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1992 4.3L oil pressure switch location

Discussion in 'The Garage' started by R72K5, Jan 19, 2005.

  1. R72K5

    R72K5 Banned

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    ok got it figured out and got it to inject fuel out injectors and start and run and drive, finally,
    sop i have one more Q,


    in 1992 in the trucks on 4,3L TBI which is the oil pressure switch ? according to hanyes manual the oil press switch test is to unplug the fuel pump relay with engine running and if it dies then its bad OP switch, well it died when i unplugged the relay

    that sound accurate ?


    theres a three wire (long vertically mounted) cylindrical unit just behind intake- next to distributor-in the top of block,

    and i cant see anything down by oil filter on side of block anywhere like you usually see on the 5.0L and such,



    anyone know for sure where OP switch is located on 92 4.3?? with 700r4, TBI,
    VIN Z

    anyone got a parts TBI 4.3L with good OP switch, and ignition coil ?


    thanks
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    3 wire is going to be a combo oil pressure switch/sender for the oil pressure gauge and fuel pump.

    If you have a pinout of that switch (Echlin catalog at Napa should have a pinout for the switch/sender) you can probably just jumper the two wires for the oil pressure switch portion of it, and if it starts, I'd say the pressure switch IS the problem for certain.

    The test you ran makes sense to me...oil pressure switch is a backup in case the relay fails, so it's tied in somehow. With 5+ PSI of oil pressure (engine running in your case) the switch should keep the fuel pump running regardless if the relay fails, at least as I see it, and I would think unplugging the relay is a pretty good simulation of it failing.
     
  3. R72K5

    R72K5 Banned

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    thats what i figured too hehe, its obvious the truck is only running from relay then, and its not supposed to be closed circuit cept for priming pump for starting engine right ?

    my brother said he put in a 45psi pump

    but i told him the regulator on the TBI unit will override that and knock it down to max reuired PSI, set by factory adjustment

    so 9-13 PSI

    so OP switch is that one on top of engine next to distributor ?

    cool

    thanks
    :D
     
  4. 1979jimmy350

    1979jimmy350 1/2 ton status

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    i know on my truck there are two relays next to each other one is for the oil pressure and that is the one you use for the test not the fuel pump relay any car that has the fuel pump unpluged will die because the pump shuts off
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Yes, later setups were 3 wire, earlier stuff would have had a two wire switch, plus a seperate one wire sending unit for the gauge.
     
  6. R72K5

    R72K5 Banned

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    only one relay underhood in 92
    for fuel pump
    and thats all


    thanks
     
  7. R72K5

    R72K5 Banned

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    agreed

    :D

    thanks
     

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