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2002 Civic GX High pressure regulator issues

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  • 2002 Civic GX High pressure regulator issues

    I have a 2002 Honda Civic GX that I believe I am having problems with the high pressure regulator. The problem started about a year ago with the gas light coming on and the fuel gauge going to empty. The car would still run though. I was initially able to reset this by disconnecting the battery cable and reattaching it after 10 seconds. The problem got worse when the car would not run and disconnecting the battery would not reset the gas light and gas gauge. I went through the factory service manual and did all the troubleshooting for the light. I found that I could reset the light and get the car to run if I bypassed the fuel pressure regulator switch by unplugging the wire that plugs into it and sticking a jumper wire in it effectively just connecting the two wire together. The car ran fine like this. I ordered a new fuel pressure regulator switch and took my time replacing it. When I put the new one in I found that my problem with the blinking gas light came back. I then bypassed the switch again. Yesterday I was driving the car and heard a hissing noise and started to smell natural gas. I stopped the car and shut it off. The gas stopped leaking. I found that the low pressure fuel filter had blown the oring out. I think what has happened is the high pressure regulator allowed too much pressure to flow past it to the low pressure side and thereby blew out the low pressure filter oring. The part that I do not understand is that in the factory manual it seems to indicate that the fuel pressure regulator switch will make the gas light flash and put the gas gauge at empty when there is a gas leak. This would seem to indicate the fuel pressure regulator switch would be in the normally open position when there is no gas pressure to it. However when I bench test the switch with an ohm meter I find that the switch is in the normally closed position with no pressure behind it (zero ohms between its two terminals). This would seem to indicate that the switch would actually go to a open position between the contacts when there is excessive pressure behind it and thus shutting the car off (thus removing my jumper wire).
    My questions are -

    1. Does anyone know for sure what the fuel pressure regulator switch is supposed to do?

    2. From what I can tell there is no repair parts available for the pressure regulator. Has anyone taken one of these apart? Maybe it has some derbies in it and a good cleaning might fix the problem.

    3. Are there any repair shops that could repair it?

    4. Could one use an aftermarket pressure regulator to replace the Honda one?

    5. What PSI is it supposed to operate with? 3600 psi to 150 psi? The low pressure regulator say not to exceed 193 psi.


  • #2
    Re: 2002 Civic GX High pressure regulator issues

    Based on this thread and the other recent high pressure regulator problem thread I think the empty fuel light is a safety feature. It is meant to shut off fuel in case the pressure in the tank is too high, usually right after a refuel with PSI > 3600.

    You may want to try prematurely ending the refuel once you hit a certain percentage or PSI fill to prevent the pump from overfilling your tank.

    The problem is not the switch. The switch is acting the way it's supposed to.

    When you bypassed it the high pressures inside the tank were allowed to make it pass the 3600>150 regulator and blow your O-ring out.

    The problem might be popping up on the 2nd gen GXs now because the fuel tank pressure sensors and or the fuel tank temperature sensors are starting to wear out and not accurately sensing the pressure in the tank. I do not have a shop manual so I can not give you advice on how to test those sensors. You may want to look in your manual to see how it's done.

    It will take some diagnosing to get to the root of the problem. As you mentioned it could be a faulty regulator but it sounds like the problem is upstream from there... which is the high pressure switch being bypassed by you.
    Last edited by themoneymultiplier; 04-08-2013, 11:11 AM.


    • #3
      Re: 2002 Civic GX High pressure regulator issues

      Check out my thread
      make sure you have warm coolant flowing through the high pressure reglator.
      I found the super cooled cng flowed through the high pressre reglator and the expanded when warmed and caused all the symptoms you described.
      I figured this out after I changed out a perfectly good high pressure regulator and pressure switch.
      Last edited by Abe; 04-08-2013, 12:19 PM.


      • #4
        Attached Files


        • #5
          I have a friend who was having the exact same issue with the filter blowing out. I showed him Abe's great post (link above), and his problem was solved. The thermo valve appears to operate like a very small radiator thermostat.