Announcement

Collapse
No announcement yet.

Missfire 6c ...Ford econoline 2004 CNG

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Missfire 6c ...Ford econoline 2004 CNG

    Hello !! My name is Ivan , I’m very new in CNG world. I just got a Ford econoline E350 2004 with my girlfriend CNG. After a week , the engine light went on .. so I got the machine and it wqs a misfire in the cy number 6. I bring to one mechanic , change the sparks (full une up) looks that was fix. A couple days after light went on again .. bring to another mechanic, change the oxygen sensor, clean the injectors .. nothing same problem. I bring to another mechanic and he switch coils 6 to 8 and works fine .. for a week .. the light went on again. Same mechanic change the coil 6 yesterday .. today came again the light, this time with again oxigen sensor problem, missfire on 6 and also random missfire... he said that probably is the wires connection ... anybody has an idea that what can be the issue??
    thanks so much.

  • #2
    Ivan. Probably a good idea to provide more details. What engine? (assuming the 5.4L engine) Is it a dedicated CNG vehicle instead of a bi-fuel? (assuming yes) If the oxygen sensor is being flagged you may have multiple issues and potentially an issue you introduced. How many miles on vehicle? I'd find a mechanic with the Ford IDS scan tool who knows how to use all the features to isolate the problem. If the mechanics did the parts change out correctly, I'd look for any looseness or leakage on the injectors - could be something as simple as a damaged injector o-ring.

    The IDS tool has features such as relative compression, power balance, injector leak down as well as other tests that help isolate the issue much quicker. It is a Ford scan tool so only mechanics that do a lot of Ford repairs are most likely to have it. Otherwise you are throwing parts at the vehicle at this point or hoping to get lucky. One other question - are you noticing anything problematic with the Check Engine Light; roughness, hesitation, loss of power, fuel smell at exhaust, hard starting, reduction in fuel economy or other?

    If you want folks to have a chance of effectively helping you need to provide as much detail as possible. Hard problems require experience, detailed information, determination and sometimes luck.
    Last edited by joe_kan; 3 weeks ago. Reason: grammer issue

    Comment


    • #3
      First thanks so much for answer that quick.
      Yes is 5.4 and transformed to CNG. It used to be an school kids transportation.
      it has 153k.
      When they fixed it after change the coil , it worked perfect , but when the light is on ( sometime fix and sometimes intermittent ) it looks like is losing power , create a vibration and a little of hesitation and rough driving.
      I remember when they did a tuneup up first time , the light went on after two day and was mostly fixe not flashing.
      After this error was missfire 6 and missfire 8. To fix the error the switch number 6 to number 8 and works with not engine light. 4 days later light went again (missfire 6) but not 8. The change new coil on c6.
      works for about 80 miles after. Next day light went on this time mostly flashing 70% of the time.
      now is in the Im the store again with (missfire on 6, oxigen sensor and random missfire).
      they said that probably are the wires..

      If not I will look somebody with this IDS machine.

      You think is a big problem ???

      Comment


      • #4
        Ivan - this does not sound like a CNG specific issue, however, there may be fuel systems problems that may cause this problem. For example, a fuel injector is problematic. When you say the van was "transformed to CNG" does this mean it was an aftermarket solution? What CNG system is on the vehicle - usually a sticker under the hood if an EPA qualified conversion was done? If this is one of these non-EPA aftermarket systems where one taps into the manifold I'd definitely look for leaks This is the kind of detail needed to help you troubleshoot the problem. A mechanic using the Ford IDS scanner has significant advantages over mechanics using other tools since Ford provides proprietary data to the scanner maker (very expensive scanner). The ECM is probably detecting a number of misfires over time and if a threshold is reached that is when the check engine light is illuminated. That is why you do not get the check engine light immediately. The Ford IDS scanner would tell a mechanic the number of misfires on a given cylinder as well as a bunch of other data discussed previously. If I were investigating this without the Ford IDS scanner I'd probably pull out the oscilloscope and look at the signal on the injector for that cylinder at this point to make sure the injector firing is consistent, at the correct level, and no glitches. Id also check the primary and secondary ignition signals on the misfiring cylinder and compare it to the other cylinders. Go to YouTube for details on how to do this. When the plugs were changed, did you gap them properly and were a good quality plug used? All this is speculative until you start isolating the source of the problem. Did the mechanic do a compression test? The Ford IDS scanner can do a relative compression test as well to see if you may have cylinder damage or leaks . Good luck to you.

        Comment


        • #5
          One other thought - since this may not be a CNG specific issue, check the Ford forums for this issue others have had on a 2004 Ford 5.4l engine. This forum is not a repair forum but it is a good place to start especially if you believe the issues are CNG related. The mechanics tried the easy stuff now you need to either find a capable experienced (Ford) mechanic or educate yourself.

          Comment


          • #6
            Just to chime in here. I have a '06 F150 bifuel with a Prins system. A couple years ago I had strange issues with misfire, loss of power during cooler weather. I'd have to pull over, kill the engine and restart on gasoline to get where need be. It turned out to be corrosion on the fuse holders. Replaced fuses and holders. All good ever since. Apparently the engine warming up would condense moisture in the fuse holders in the engine compartment. (fuses that were added with the Prins system)

            Comment


            • #7
              Amfuel - This is great information if you have a Prins system. One of the points I was trying to make to Ivan was that more information is needed. If he does have a Prins system this would definitely be something to check, however, the forum does not know enough to move beyond speculation. If Ivan has a bi-fuel vehicle it would be nice to know whether the behavior is the same on gasoline versus CNG - we don't know. This information could help determine whether it is CNG system related or a more general engine problem. These 5.4l engines could have a misfire for many reasons; sparrk plugs, injector, coil, wiring, crankshaft position sensor, leaks, cylinder damage, timing, ECM, or other. I believe one should methodically isolate the root cause since throwing parts at the vehicle has not resolved the issue. I may have started down the same path. A fresh set of plugs and swapping a couple coils was a good place to start especially since Ivan may not know the vehicle maintenance history. Heck, I might have swapped a couple fuel injectors as well. Been on many forums that discuss vehicle repairs and issues. Two things I've observed. 1.) Folks rarely provide enough detail in their initial post. 2.) Folks tend to not follow-up after the problem is resolved. It is my opinion that if you have asked for help you should try to provide as much detail as possible and when your problem is resolved you should detail the solution that worked for you. Often people neglect that there are others out there that may benefit from the same information. I've seen hundreds of forum threads (outside CNGCHAT) that terminate with "did you ever resolve the problem" or "how did you resolve the problem" with no follow-up.

              Comment


              • #8
                2 years ago on my F150 I had misfires only some times, I had a hard time tracking it down I checked plugs and injectors did not help. I finally tracked it down to the catalytic converter something inside was loose and would block exhaust sometimes and would misfire, I replaced the catalytic converter and no problem in 2 years

                Comment


                • #9
                  gap23 - that is an expensive part to replace without being sure. Any advice for Ivan to troubleshoot? Guess you could bypass (straight pipe) if for a while leaving the upstream O2 sensor in place. Ivan did say he had some oxygen sensor issues so you may be on to something. One would think that 3 different mechanics looking at it would have been able to determine if this was an issue but the quality of the mechanics these days is not so good.

                  Comment


                  • #10
                    Just giving something else to consider, mine started to rattle that is how i found it.

                    Comment


                    • #11
                      I had a misfire like this on my 2002 dedicated CNG crown vic.. Turned out to be a fuel injector. If you move the #6 fuel injector to another cyl and the problem moves you have it. Also a snap on solus scan tools works great for trouble shooting these problems!

                      Comment

                      Working...
                      X