No announcement yet.

Newbie CNG Questions for S-10

  • Filter
  • Time
  • Show
Clear All
new posts

  • Newbie CNG Questions for S-10

    I am new to the forum here and have been interested in CNG for a while now. Unfortunately information seems a bit hard to come by and I have just discovered this forum.

    I found a CNG truck for sale and now that I am ready to get serious about this, I have some questions for anyone that wants to weigh in and help me out.

    I found a 1995 Chevy S-10 single cab truck with what appears to be a factory or very well installed CNG kit. Under the hood is a property tag indicating a government contract so I assume it was at one time a government fleet vehicle. It also has several stickers about CNG not affecting emissions, etc. (backyard mechanics probably wouldn’t bother) So it’s a very professional install. It has 75000 original miles and looks very clean under the hood. The owner bought it at auction and didn’t even know it was CNG, he thought it was propane. He freely admits that he knows nothing about it or whether or not it works in the CNG mode. The power wires which I am assuming are for the CNG part are disconnected. After having looked at the truck, I cant bring myself to buy it without getting answers to the following questions.

    1) Would anyone even consider buying something without knowing if the CNG is functioning? Is it the kind of thing that has very little moving parts and will likely work when the wires are connected and tank filled or could it be a nightmare and possibly I would never find parts?

    2) I assume that the tank is nearly as old as the truck and I am wondering if there are any required inspections on a high pressure tank like a hydrostatic test before I can fill it. I looked for numbers and saw a few but didn’t see a “due date” of sorts… Where should I look?

    3) I live in a “emissions” city where emissions testing is done. Since The CNG shouldn’t affect the gasoline emissions, this should be no problem, Can I find out if CNG is expempt somehow? Are there any special registration requirements?

    4) The guy probably won’t let me drive it to a CNG station and fill the tank to see if it works (that might be the next negotiating step) How can I tell if there is any gas in the tank? There was no special CNG fuel level gage. Should I just hook up the power wires and flip the switch to CNG while it is idling?

    5) I assume this truck gets like 30 gasoline miles to the gallon, will it get 25 GGE miles to the gallon on CNG? Is there a way to roughly estimate what it would be?

    6) I saw a valve at the tank I gave it a bit of a turn, (it was covered in a plastic bag type cover) I also saw a valve under the door between the tank and the engine compartment that was a bit stiff….like maybe a few things need attention or oiling. Is there anything else I should know, look for etc?

    Any advice is appreciated. I know it takes time to write a reply and if I dug long enough I might find the info without bothering anyone. But I never seem to find a cheap CNG truck so I want to move fast if I need to.


  • #2
    Re: Newbie CNG Questions for S-10

    Hard to tell with out trying it.
    Without taking it to an AFV mechanic, theres no way to know if the CNG equipment still even has replacement parts available.
    The valves will be stiff, because they probably have never needed to be turned off.
    I would bet if it is unplugged, there is probably a running issue and that was their answer to keeping it running.
    There have been a lot of CNG suppliers come and go, you may end up with a dead system with no access to replacement parts on this half of the planet.
    A good local AFV mechanic should be in your corner when looking at this truck. If you can post the brand of conversion here, I'm sure there are Chat members that can advise you. But everyone needs a good local mechanic too. As far as the cylinders, if it has a cover over the tanks, you would need to remove it to see the expiration date.
    CNG Cylinders should be inspected every 36 months and after any accident.
    So a truck that old should have several inspection labels on the cylinders too, but probably never been done.
    Dave Clement


    • #3
      Re: Newbie CNG Questions for S-10

      Now that I have a bit more time to browse the Forum I am finding this to be a wealth of good information.

      So if the tank needs to be inspected, and it has probably never been done, what is the method used to enforce the inspection? I'm certainly not trying to get around any rules, just wondering if you can or cant fill a tank that hasn't been inspected, how much it costs etc. (filling and testing would be the quickest way and at least tell me if it works or not) Does the filling station check everytime you fill up?

      I will try to get the info about the system tomorrow. I didn't see anything in the owners manual. Where should I look for the name of the CNG manufacturer?

      Thanks again for the answers.
      Last edited by LASsociety; 05-13-2008, 06:44 PM.


      • #4
        Re: Newbie CNG Questions for S-10

        Send a PM to member CNG MOTORS . Murphy used to sell a lot of them on the used market , so he's got info, if anyone here does.


        • #5
          Re: Newbie CNG Questions for S-10

          Check the door jam and on top of the radiator, fan cowling.
          Should be all kind of warning labels and then a label with manufacturer,
          serial # etc.
          Dave Clement


          • #6
            Re: Newbie CNG Questions for S-10

            Looks like it may already be sold. I knew a deal like this wouldn't last long, that is unless the CNG part wasn't functional and needed parts that are unavailable. Oh well. Better than buying a lemon I suppose. I will keep my eyes peeled and continue to learn what I can and hopefully be able to make an educated decision sometime soon.

            Thanks for the input guys.