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Spooky CNG fillup. CNG leaking from filler nozzle

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  • GreenMM
    started a topic Spooky CNG fillup. CNG leaking from filler nozzle

    Spooky CNG fillup. CNG leaking from filler nozzle

    I filled up my 3000 psi vehicle Thursday and there was a stronger than normal CNG smell in the air.
    When I disconnected the filler when it was full like normal I heard a lot of air pressure releasing (fuel)!
    I sort of panicked. It's Never done this before. I thought it was the pump end and was feeling with my fingers but then realized it was my vehicle side leaking. I sort of pressed around my filler nozzle area and the pressure got lighter and lighter and stopped.
    So I started thinking maybe my fill neck's valve is stuck open.
    Maybe it only had like 100-120 psi and leaked that all out to atmosphere?
    Is there a secondary safety valve where the 3000 psi is safely kept behind?
    I checked minutes later and no gas pressure was releasing and also checked an hour later on drive.
    I drove 70 miles on indicated 1/4 tank so tanks arent venting.
    What next?
    will it leak again? Is this really dangerous? Can I replace the fill valve or lubricate it so it doesn't stick open?
    I was pretty scared by that happening suddenly.
    I had filled it up about 6 weeks ago and every fill up before it never did this.
    Last edited by GreenMM; 10-14-2017, 11:04 PM.

  • GreenMM
    replied
    I just sold the van last night. Very happy with the price. Happy buyer.
    Unlike last time around (for me) I fully and completely informed buyer about tanks being expired and what that really means.
    I drove to CNG station with him last night and showed him how to fill it
    It filled up normally, perfectly, not like the very last time I filled it up October 2017 and posted about it here - and the escaping CNG after I disconnected the nozzle.

    Leave a comment:


  • GreenMM
    replied
    Attached Files

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  • GreenMM
    replied
    Here's pics of the CNG fill up nozzle underneath vehicle and above. I have not done any repairs to this area since the 'spooky'' fill up October 2017. I have not filled it since then and it's only driven about 4 miles since I parked it after the radiator blew a hole in it.
    The rubber cap on the nozzle seems to say "Staubli". Is that a brand of the valve? Maybe it's this 'receptacle' here?:
    https://www.staubli.com/en-us/connec...v-vehicle-gmv/
    On the underneath picture - what's the gold colored protrusion? A relief valve? A anti leak valve?
    O ring close up. I can see it near the surface of the nozzle. Is that normal? "Staubil" appears to be written on the cap.
    Last edited by GreenMM; 08-08-2018, 10:33 AM.

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  • GreenMM
    replied
    Ah, this is very interesting, and sounds like careful smart engineering design work. This helps allay my fears of a full throttle release of 3000 psi due to a bad filler O ring or valve.

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  • cnghal
    replied
    Yes, the factory solenoid valves act as a check valve when fueling. They also act as a flow restrictor. By only having so much power to the plunger, they won't always open into a leaked down, or open system. The pressure in the tank holds it closed until, or unless there is back pressure in the system.

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  • GreenMM
    replied
    Good point. So with no voltage to the tank valves themselves, they will stay shut - except for obviously somehow functioning as a one way only fill IN valve.

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  • next2pool
    replied
    It is very important to shut off the ignition when refueling to make sure the tank solenoids are closed. If you have a leaking O-Ring or a check valve failure, you will vent the pressure between the tanks and filler but nothing within the tanks (assuming the solenoids are working)

    Leave a comment:


  • GreenMM
    replied
    OK cool! Thanks, will check it out. Thank you again

    Leave a comment:


  • Amfuel
    replied
    No, when looking into the end of the receptacle you will see the black Oring - unless it is missing. Occasionally the public fueling nozzle will pull the Oring out when disconnecting if the fast fill nozzle is damaged a bit. If you don't see the Oring, look close and you will see the groove it fits into.

    Leave a comment:


  • GreenMM
    replied
    Do you have to have the system de- pressurized to do that?
    If so, would that be: unplug all 3 wires to valves (I have 3 factory tanks), run the engine until it dies, then let out the pressure slowly around the coalescent filter?
    Also, I've never cleaned that, perhaps that might be a good time to do that as well (?). I've had this van 2 years, but only gone about 3000-4000 miles on it so far.

    I also saw that local Walmart has CRC silicone based spray lube for $3. That should be okay to keep the o ring properly lubed by spraying filler nozzle each fill up to get silicon into the O Ring?

    Thanks!

    Leave a comment:


  • Amfuel
    replied
    Yes, very easy. just pick the Oring out of the receptacle with a point or a small screw driver or similar. Be careful that you don't scratch the metal. Pop a new one in the groove. If it doesn't want to go in, lube it a little. Non- petroleum based lube.

    Leave a comment:


  • GreenMM
    replied
    Was the swap of the O ring easy to do?

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  • CNG F-150
    replied
    ya I went to honda and got the o-ring...had to swap it twice on 2 cars IIRC because the gas will leak as it's filling...scary stuff!

    Leave a comment:


  • GreenMM
    replied
    I read a few posts searching now on my laptop.
    Can I get an inexpensive Bunin or whatever that strong material is O ring and install a new one?
    How is that done, with fuel still in the system?

    And CNGhal, you had 3600 psi attack you?? Did that all vent out through the nozzle??
    Can that stuff ignite when mixed with oxygen at either the high or very low pressure range?

    Leave a comment:

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