Edmunds Answers



  • docj 08/27/08 2:09 pm PST

    Sounds like you could have an open in circuit 120 or an open ground circuit.Possibly a faulty control module. or ...PCM???

    Start with this...
    Apply a fused 12v to fuel pump "test" terminal..listen for the in tank pump to operate...if no..
    Disconnect the chassis harness fuel pump connector.Connect a test light between ckt 120 and ground on chassis...Test light off,repair the open in circuit 120....test light on,connect test light ground to fuel pump ground circuit..test light on,replace fuel pump..test light off,repair open in fuel pump ground circuit.
    This is all for if the pump didnt run with the fused 12v to test terminal.
    Now,if the pump ran with fused 12v to test terminal....remove 12v from test terminal,ignition off for 10 seconds,then ignition on,listen for pump,pump should operate for 2 seconds after ignition on,if no...then...disconnect fuel pump relay,ignition on,engine stopped,probe relay harness connector terminal ckt 440 with a test light to ground...light off,repair open ckt 440...light on,connect a test light between harness connector terminal circuit 440 and relay ground circuit....light off,repair open in relay ground circuit..light on,connect test light between terminal 465 and ground,ignition off for 10 seconds...ignition on,test light should light for 2 seconds,if no..open or short to ground in circuit 465 or faulty control module connections or faulty control module...if yes...faulty connection at relay terminal A or faulty relay.
    The oil pressure switch usually takes over operation of the fuel pump if the fuel pump relay fails.And it will shut down the fuel if the oil pressure /level is too low.
    Engine should continue to run off the oil pressure switch if you remove the fuel relay while running.if it doesnt continue to run ,there could be an open in circuit 440 or 120 to the oil pressure switch or a faulty oil pressure switch.

    Hope this helps
    Let me know

    FYI..circuit 120 gray.. B12 at the PCM fuel pump signal
    .......circuit 465 dk grn/white tracer F6 at the PCM..fuel pump relay control
    .......circuit 440 orn E16 at the PCM.battery feed..
    .......curcuit 450 ground pump/relay

    Hope this isnt confusing to you

    Doc J
    Fuse #9 (ECM B) 15a

  • docj 08/27/08 2:59 pm PST

    I mentioned part of this before....
    Should the fuel pump relay or the 12 volt relay drive from the PCM fail,the fuel pump will receive current thru the oil pressure switch as a backup circuit.

    The fuel pump test terminal is located on the drivers side of the engine compartment.

    When the ignition is turned on,the control module will turn on the fuel pump.it will remain on as long as the engine is cranking or running and the PCM is receiving distributor reference pulses.If there are no pulses the PCM will shut off the fuel pump within 2 seconds after ignition on or engine stops.

    Doc J

  • docj 08/28/08 5:09 pm PST

    Justa question....

    Throttle body or CPI??

    Doc J

  • pinetopfirefig 10/05/08 1:29 pm PST

    I am having the same problem. No power to fuel pump. This is after the fuel pump went out and a new one installed. I was thinking bad ignition switch. Could this have caused the pump to go out initially?


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