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cold start issues

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  • cold start issues

    alright i have dedicated cng 2008 impala 3.9l v6 when its 30 degrees or less and it been sitting for 8 hours or more its hard to start once its started no issues running run and drive great

  • #2
    also im confused lil bit cause i know i got 2 tanks in the trunk one small n one big and just discovered that i have a third tank under car where the old gasoline tank was soo how many gallons does this system hold? also i have two stickers underhood one says natural drive and the other is tulsa gas technologys soo who did what?


    • #3
      Some CNG injectors get cranky below frezzing. May be a strange idea depending on where you live....try a block heater. It solved the problem in Alaska


      • #4
        alright pretty good idea also i notice today if it fails to start the first try then i turn the key again but press the throttle a lil and crank itll will start and run it smells like its flooding out


        • #5
          The two small tanks are 2.4 GGE and the large tank is 8.5 GGE for a total of 13.3 GGE. And as we know, due to the heat of compression of natural gas, fast-filling generally provides 80% of the "nominal" capacity so you can generally count on 10 GGE range in the car. Slow-filling with a home refueling appliance such as Fuelmaker will give you a complete fill.

          As with all natural gas vehicles, tanks need to be inspected every 3 years or 36,000 miles, whichever comes first. See the link at the top of any CNGchat page to find inspectors. Tulsa Gas is a good one if you are in the area (they installed the NaturalDrive system).

          I posted the NaturalDrive Owners Guide in another post you started, but for other's enlightenment here is the section on cold starting:

          Cold Weather Starting
          1. Turn off all electrical accessories to reduce the drain on the battery.
          2. Make sure the malfunction indicator lamp goes out before you turn the ignition switch to the START (III) position.
          3. Push the accelerator pedal half way to the floor and hold it there while starting the engine. Do not hold the ignition switch in the START (III) position for more than 15 seconds. When the engine starts, release the accelerator pedal gradually as the engine speeds up and smooths out.
          4. If the engine fails to start in step 3, push the accelerator pedal to the floor and hold it there while you try to start the engine for no more than 15 seconds. If the engine does not start, return to step 3.


          • #6
            thanks for the cold start use to regular gas u dont have to do that lol especially fuel injection lol also whats the reason why i have to do that tho? and by the way thanks was inspected 8/2016 soo good on that lol thats nice to know i have total of 13.3 gge buti know just 10gge used correct?


            • #7
              also where youget the natural drive please


              • #8
                The Dept. of Energy has a nice page and animation to discuss how the heat of compression limits the ability to completely fill a CNG tank. This is why your 13.3 GGE system will generally obtain fills to around 10 GGE from a fast-fill station:

                NaturlDrive was acquired by IMPCO in 2011 and IMPCO was acquired as part of the Westport-FuelSytem merger in 2016. So as a result there is no dedicated NaturalDrive web site. I was part of of the NaturalDrive management team so am happy to help folks here.


                • #9
                  i apprecaite all this info thanks by the way i did the cold start proced and started the second try no issues yay


                  • #10
                    does this cng vehicle have a filter like fuel filter?


                    • #11
                      who does the cleaning and testing of cng injectors


                      • #12
                        There may be a way to find the address for the company mentioned in this other recent thread - Forum | CNG Vehicle Discussion | Honda Civic Natural Gas (GX) | 99 GX not starting after filter and injector changes - but the conclusion at the end of the post says to use new injectors:

                        I took my injectors to RC Engineering to rebuild. Two of them were rebuilt while the other two failed (1 constantly staying open and 2nd intermittent firing and burning out). Cost for the rebuilt was 69.99 (includes shipping) so I was really happy that it was so cheap. Based on this I bought two new ones from Autozone. $169.99 each, with an online code for 20% discount, all in $300. Shipping would take a week (free).

                        I replaced the 2 and 4 injectors with the rebuilt ones. The car started and ran for about 5 mins. I was excited as. I got my car fixed for $68 bucks- winning.

                        Come out the next day which is Sunday and the car will not start. I had been on the forum looking over different causes, but nothing seems like what I experienced.

                        My new parts come in, so back to swapping parts out. Changed out the two old injectors for the new ones.

                        Nothing... Dead in the water... Searching the forums asking questions because this repair has gone sideways......

                        Today I swapped out the rebuild injectors for the old 1 and 3 injectors.... The car stared and ran fine..

                        Moral of the story, although very expensive, buy the new injectors, epic failed for the rebuilt parts. This is on no way dig at RC Engineering as these cng parts seem to be more sensitive and perhaps non serviceable.