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BJ-74 Air Filter housing pressure ports

Discussion in '70-Series Tech' started by John Galt, Jul 17, 2017 at 2:11 AM.

  1. John Galt

    John Galt

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    The 13B-T Air Filter housing on the BJ-74 has pressure ports for measuring the pressure drop across the air filter.
    Can anyone post the service specifications on this pressure differential?
     
  2. stayalert

    stayalert SILVER Star

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    I just looked in my owners manual (1987 BJ74) (in Japanese) and couldn't find any picture of what you're describing....That's not to say there isn't a maintenance checkpoint/number in the tables in the back....Sorry....That's pretty much all i got....
     
  3. roscoFJ73

    roscoFJ73

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    Is it something to do with the blocked filter sensor?
     
  4. John Galt

    John Galt

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    My truck does not have a blocked filter sensor. Do you have more info on that optional equipment?
     
  5. roscoFJ73

    roscoFJ73

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    It works by sensing the amount of vacuum after the filter. As the filter gets blocked the vacuum increases. When the vacuum gets too much a diaphragm switches on the filter light . Ive heard the fliter has to be incredibly blocked for it to be activated.
    I'm not sure why it has 2 hoses, I guess its the difference in the vacuum before and after the filter that it measures.. This one is on a 12HT but the 7* series is almost identical except the 7* sits on top of the filter lid to save room.The petrol models also had it. On my FJ73 I think it sat on the side of the filter as above.
    I was told it was an Australia only option but I think some Middle East models might have had it.
    I should test it to see if it actually works. My filter light comes on when the ignition is turn so that is working. I think its using the same fliter light as the fuel filter when it senses water
    12HT pics 005.jpg
     
  6. stayalert

    stayalert SILVER Star

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    My '87 JDM BJ74 has the ports and "filter" light but ports are capped (part of water proofing? with snork?)

    "filter" indicator BJ74.jpg filter ports on air cleaner housing.jpg
     
  7. Mookies

    Mookies

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    FWIW that light is the water in the fuel filter warning...at least on my PZJ75. My air filter setup is the same, no sensor and all vac lines capped for the snorkel.
     
  8. stayalert

    stayalert SILVER Star

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    I was wondering if that was the case
     
  9. roscoFJ73

    roscoFJ73

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    I was told if you have the air filter sensor and the fuel filter sensor, they use the same warning light. There is lots of vacant plugs on the filter side, I guess one of them is for the air filter sensor if you don't have one