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  • Cavalier Won't Take Fuel

    I have a 2002 cavalier and a FMQ2-3600. The pump runs for 20 seconds, builds pressure ( by the sound of the pump) and shuts down and relieves pressure. When I remove the brass manual shut of valve on the tank the pump will run forever. Counter clockwise opens the valve, I open the valve reinstall and the pump runs for 20 sec. What am I missing? Why won't the tank fill? Thank you, Hooper

  • #2
    Re: Cavalier Won't Take Fuel

    What brass manual valve on the tank are you talking about? You aren't opening the tank vent are you?

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    • #3
      Re: Cavalier Won't Take Fuel

      Are you sure that the CNG tank in the car isn't already full? And that the tank valve is sticking not allowing you to run on CNG?
      sigpichttp://WWW.CNGMOTORS.COM
      SAVE TIME. SAVE MONEY. SAVE THE ENVIRONMENT.

      2003 Hummer H2 bi-fuel
      2000 GMC Yukon XL bi-fuel
      1999 International 4700 dual-fuel
      2007 Chevy Avalanche bi-fuel

      FMQ2-36 Fuelmaker w/ 24 GGE cascade

      Comment


      • #4
        Re: Cavalier Won't Take Fuel

        Murphy has a point that the tank might be full. However, it sounds like you also have opened the tank vent ("brass manual shutoff valve on the tank"). This would vent the tank regardless of the operation of the high pressure lockoff valve. A couple of questions---Do you have a commercial fuel station to fill at? Are you able to fill OK when using one? When you turn on the ignition, is the red light on the fuel switch on? If not, what does the fuel gauge read? If the light is on, what does the fuel gauge read if you hold the switch down for several seconds? The gauge will indicate if you have any pressure in the tank. (assuming the pressure transducer is working) Does the fuelmaker shut down with a "full tank" indication (solid yellow light)? After the fuelmaker shuts down, turn on the ignition--do you hear the "ping" from the HPL solenoid valve in the tank? Does the car try to start on CNG and then change over to gasoline? A final check to make sure that the fuelmaker is working and there is nothing blocking the fill port, lines to the HPL, or lines to the high pressure regulator is to do the following: In a well vented area, loosen (but don't remove) the tubenut on the fuel line located at the rear of the low pressure lockout solenoid valve. This valve is located under the hood on top of the engine and supplies fuel to the low pressure regulator. Let any fuel in the lines vent---this should take a few seconds. Connect and start the fuelmaker. If you hear gas leaking from the loosened tubenut, everything is in order--shut off the fuelmaker. If not, you have an obstruction in the system unrelated to the high pressure lockout valve. You must leak check the tubenut with a soapy water solution after re-tightening the nut and repressurizing the line with the fuelmaker. If gas leaked out of the line with the fuelmaker attached, depending on how the fuel gauge reacted when you checked it, you either have a bad pressure transducer or a stuck lockout valve. This is just my uneducated opinion I hope it helps track down what's going on.

        Comment


        • #5
          Re: Cavalier Won't Take Fuel

          Guys, Let me be honest, I live in Waterford PA. NW corner of the state there is not a CNG car within 100 hundred miles of me. (I'm sure with that statement I'll find some) and the closest fuel is in Canada 120 miles away. I got my fuelmaker used on Ebay and the car from a dealer near Philly, it's a 2002 gov't car factory installed cng. I am going to make cng work, I drilled a gas well after work on my property. It's 10 years old and still has 500 lbs.on it. The fuel maker was tested before a got it so, I'll figure it works. The dealer did not use it on cng. Working from the male P36 that check valve works, next the fill line check valve works, I have pressure to this point. When I turn on the fuelmaker it runs for 20 sec. and shuts down. When I remove the high pressure lock-off manual shut-off fitting (brass fitting with the brass allen screw) and turn on the pump it will run all day, just blowing gas in the air. When you take a mirror and look in that port it looks like at that point the tank should take gas. What is keeping the tank from filling? When I remove that shut off fitting the tank can not have gas in it, is this correct? Thank you, Hooper I've used lots of o'rings bleeding things down.

          Comment


          • #6
            Re: Cavalier Won't Take Fuel

            Originally posted by siai47 View Post
            Murphy has a point that the tank might be full. However, it sounds like you also have opened the tank vent ("brass manual shutoff valve on the tank"). This would vent the tank regardless of the operation of the high pressure lockoff valve. A couple of questions---Do you have a commercial fuel station to fill at? Are you able to fill OK when using one? When you turn on the ignition, is the red light on the fuel switch on? If not, what does the fuel gauge read? If the light is on, what does the fuel gauge read if you hold the switch down for several seconds? The gauge will indicate if you have any pressure in the tank. (assuming the pressure transducer is working) Does the fuelmaker shut down with a "full tank" indication (solid yellow light)? After the fuelmaker shuts down, turn on the ignition--do you hear the "ping" from the HPL solenoid valve in the tank? Does the car try to start on CNG and then change over to gasoline? A final check to make sure that the fuelmaker is working and there is nothing blocking the fill port, lines to the HPL, or lines to the high pressure regulator is to do the following: In a well vented area, loosen (but don't remove) the tubenut on the fuel line located at the rear of the low pressure lockout solenoid valve. This valve is located under the hood on top of the engine and supplies fuel to the low pressure regulator. Let any fuel in the lines vent---this should take a few seconds. Connect and start the fuelmaker. If you hear gas leaking from the loosened tubenut, everything is in order--shut off the fuelmaker. If not, you have an obstruction in the system unrelated to the high pressure lockout valve. You must leak check the tubenut with a soapy water solution after re-tightening the nut and repressurizing the line with the fuelmaker. If gas leaked out of the line with the fuelmaker attached, depending on how the fuel gauge reacted when you checked it, you either have a bad pressure transducer or a stuck lockout valve. This is just my uneducated opinion I hope it helps track down what's going on.
            How can i know if my car is running with CNG?
            I totally fill up the CNG tank ,but i noticed after using the car 100 miles, that the gas gauge was going down .
            I have no light on on the switch either .
            how to check it out and what can be wrong ?
            Thanks all.

            Comment


            • #7
              Re: Cavalier Won't Take Fuel

              Originally posted by solliespont View Post
              How can i know if my car is running with CNG?
              I totally fill up the CNG tank ,but i noticed after using the car 100 miles, that the gas gauge was going down .
              I have no light on on the switch either .
              how to check it out and what can be wrong ?
              Thanks all.
              The cng range on this car will be 120-150 miles. The gauge should go down a lot in 100 miles.If everything is working correctly , the car will default to cng during start-up , unless the tank is down to 400 psi (approx) .If the orange indicator on the fuel gauge rocker switch is not lit , and you think the car IS running on cng , pull the gasoline fuel pump relay and try to start the car. If it starts and runs, great ....you are on cng . The orange indicator light is to tell you the car is on gasoline.

              Others may chime in ...............Stay tuned
              Last edited by Lakewood90712; 10-25-2012, 02:55 PM.

              Comment


              • #8
                Re: Cavalier Won't Take Fuel

                Originally posted by Lakewood90712 View Post
                The cng range on this car will be 120-150 miles. The gauge should go down a lot in 100 miles.If everything is working correctly , the car will default to cng during start-up , unless the tank is down to 400 psi (approx) .If the orange indicator on the fuel gauge rocker switch is not lit , and you think the car IS running on cng , pull the gasoline fuel pump relay and try to start the car. If it starts and runs, great ....you are on cng . The orange indicator light is to tell you the car is on gasoline.

                Others may chime in ...............Stay tuned
                Ok, I did pull the gasoline fuel pump relay and the car didn't start.
                the orange indicator on the fuel gauge rocker switch is not lit and never did since i have the car and i run in gasoline the car do not start on CNG.
                So now I do not hear a "pop" or the CNG Pump turning on when i start the car.
                My CNG tank is totally fill up and my gas tank 3/4 full.
                Thank you for any help.

                Comment


                • #9
                  Re: Cavalier Won't Take Fuel

                  If you press and hold the fuel button, the fuel gauge should show you the CNG tank level. It reverts back to showing gasoline a few seconds after you release the button. You may also want to check the fuse for the CNG system, but I think that would give you a "check engine" light.

                  Comment


                  • #10
                    Re: Cavalier Won't Take Fuel

                    Hmm...maybe the filter is clogged?



                    Depending on the year of the car, I think there's a paper filter (#20 on the image above) that may be involved. Also, the electrical connection to the tank valve could be disconnected. i believe it's an orange wire going to the tank.

                    Comment


                    • #11
                      Re: Cavalier Won't Take Fuel

                      The filter in the drawing is only used on the '03 and '04 Cavaliers. There is a small filter in the top of the HPR but that's it. If the tank is full and the gauge is reading empty, then the high pressure lockoff isn't working or the pressure transducer is bad. Orange light on "fuel" switch would be on when the engine is running. If the gauge reads full, there would be a lot of cranking time before starting, and the low pressure lockoff is most likely bad and on and on down the entire system.

                      Comment


                      • #12
                        Re: Cavalier Won't Take Fuel

                        Originally posted by siai47 View Post
                        The filter in the drawing is only used on the '03 and '04 Cavaliers. There is a small filter in the top of the HPR but that's it. If the tank is full and the gauge is reading empty, then the high pressure lockoff isn't working or the pressure transducer is bad. Orange light on "fuel" switch would be on when the engine is running. If the gauge reads full, there would be a lot of cranking time before starting, and the low pressure lockoff is most likely bad and on and on down the entire system.
                        Thank you for ur help.
                        I cannot even read the guage I tried to hold the switch but it doesn't show me anything else than the gasoline level, the switch is not working as it should.
                        Orange light on "fuel" switch doesn't lit either and never been lit .
                        thanks

                        Comment


                        • #13
                          Re: Cavalier Won't Take Fuel

                          Originally posted by holtek View Post
                          If you press and hold the fuel button, the fuel gauge should show you the CNG tank level. It reverts back to showing gasoline a few seconds after you release the button. You may also want to check the fuse for the CNG system, but I think that would give you a "check engine" light.
                          Thanks for ur help but the switch is dead, it doesn't lit when using gasoline and doesn't show me the CNG tank level.

                          Comment


                          • #14
                            Re: Cavalier Won't Take Fuel

                            If the orange light isn't coming on, there is either no power to the AF-ECU or it is not working. The AF-ECU is the [A]lternative [F]uel [E]ngine [C]ontrol [U]nit located behind the drivers headlamp and operates the CNG system. Check the 20 amp fuse in the underhood fusebox marked CNG and make sure it is in place and not "blown". If the fuse is intact, the orange light should come on for a bulb check and then go out if it is going to try to start on CNG or stay on if it is going to try to start on gasoline. If the light doesn't come on remove the drivers headlight and look for the CNG components located behind it. Check the condition of the wiring conectors at the four relays and the AF-ECU (two big connectors on the bottom) to make sure all are connected and seated properly.

                            Comment


                            • #15
                              Re: Cavalier Won't Take Fuel

                              Originally posted by siai47 View Post
                              If the orange light isn't coming on, there is either no power to the AF-ECU or it is not working. The AF-ECU is the [A]lternative [F]uel [E]ngine [C]ontrol [U]nit located behind the drivers headlamp and operates the CNG system. Check the 20 amp fuse in the underhood fusebox marked CNG and make sure it is in place and not "blown". If the fuse is intact, the orange light should come on for a bulb check and then go out if it is going to try to start on CNG or stay on if it is going to try to start on gasoline. If the light doesn't come on remove the drivers headlight and look for the CNG components located behind it. Check the condition of the wiring conectors at the four relays and the AF-ECU (two big connectors on the bottom) to make sure all are connected and seated properly.
                              TANK YOU i replaced the 20 amp fuse in the underhood fusebox marked CNG and finally got the orange light lit on the roker switch, than i stopped the car turn back on , after waiting 8 sec., and the car started as it should do on cng and the guage show me a full tank.
                              Now after let run the car for few minutes the CHECK ENGINE LIGHT WENT ON?????????????
                              that's my new problem.........any tip to fix it????
                              thanks

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