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Bypassing Oil Pressure Switch?

Discussion in 'Electrical Wiring / Questions' started by ~Slideways~, Mar 24, 2009.

  1. ~Slideways~

    ~Slideways~ New Member

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    Is it possible to bridge a couple of wires for the OPS to bypass it? Basically to trick it into thinking there is oil pressure (there is pressure by the way!).

    If so, which wires?

    Thanks.
     
  2. delcowizzid

    delcowizzid on holiday

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    i dont know why you want to do this as it will stop the light coming on if there is no pressure but just cut the little blue wire at the pressure switch im sure its blue its the skinny one not the fat wires that will stop the light going
     
  3. ~Slideways~

    ~Slideways~ New Member

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    Nah its not for the light (I dont have one) its because they keep failing on me and cutting the fuel pump. I've been through 4 second hand ones over less than a year and just recently a brand new one from Repco... which failed after a couple of months, just few hundred km's!

    Most recently it just stopped working, no oil leak onto the plug, no blown EFI fuse and fuel pump didn't even get the tell tale sign of running-on after turning off the ign. It just stopped working.

    So Im looking into the possibility of re wiring it to run no OPS.

    There is very little chance of running no oil since I change it more often than normal and it takes almost 8litres (modified sump).
     
  4. delcowizzid

    delcowizzid on holiday

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    just pull the plug off it then its only a backup fuel pump supply anyway pump will run without it.
     
  5. Not_An_Abba_Fan

    Not_An_Abba_Fan Exhaust Guru

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    You didn't use silicone on the sump gasket did you? Possibly the OPS is getting contaminated, that is why it is failing.
     
  6. ~Slideways~

    ~Slideways~ New Member

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    Even on start up? Cause mine refused to start until I changed the OPS. Maybe its not wired to the pump correctly?
     
  7. delcowizzid

    delcowizzid on holiday

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    ide say you have other issues if it doesnt prime before starting the oil pressure switch only gets used as a backup when the normal fuel pump circuit fails.should prime on startup with op switch connected.as the oil pressure switch only turns pump on when there is oil pressure thats why they keep going when you turn the engine off will run till the oil pressure in the engine drops
     
  8. Cheap6

    Cheap6 New Member

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    The fuel pump relay will remain switched by the ECM for 2 seconds after the engine stops running too. (the relay and the oil pressure switch provide power to the pump in parallel; either alone will run the pump.)

    A failed fuel pump relay would be one possible fault. Swapping the relay with one known to be good would be an easy first step. Step two would be to check that the switching circuit for the relay, of which the ECM is a part, is working and that there is power to the switched side of the relay.

    They are easy checks. If they are OK, maybe check to see if there is power to and earth from the fuel pump at the external connnector at the tank when the ignition is first switched on and work from there.
     
  9. forkdriver1

    forkdriver1 New Member

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    huge flat spot

    hi to all
    I have a vn wagon, v6 5 speed which has had lots of problems, and this one is a beauty.

    the car drives normal when cold but once warm will not accelorate more than is required to keep it going, feels like a fuel bloke or vacuum problem, total lack of power yet does no stall.
    recent repairs include throttle body clean/ great km to the ltr ( 10.5) crank cse sensor replaced, fuel pump and tank new, filter and injector O' rings replaced, also plugs leads and coil pak,( updated to vr)
    still the bugger has this flat spot.
    any or all help greatly appreciated, regards ken.
     
  10. VRcommondoor

    VRcommondoor New Member

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    fuel pump not working, and ign. fuse blowing every start.

    Hi all. I have a stock VR 3.8 with dual fuel. Recently my fuel pump stopped working. At the same time I was unable to even start with gas. I found the ignition fuse had blown, replaced it and presto, started (on gas). The fuse still blows every time i start the car and the fuel pump is not working. Some one mentioned to me to check the oil pressure switch? Is this necessary? Any ideas or suggestions are appreciated.
    Cheers
     

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