Dead Cylinders

Electrical & Ignition

  1. Dan The Man

    Dan The Man Well-Known Member

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    69 Charger 440 with electronic ignition conversion. I had a miss and pulled each plug wire at the cap and had no change in idle on cylinders 1,4,6 and 7. Carb was just rebuilt. ??
     
    Last edited: Apr 8, 2021
  2. diesel_lv

    diesel_lv Well-Known Member

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    Check spark plug boots or wires near headers/manifolds. Could be melted. I had same, even w DEI heat covers. Had to go to porcelain boots on all cylinders. Problem solved.
     
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    • Funship32

      Funship32 Well-Known Member

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      How did it run before the carb rebuild? If like crap then was the carb rebuild part of the troubleshooting process? If it ran fine, did you do/touch anything else? If not, did you check for vacuum leaks. If so, what exactly was done?
       
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      • Dan The Man

        Dan The Man Well-Known Member

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        Carb was fine prior, but sat for 5 years with ethanol gas. Ran like crap after, so I rebuilt it. Used the same 1" carb base spacer/insulator when reinstalled. Changed plugs. Nothing else. I did "spray" for vacuum leaks. Nothing found.
         
      • diesel_lv

        diesel_lv Well-Known Member

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        If you don't have one, get a cheap IR heat gun. Check each cylinder exhaust port at manifold/header tube and see if all are Simi. That will also rule out or show a cylinder is not firing.
         
      • diesel_lv

        diesel_lv Well-Known Member

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        Carb will have absolutely nothing to do with a miss on 4 cylinders when he removes plug wire from cap and notices no change.
         
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        • Funship32

          Funship32 Well-Known Member

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          Well I'd say to check the usual suspects. Look at the offending plugs (which you said you changed but see if they are 'wet'), look at the wires, look even more importantly at the cap. Weird as it may sound my Dart (which I wedged a 383 into) would develop an internally arcing cap. Granted it was about 30 years ago but it happened a couple of times where it would work fine and then *poof* run like ka-ka.
           
        • 68Moparmaniac

          68Moparmaniac Well-Known Member

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          I would do a quick continuity test on those "dead" wires, could be wire came out from the terminal at the plug boot.
           
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          • Dan The Man

            Dan The Man Well-Known Member

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            Are these 4 cylinders connected in any way? Through the carb, ignition etc.?
             
          • Ernie ingling

            Ernie ingling Well-Known Member

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            Carb is problem dual plane feeds out board on one side 1&7 also feeds other side 4&6.
            Also loose the spacer
             
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            • Don Frelier

              Don Frelier FBBO Gold Member FBBO Gold Member

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              Check for spark on the non firing cylinders using a good plug on each wire.
              Otherwise Ernie's suggestion maybe a fleck of something clogging one jet passage?
              I'm surprised it runs at all on 4.
               
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              • jamie

                jamie Well-Known Member

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                That's not what he is saying, read it again.

                Compression test first,make sure valves aren't stuck etc. especially sitting for 5 years. Does it tick?
                 
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                • Dan The Man

                  Dan The Man Well-Known Member

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                  No ticking
                   
                • Cranky

                  Cranky Banned Staff Member FBBO Gold Member

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                  Had a similar problem with a TQ carb on a 340 after a rebuild. Lost 2 cylinders on one side and 2 on the other with the stock dual plane intake. Found the problem after dealing with it for several days.....clogged up passage ways in the carb on one side after giving it a light cleaning with a bead blaster. If those 4 cylinders are going to the same side of the plenum, then look at the carb.
                   
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                  • jamie

                    jamie Well-Known Member

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                    Did you drain and clean out the gas tank and lines?
                     
                  • diesel_lv

                    diesel_lv Well-Known Member

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                    @Funship32 my apologies. Wasn't thinking about dual plane and which cylinders each barrel/runner is feeding.
                     
                  • Dan The Man

                    Dan The Man Well-Known Member

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                    That would be the $64,000 question....do those cylinders go to the same side on the 440? Anybody?? That would truly narrow it down.
                     
                  • Nevada dan

                    Nevada dan Well-Known Member

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                    mine was fouling those cylinders , changed the carb , runs great
                     
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                    • Dan The Man

                      Dan The Man Well-Known Member

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                      Yes
                       
                    • Jerry Hall

                      Jerry Hall FBBO Gold Member FBBO Gold Member

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                      What is the carburetor? If it's a carter, it is a typical stuck float on on side or the other.
                       
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