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Air Pressure Aft Filter in WC -Man

Discussion in 'Engines' started by Marblehead01945, Oct 4, 2020.

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  1. Marblehead01945, Oct 4, 2020
    #1
    Marblehead01945

    Marblehead01945 Member

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    All,
    I just noticed something a little unusual. Man 2848 engines. I have a disparity between Port and Starboard engines (see photo) and I have no idea what the heck Air pressure Aft Filter in WC is or why we have this disparity and if i need to fix this and how. Everything seems to run normal but I am curious of what this is all about. Anyone have any idea?[​IMG]

    Attached Files:

  2. Capt Ralph, Oct 4, 2020
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    Dirty air filters.
    Air pressure after air filter. Not in PSI, maybe Bar. Should be a low number.
    before starting should be 0 or 1.
    There was another thread on this, try a search for more details.
    Strange readings may also include a bad connect at the sender or bad sender.

    Check your manuals for part numbers or call your MAN rep with serial numbers.
    Performance Diesel in Houston is my support and part shop.
  3. Capt Ralph, Oct 4, 2020
    #3
    Capt Ralph

    Capt Ralph Senior Member

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    Need to get your pictures under 800 pix wide also.
    Can you edit and get the sizes down?
  4. mapism, Oct 5, 2020
    #4
    mapism

    mapism Senior Member

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    Nah, can't be bar, for two reasons:
    1) in those display the choice between metric or imperial affects all parameters, so that's bound to be in PSI as anything else.
    2) 19 bar is an absurd value, which would surely trigger some alarm.

    But you are correct that it should be a low number.
    Can't tell by heart what the acceptable range is, maybe RTFM?
  5. Marblehead01945, Oct 5, 2020
    #5
    Marblehead01945

    Marblehead01945 Member

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    I just heard from my mechanic and he said- The -1 is correct at that rpm. I would say the port sensor is defective. That’s about a $700 sensor.

    The positive pressure reading won’t trigger any faults because positive pressure is good.
  6. Fiammetta42, Oct 5, 2020
    #6
    Fiammetta42

    Fiammetta42 Member

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    Mines in Mbar 60 in this vid , stop it @ 0.6 seconds .
    You can change the units and Language .


    about 3 years old , so next season I will change them , the Mbar gradually creeps up , 30 , 40 , now 60 , it’s the suction pressure so relates to the clogging of the paper element pours .
    Hrs wise I would say 200 to 250 thus far fwiw .But it’s not a time thing it’s a Mbar thing .
    100 Mbar as said above is considered they are done .
    Last edited: Oct 5, 2020
  7. Fiammetta42, Oct 5, 2020
    #7
    Fiammetta42

    Fiammetta42 Member

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  8. Marblehead01945, Oct 5, 2020
    #8
    Marblehead01945

    Marblehead01945 Member

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    looking back at the old thread that Capt Ralph spoke about earlier I think its the sensor not the filter. It doesn't make sense to me if the number is positive that it could be the filter.
  9. mapism, Oct 5, 2020
    #9
    mapism

    mapism Senior Member

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    Positive pressure actually isn't "good", it's a nonsense.
    I was in doubt about whether the MMDS display reading should show pressure (hence a negative number to be expected) or SUCTION (hence a positive number).
    In fact, if you look at the video posted by F42, his displays (which are the predecessors of yours) show SUCTION, with a positive number.
    In other words, they reversed the logic, over time.

    Anyhow, the bottom line is that you are probably right in thinking that port sensor is defective.
  10. mapism, Oct 5, 2020
    #10
    mapism

    mapism Senior Member

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    Yup, because you have the displays configured as metric: boost pressure is also in bar.
    The OP numbers, port sensor anomaly aside, can only be in PSI.
  11. Marblehead01945, Oct 5, 2020
    #11
    Marblehead01945

    Marblehead01945 Member

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    good catch- just to confirm- this is a 675.00 part without freight from another vendor I checked as well. joy....
  12. Capt Ralph, Oct 5, 2020
    #12
    Capt Ralph

    Capt Ralph Senior Member

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    Before you order the sensor;
    I remember on a 900CRM, the sender and wires stuck out a bit. Double check for damage here.
    Also, Can you swap between sides or engines and check where the error goes (or stays).

    Who is quoting $675?
  13. Marblehead01945, Oct 5, 2020
    #13
    Marblehead01945

    Marblehead01945 Member

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    Performance Diesel- nice folks, very helpful. I will swap them but to be honest I would not even know where to find this sensor. Somewhere attached to the air filter area I would imagine. Need to get the manual out to make sure I have the correct one.
  14. Capt Ralph, Oct 5, 2020
    #14
    Capt Ralph

    Capt Ralph Senior Member

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    That is THE shop to call.
    Yep, great folks in there.

    Ouch$$ ..

    There is a neck between the air filter and the turbo inlet. The only thing wired on this air tube is the sender.
  15. Marblehead01945, Oct 5, 2020
    #15
    Marblehead01945

    Marblehead01945 Member

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    awesome. Will get to that shortly. Thank you everyone for their help. Thats what makes this forum so great.
  16. Capt Ralph, Oct 5, 2020
    #16
    Capt Ralph

    Capt Ralph Senior Member

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    Please keep us updated.
    We like to watch...
  17. v10builder1, Oct 7, 2020
    #17
    v10builder1

    v10builder1 Senior Member

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    The unit of pressure in question is "inches of water column". This reading is an absolute pressure, we commonly refer to this as a vacuum. The 19 value means that if you connected a hose from the tap on the air line to the top of a vertical glass tube and placed the bottom of the tube in a glass of water, the "pressure" (actually vacuum) would pull the water 19 inches up into the tube.
  18. mapism, Oct 7, 2020
    #18
    mapism

    mapism Senior Member

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    Interesting, thanks.
    Every day is a school day, as the old saying goes!
  19. Capt Ralph, Oct 7, 2020
    #19
    Capt Ralph

    Capt Ralph Senior Member

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    Then the filter could be pretty well clogged up, or sensor not calibrated or bad.
    I would hate to think that air filter would be in that bad of shape.
  20. Marblehead01945, Oct 7, 2020
    #20
    Marblehead01945

    Marblehead01945 Member

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    definitely not the airfilter. They are both in great shape and replaced at the same time so thats hard to imagine. My mechanic says its positive air flow not negative so thats the reason not to worry and probably the sensor.
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