAV shortly.

    I tried cleaning the AAV with WD-40, but it did not seem to help the situation. Unfortunately, I did not have any carb cleaner in the basement.

    Ken
     
  17. Steve Magnusson

    Steve Magnusson F1 World Champ
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    I think the AAV +12V power comes from the same "protection" relay running the injection system so the engine would have to actually be running (or the starter motor cranking) to measure +12V at the AAV wiring (i.e., needs more than just ignition key "on").

    Since you're now indicating a definite difference in the AAV opening for room temp vs warm, I'd think you'd see an idle speed difference in room temp start-up vs warm (that's one of the problems dealing with these gizmos -- now that you've molested it a bit it may be behaving differently/better ;)).
     
  18. kdross

    kdross Formula Junior
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    Here is a picture of my AAV. As you can see, the unit has a plug for a 12v power supply. The size of the opening appears to be very small, and this is when the AAV came right out of the freezer. The opening is the same size at room temp.
     
  19. kdross

    kdross Formula Junior
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    Steve:

    Remember my original problem - the car idles at 1000 rpm for the first 60 seconds when cold, and then goes down to 500 rpm for the next 10 minutes, and then back to a normal idle of 1000 rpm. Based on the results of testing the AAV (small opening that does not change size when in the freezer or at room temp, and fully closed when in the oven at 200F), these results seem to correspond with the way the AAV is opening and closing.

    I would think that if the AAV would fully open then my idle would be at 2500 rpm or so.

    Ken
     
  20. Steve Magnusson

    Steve Magnusson F1 World Champ
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    I thought the +12V heater power is supplied continuously to the AAV with the engine running (not just when cold) so the "...then back..." part of that behavior sequence doesn't fit well with an AAV that goes from some amount open when cold to fully closed when warm in a continuous way -- but I'm not 100% sure about that.

    The mechanical advantage of the bending element + linkage isn't that great so I'm not sure that they ever go fully open, but no change in the vane position from RT to ~20 deg F is a little odd (although the amount of openness you show doesn't seem bad for RT IME).

    You're on the right track. Now that you've got a better understanding of the device try some tests -- e.g., 1) disassembled, you can just use your thumb/finger/cardboard to act as the "valve" on the hose end feeding extra air into the intake tract; 2) assembled, pinch one of the air hoses closed when idling warm. If the AAV itself is properly closed warm, your adding a second blockage should have no effect idle RPM; 3) your thought about confirming the AAV heating current is good (or voltage at the plug and DC resistance/continuity of the coil), etc..

    If you did test #1 (with you providing the "manual" extra air flow control) and it still exhibited the 1K RPM cold light-off drooping to 500 RPM behavior -- then I'd start looking elsewhere.

    If test #1 shows good behavior -- then you got the right gizmo.
     
  21. miked

    miked Formula Junior

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    I have been able to clean a couple of those with carb cleaner on my Audis when they were stuck. As Steve said, make sure that the 12v supply works as it should before condeming the AAV. Your photo looks like a typical VW/Audi AAV. VW part #'s for AAV are generally 0-280-140-XXX depending on the application which may vary by the temp/reaction curve of the bi-metalic strip. Any good parts house that specializes in VW should be able to match it or at least supply one that will work for you at a price under $100.

    Here is another good K Jetronic link, the AAV is under "part 2".
    http://www.volvoclub.org.uk/tech/fuel_injection/k_jetronic.htm

    some more links:
    http://www.users.bigpond.com/INTERJECT/KSITEPLN.HTM

    http://www.hdrogers.com/
    sometimes they have parts a lot cheaper than the "usual aftermarket guys"
     
  22. Mark 328

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    #19 Mark 328, Feb 25, 2004
    Last edited by a moderator: Sep 7, 2017
  23. kdross

    kdross Formula Junior
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    Thanks for the help guys. I will be testing the AAV on my car this weekend, but it appears to be working correctly. Assuming that the AAV is working, what else could cause a low idle on a cold start? I just got the book "Bosch Fuel Injection & Engine Management" by Charles O, Probst and will read it Friday night. I am determined to resolve my cold start problem, then I can resolve my hot start problem. :) It is always something.

    Ken
     
  24. jwise

    jwise Formula Junior

    Apr 2, 2003
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    Tha AAV on my euro 308 QV is the same as the BMW one pictured above-same exact part# 0 280 140 104. Weird. It seems to work fine. I took it off about a month ago and checked it. It's mounted under the expansion tank.
    FWIW
     
  25. f355spider

    f355spider F1 World Champ
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    Ken,
    Have you completed the testing as suggested by Steve Magnusson? I'm asking, because by the looks of your AAV, it does not appear to be opening enough when cold. The two that I have replaced in the past (VW and Nissan); the new replacements opened at least 3/4 of the way when removed from a freezer....

    Dave
     
  26. Gianluca

    Gianluca Formula Junior

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    Nice pictures, Mark.

    Do you know what model/year the BMW you took the AAV from was?
     

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