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just purchase 99 f150

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  • just purchase 99 f150

    Hello All

    I just purchase a bifuel f150 with 90k and have a few questions and if anyone could help I would greatly appricate it?

    1) Truck won't run on cng it will start and run realy rough if i hold the pedal just right but will die wery quickly when I let off, any ideas?

    2) I've been looking on the web and found that it says to clean the coalescent filter at every 30k intervals, does any one know where this is located and what it looks like?

    3) Service Engine Soon light comes and goes Autozone checked code and it comes up with an egr valve erorr, truck runs great in gasoline mode would this effect cng mode?

    4) Anyone found or have a price sticker or the incremtal cost ?

    Thanks in Advance


  • #2
    Re: just purchase 99 f150


    I live in Brigham as well and have a few CNG vehicles. I would try to get the vehicle running on gasoline as it shares many systems with the CNG system, then move to troubleshoot any issues with the CNG system (you may find all issues disappear). The codes from the check engine trouble codes are a great place to start troubleshooting.

    Where did you purchase your truck? Do you have any idea of it's maintenance and repair history?


    • #3
      Re: just purchase 99 f150

      It starts and runs great in gasoline mode but bad on cng. I bought the truck on ebay it belonged to Oklahoma City public Works. No documents


      • #4
        Re: just purchase 99 f150

        I think your truck may be a little different from the 2001. But, the coalescent filter is inside the frame under cab on the driver side. It is a black cannister about two inches in diameter and three inches long. There is a small fitting on the bottom that takes a 1/4" allen wrench. This is designed to drain the oil and water, etc. that the filter pulls out. Mine was easy to get to and change, probably as easy as changing the air filter. I would recommend relieving the pressure in the line first. I'm not sure of the proper way to do this, but I imagine if you have the truck running on CNG you could pull the wire to the valve on the tank. I just loosened mine slowly, very slowly and let it vent. It took a few minutes and at first I thought it may be trying to drain the whole tank! However, after a bit, you can hear the pressure just so slightly decreasing. Be careful as it can spit gunk out at you! Also, be sure you are in a ventilated area!
        Before you take the cannister off if you are changing the filter, check very carefully so you can replace it exactly into the same position it was threaded in. The cross frame member on my truck made it so the cannister would bottom out ever so slightly against the frame before it was free. (I imagine this would keep you from loosing the cannister if it ever came loose). I just put some pliers or Vice Grips on the bracket above the cannister and pushed the unit just slightly up and back to clear it.

        Be careful doing this, as I don't really know the correct procedure. However, it is easy to do, and I believe the filters are only about $5 or $6 dollars on the internet. Check the o-ring on the drain valve. Sometimes, the pressure can blow it out when you loosen it.

        Good Luck,



        • #5
          Re: just purchase 99 f150

          Great thread Damon. I too just purchased a 2001 F-150 and have precisely the same question. Appreciate your input too maxman. I've been searching the internet for a GFI Service Manual for mine. No joy yet.


          • #6
            Re: just purchase 99 f150

            I bought a 2003 F150 CNG bi-fuel system diagnostic SHOP MANUAL for the Ford Dealers on ebay. The systems are quite similar to the 2000-2001's. The manual cost me $16.00, but there are isome on there for about $30.00 plus S&H for the 2001.
            One of the things the manual said was it is not unusual for the trucks to run well on gas and not CNG at time. The CNG takes more voltage/power to fire than the gas. It said if the ignition system isn't up to snuff, it may be good enough to run the gas mode well, but not the CNG.


            • #7
              Re: just purchase 99 f150

              Haven't received a manual as yet but... did speak with a knowledgable mechanic about servicing the coalescent filter. I took the connecting wire off the CNG tank, put the bi-fuel switch in ALT fuel position, started the engine and waited until the switch's green light extinguished and it kicked over to gasoline. This process depleted the pressure in the CNG system prior to removing the drain plug on the filter.


              • #8
                Re: just purchase 99 f150

                I’m trying to locate a replacement CNG filter element for my 2001 FORD F-150 Bi Fuel truck. The part number for the filter is A1-412. The replacement element is A1-413.
                Has anybody changed the element? Where did you order it from and what was the part number?

                "Whether you think you can or think you can't - you are right." Henry Ford


                • #9
                  Re: just purchase 99 f150

                  Hey Robert - I'm out of Durango, CO and I too have the same vehicle just purchased a couple of mo ago.
                  I found A-1 Alternatve Fuel Systems in Fresno, CA to be pretty good with parts and quick on the shipping.

                  [email protected]


                  Mary is the receptionist and Mark is probably who you'd want to talk to.

                  Anybody else have a good parts source???



                  • #10
                    Re: just purchase 99 f150

                    In Utah, you can get parts for CNG vehicles from:

                    Salt Lake City

                    Talk to Jared; he shipped me a bunch of parts for my truck. The coalescent filter will cost you about $50 from them.

                    The description by LandL for relieving the pressure in the CNG system is right on.

                    Also, there is a TSB out for the Crown Vic that suggests filling the coalescent filter housing with 90% isopropyl alcohol (you can get 90% at Walgreens) and running the truck for at least 15 min. This might clean the gum out of the low-flow injectors that are responsible for the rough idle.

                    2001 F-150 5.4L Bi-fuel
                    7700 Extended Cab


                    • #11
                      Re: just purchase 99 f150

                      I can sell you the filter for your 1999 bi-fuel Ford F150.
                      Here is a link with information about purchasing the coalescent filter.
                      Last edited by NGXV; 01-30-2010, 06:07 PM.