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Lock Out Valve Failure {Contour}

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  • Lock Out Valve Failure {Contour}

    The CNG tank lock out valve has failed on my 2000 Ford Contour. The symptom was that the car would start on CNG, run for less than one minute, during which time the CNG pressure would drop rapidly and then the car switches over to gasoline, even though the CNG tank is full. I knew that there had to be a restriction in the fuel line.

    I have done some troubleshooting. When I supply CNG from another tank, the car runs fine. The lock out valve receives 12 VDC when the key is turned on but the valve no longer clicks indicating proper operation, and no gas flows out of the tank. I removed the coil and it is magnetized when 12 VDC is supplied, but very weakly. I have now removed the tank from the vehicle.

    I have a couple of questions:

    1. How can I safely bleed off the tank pressure, in order to work on or replace the lock off valve?

    2. Does anyone have a source of replacement valves, coils, etc. for the Contour? It is a GFI system.

    I hope some of you can give me some advice.

    Thanks,

    Curt

  • #2
    Re: Lock Out Valve Failure {Contour}

    Originally posted by cchildr View Post
    The CNG tank lock out valve has failed on my 2000 Ford Contour. The symptom was that the car would start on CNG, run for less than one minute, during which time the CNG pressure would drop rapidly and then the car switches over to gasoline, even though the CNG tank is full. I knew that there had to be a restriction in the fuel line.

    I have done some troubleshooting. When I supply CNG from another tank, the car runs fine. The lock out valve receives 12 VDC when the key is turned on but the valve no longer clicks indicating proper operation, and no gas flows out of the tank. I removed the coil and it is magnetized when 12 VDC is supplied, but very weakly. I have now removed the tank from the vehicle.

    I have a couple of questions:

    1. How can I safely bleed off the tank pressure, in order to work on or replace the lock off valve?

    2. Does anyone have a source of replacement valves, coils, etc. for the Contour? It is a GFI system.

    I hope some of you can give me some advice.

    Thanks,

    Curt

    Hi Curt;

    The best advice I can give is have someone with experience defueling (venting) tanks do the Job. I haven't played with that type of valve, but GIF has a manual overide so you can open the tank manually for venting.

    You need to first of all ground the tank to a good earth ground to prevent static build up and possible fire. You can use good jumper cables to do the job. If you can find the electrical ground for a building (a copper rod that is driven into the ground (earth) use that is what you want. The tank, vent line and vent stack need to have an electrical connect to ground.

    Don't remove the tank from the vehicle when it is pressurized! If you drop a pressurized tank and it knocks the valve off -- you have an unguided missle and somebody could get hirt.

    Next you need attach some type of heavy duty hose or stainless steel line, that will take about 5,000 psi pressure, to the tank outlet to get the gas discharge away from the vehicle. We usually a vent stack that is made of 2 inch schedule gas pipe that meets the requirements of NFPA 52.

    You need to have some way control the gas discharge from the tank so that it does not get too cold from the press drop. If valve on the tanks starts frosting slow down the gas flow. It will probably take about 20 minutes to dump the tank safely.

    When the tank is empty (I am assuming that the tank is not a type 4 all composit tank --some different rules apply) then you can safely remove the tank from the vehicle and get the valve repaired or placed. Cover the end of the tank. You do not want to get air into the tank -- it could possibly get a combustable mixture in the tank (that is not a good thing). If it sit open for while, it will need to be purged with nitrogen or some other inert gas.

    If you get a new tank valve you also need to get a new PRD (pressure relief device). Under NFPA 52 you can not move a PRD from one valve to another valve.

    Again you are better off to have someone that has been trained in cylinder defueling do the job.

    Be Careful

    Larrycng

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    • #3
      Re: Lock Out Valve Failure {Contour}

      I have the same problem, no click at the solenoid tank valve, can a manual valve be installed to eliminate dirty unfiltered cng from clogging another solenoid valve? anybody...thanks

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