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2001 F 150 7700 series concerns

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  • 2001 F 150 7700 series concerns

    We own a 2001 F150 (7700)... We have had it since February, and are very pleased with it. However, last week while driving, it just shut off. Fortunately, we have been able to restart it while driving in neutral. This has happened twice. Should we be concerned? Are there any recalls or inherrant problems with this vehicle?

    Oh, also, where in the world are the spark plugs located?!

  • #2
    Re: 2001 F 150 7700 series concerns

    There are problems, but not a lot like you have described.
    These are famous for popping out the sparkplugs, especially #3.
    The reason you can't see the spark plugs is they are somewhat hidden from view. Each plug has it's on coil on top of the plug and the plugs are under there. That's why you don't see a distributor or spark plug wires like on many other engines. They are difficult to get to, especially the ones on the right side under the CNG components. The fuel rails are also in the way.
    There are many things that could cause truck to quit. Was it running on CNG or Gasoline. Many times when the switch from CNG to gas, there is a hesitation.
    Max

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    • #3
      Re: 2001 F 150 7700 series concerns

      We were running on CNG...
      Yeah, when it switches over it switches pretty hard.

      Thanks for the spark plug info!
      Tracy

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      • #4
        Re: 2001 F 150 7700 series concerns

        Just a thought, it could be in the ignition system, but I sort of doubt it.The Ford Manual on the CNG system says the CNG is harder to fire than Gasoline. An ignition system weakness can run on gas, but misfire on CNG. However, I can't see it shutting the engine down.

        Did it throw a code? (Check Engine Light)

        If not, it is probably a physical problem, as a loose connector, plugged up coalescent filter, or possibly a loose wire. See if you can duplicate problem, both in gas and CNG.

        Did yo have to turn the key all the way off or just move it back to start from run to crank it after you put it in neutral?

        Max

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        • #5
          Re: 2001 F 150 7700 series concerns

          My F-150 started out as a hesitate ~60 MPH when the tachometer was below 2,000rpm and I was giving it throttle to increase speed. It would misfire or miss a cylinder.

          I flushed the CNG fuel system using the sticky for the crown vics. It didn't help the hesitation.

          So I continued to drive the truck on CNG until one day it wouldn't start on CNG. It had plenty of fuel and all it would do was crank.

          I order new coil packs and replaced the plugs and coil packs and still it is intermittent on CNG starting also the hesitation is worse now it hesitates under any acceleration. (I do not recommend anyone who is a weekend auto mechanic to do the coil packs and plugs on this CNG 5.4L bi-fuel. The compuvalve has to be removed, which means the high pressure regulator has to be removed and then getting the coil packs on and off is a nightmare. Also the CNG fuel rails have input fittings in the way that have to be undone. A nightmare that I will take it to a mechanic for next time)

          Now the truck is down with "turbo" at champion ford (See rant below about Thomas Lloyd the CNG service adviser) to get the Compuvalve replaced under warranty. I only have 55,000 miles on my 2001. This ford truck sucks imo. I love my bi-fuel cavalier, but can't recommend the bi-fuel F-150 to anyone. I'll let you know when I get the truck back if the Compuvalve replacement fixed my problem. According to the manual the only two things that can cause the Alt fuel light "ON", No start condition is the MAP sensor and the compuvalve.

          *Rant*
          When I originally felt the hesitation I took the truck down to "Turbo" (Thomas Lloyd CNG service adviser) I told him I was having hesitations on CNG and not gasoline and I wanted him to check the Compuvalve and replace it if it fails check out. The first thing he says is, "We have to do a diagnostic which will cost you $95 and if the compuvalve come up as the problem we will replace it." I said thats fine as long as you check it out and let me know what is causing the hesitation, I'll pay the $95 and fix what is wrong myself if the compuvalve isn't the problem. I left the truck with them and drove home to Ogden area. I get a call 3 days later and he says they found the following: I need to replace the high pressure regulator (leaking slowly), and power flush the CNG system, also they found/repaired a cracked vacuum line going to the compuvalve. I asked, "So the compuvalve isn't my problem?" he said no and that the high pressure regulator is $1,000 and the power flush is $100 and $100 for the fuel filter. I declined all his service I picked the truck up bought the PM-5 or MP-5 (can't remember) and flushed the CNG system. No fix. Then I end up in the no start condition from above. I drove the truck on gasoline and thought I felt the hesitation so I was suspect of the coil packs. I replace the coil pack and plugs, fixed the hesitation I thought I felt on gasoline, however still intermittent no start condition on CNG. I then drive the truck all the way back to Sandy on gasoline due to the CNG not starting. I handed "Turbo" the service my paper work that I paid for a service. I said, "The hesitation has progressed to a no start condition on CNG now. And the ford service manual only has two suspect items Compuvalve and MAP sensor, neither were things you found in the original diagnostic." I told him, "I wanted one thing done REPLACE THE COMPUVALVE like I asked for the first time I was here." He was very rude back to me and threw the service paper work back at me and said, "Ford tells me to do a diagnostic I do a diagnostic." I said that is fine but he needs to check the things I ask him to check the first time. He ended with, "I'll replace the compuvalve, I get paid either way for the work, but if it doesn't fix your problem then that is your problem." I said, "Thank you and I wish you would have listen and done that the first time I brought the truck down." Thomas Lloyd is very rude and won't listen to what you tell him to fix rather he is going to do whatever he wants. Once I get the new compuvalve in I am never going to take my truck back down to him again.
          Last edited by Harpoon; 05-15-2008, 10:10 AM.

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          • #6
            Re: 2001 F 150 7700 series concerns

            Read CNGmotors comment on his experience with "turbo". "Turbo" told him he needed a compuvalve replaced but he didn't have him fix it. It turned out to be a ground problem, which cost just a few dollars to fix.
            On the other hand, my son took his truck to Champion to fix a thrown plug, the rest of the plugs on that bank, and the seals on the injectors. It cost $800 dollars and fixed the miss he'd had before the plug came out. He really liked the guy who worked on his truck and said the guy was really friendly and courteous. Same guy? I don't know.
            Max

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            • #7
              Re: 2001 F 150 7700 series concerns

              Also, I have talked to Ed Kenley Ford in Layton. They have CNG technicians, but I have heard nothing about anybody's experience there.
              Max

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              • #8
                Re: 2001 F 150 7700 series concerns

                Goodfor you,
                I have the exact sma e problem with my 7700 series F-150. Just shut down on the freeway yesterday. Did you find out what was wrong with yours yet?

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                • #9
                  Re: 2001 F 150 7700 series concerns

                  No. It hasn't done it again though.

                  Comment


                  • #10
                    Re: 2001 F 150 7700 series concerns

                    Originally posted by randyr View Post
                    Goodfor you,
                    I have the exact sma e problem with my 7700 series F-150. Just shut down on the freeway yesterday. Did you find out what was wrong with yours yet?
                    Mine shut down on the freeway once. luckily I was in the right lane and could just coast to the shoulder. It had been running rough and I think the check engine light may have been on. After I had it tuned up (i.e. plugs, coil packs, o-rings replaced) it hasn't had a single problem.

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                    • #11
                      Re: 2001 F 150 7700 series concerns

                      Well, it's happening again!

                      Our truck died on us 7 or 8 times in just an hour of driving on CNG. We were on a highway. It seemed to die if you let off of the gas. We switched it over to regular gasoline and it ran perfectly fine. It seems to do this only when it is hot outside. We haven't had a problem since May of last year. Is this a compuvalve or something else? Wouldn't a bad compuvalve show signs all of the time, not selectively?

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                      • #12
                        Re: 2001 F 150 7700 series concerns

                        It did it again this morning. It wasn't that hot, either, so there is no temp connection.

                        *sigh*

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                        • #13
                          Re: 2001 F 150 7700 series concerns

                          Originally Posted by Harpoon
                          Quote:

                          "I declined all his service I picked the truck up bought the PM-5 or MP-5 (can't remember) and flushed the CNG system. No fix."
                          I talked to the mechanics at Go Natural CNG and at Champion Ford about performing the different system flush procedures specified by Ford for the Crown Vics and bi-fuels. They were both strongly opposed to using the Ford PM-5 fuel injector cleaner in the bi-fuel's because it is too strong of a solvent for the compuvalve. The crown Victoria service bulletin only applies to dedicated natural gas Ford vehicles. If you read this bulletin there is specific timing instructions for performing this procedure because the PM-5 is such a strong solvent. There is another Ford bulletin that talks about using 91% or greater isopropyl alcohol in the bi-fuel vehicles. To emphasize this point the Champion Ford mechanic had soaked an o-ring in PM-5 to see what would happen. The PM-5 caused the o-ring to swell rather quickly. After this he began cleaning out the PM-5 by performing an additional flush using isopropyl alcohol. Since then I always include this extra step when performing the PM-5 flush on the dedicated Fords. Seems smart, because if your o-ring or seal is about to go, the PM-5 could finish it off. I have read in other posts where people have used the PM-5 on bi-fuels; however, based on my experience and the advice of these mechanics I strongly recommend only using the PM-5 when flushing the dedicated Crown Victoria's, F-Series trucks and E-Series Vans. Make sure to follow the timing instructions carefully. Use the 91% or higher isopropyl alcohol when flushing the bi-fuel vehicles. When performing system flush, always leave your old coalescent filter installed.
                          Regarding, your truck problems, I would check to make sure your catalytic converter is not plugged. Use a digital infrared thermometer to measure the temperature on each side of the duel exhaust pipes. I was helping an individual I sold a coalescent filter to, to perform a system flush and while I was under the vehicle I noticed how intense the heat was on one side of the exhaust. I check the temperature and it was like 580F on one side and 200F - 300F on the other. This was causing the vehicle to run lean, hesitate, and die. Had this continued it could have burned up his valves.
                          The difficulty with these CNG vehicle drivability issues is that there are multiple issues that cause the same problems. I think Champion Ford should have selection of good compuvalves on hand to use in diagnosing compuvalve failure. If they installed a good compuvalve and the problems go away, then they would know for sure it was the compuvalve. Good Luck!

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