need help 1.testing EGR Back Pressure Transducer and 2.removing egr pipe at exhaust end! 3. removing egr gasket

finally decided to tackle the diagnosis, remove, clean and reinstall of the egr system components on my 1992 isuzu trooper 3.2L v6 automatic.

mostly it's much easier than i thought reading about other models and years. the egr seems to test out ok (i could see the valve piston move with engine-running tests and with the vacuum-pump tests, but it seemed to move lots less running than with the vacuum pump)...so, i removed it, it seemed very clean . . .but. . .

  1. testing the Back Pressure Transducer and how does it work ?

    i have the helm factory manual. the tests are to...
    Quote
    1. Remove vacuum hoses (3) from modulator.
    2. Place finger over back pressure transducer tube ôVSVö and blow in the tube ôEGRVö. Air should pass through filter part of BPT.
    3. Connect vacuum pump to "VSV" and plug tube "EGRV".
    4. Blow air into Tube "S". Should be able to obtain vacuum on pump.
    5. If EGR modulator fails this test, replace back pressure transducer.

    well, mine passed test (2.), but failed test (3.). okà but i can't figure out how vacuum could be created doing this test. i can get a slight vacuum by sucking air out of Tube "S", which makes more sense to me.

    does anybody know? is the book wrong? while i've read and understand the concept of the BPT i don't quite get how it works, exactly (inside there). or maybe iÆm not really understanding the concept. Any help?

    [Linked Image]

    [Linked Image]
    Here are 2 photos. TheöVSVö connection gets vacuum from the Vacuum Switching Valve. The ôEGRVö connection (with the red vacuum hose) passes vacuum to the EGR Valve. The ôSö connection, which is on the bottom of the BPT, gets the exhaust pressure from the EGR Valve.
  2. egr PIPE nut removal at exhaust end
    removing the 22mm nut at the EGR valve itself was very easy (i guess other models have cramped quarters). but at the exhaust end: there are two fasteners; the lower of the two is a bolt and was only a little difficult to loosen.
    the upper of the two is a nut on a stud and it's a bear and has resisted so far all attempts and i'm starting to round the nut off <img src="/forums/images/graemlins/confused.gif" alt="" />. help.
    access is through the driver's side wheel well. so far i've used powerblaster and a combination of a half-inch ratchet and socket and muscle; and a 12mm box wrench assisted by a piece of pipe for leverage. and i'm about to try heat. any other ideas for this nut in particular?

    another egr pipe possibility?if i can't get this nut off, i'm thinking i'll use 'wire cable' attached to an electric drill and rotor rooter it. does that sound OK? Or am i asking for trouble if i dislodge some stuff.

    i'm really thinking the pipe isn't clogged much if at all, but i've got everything else off and i'd like to make sure there is no restriction.


  3. egr gasket removal. is there a secret way to remove this easily? or is it just spray, scrape and cuss?


    thanks

    //bc

Last edited by trooperbc; 10/01/06 07:11 PM.