Diagnosing Exhaust Sound

General Mopar Tech Discussions

  1. Dan The Man

    Dan The Man Well-Known Member

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    69 Charger 440. Finally got the beast running, but I don't like the "motor boat" sound coming from the exhaust https://app.photobucket.com/u/stump...941f16/p/fdc4576c-e08d-4004-b8e4-7f9c90e01cf1. The entire exhaust is "new" as in never exposed to the elements and always garaged since installed new. The heat riser is just loosey goosey, but I have it tied off counter clockwise to always be open. I just starting using Rec 90 ethanol free gas. Still tuning the carb since I rebuilt it so haven't road tested yet. What do you think?
     
  2. Johnpat

    Johnpat Well-Known Member

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    Sounds like a lot of misfiring to me.
    What happens when you increase RPM??
     
  3. Dan The Man

    Dan The Man Well-Known Member

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    Erractic. I pulled the #1 plug and it is blacked out. I would say oil fouled.
     
  4. dadsbee

    dadsbee FBBO Gold Member FBBO Gold Member

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    Check your plug wire order..
     
  5. Dan The Man

    Dan The Man Well-Known Member

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    Yea its good
     
  6. pnora

    pnora FBBO Gold Member FBBO Gold Member

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    Sounds like its very lean.
     
  7. Dan The Man

    Dan The Man Well-Known Member

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    I'm getting 16 manifold vacuum. Changing plugs. Needed it anyway.
     
  8. R413

    R413 Well-Known Member

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    Sound like the idle circuit in the carb is plugged up.

    Idling to slow. To lean. Richen the mix.
     
  9. Dan The Man

    Dan The Man Well-Known Member

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    OK changed out the plugs. Forgot what a PITA they are. Idle circuit plugged? I just rebuilt the card, so where should I be looking exactly?
     
  10. 1967coronet

    1967coronet FBBO Gold Member FBBO Gold Member

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    What carburetor are you working with ?
     
  11. toolmanmike

    toolmanmike Moderator Staff Member FBBO Gold Member

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    Timing will do that. What's your initial set at?
     
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    • moparedtn

      moparedtn Ed on the Ridge FBBO Gold Member

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      Sounds fine - for a slant six!
      No way that's hitting on all 8 right now.
       
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      • Dan The Man

        Dan The Man Well-Known Member

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        Eddy 1411 750cfm
         
      • Dan The Man

        Dan The Man Well-Known Member

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        Trying to determine that now. What is a good initial?
         
      • toolmanmike

        toolmanmike Moderator Staff Member FBBO Gold Member

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        I start with 10° BTDC and advance from there.
         
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        • 1967coronet

          1967coronet FBBO Gold Member FBBO Gold Member

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          Edelbrock 750 , your 2 air ,idle needles at the front take them out and spray some carb cleaner down each hole.
          Screw them back in easy till the bottom out. Then back out 2 turns.
          That should give you a good start point.
          Like posted set timing 10 degree advance to start with.
          Dbl. Ck plugs for fouling, plug wire condition and fire order like posted.
          Bad distributor cap / rotor possible.
          I've found cracked ( new ) plugs in the box before.
          Just be methodical and test fire thr car after each change you make.
           
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          • Dan The Man

            Dan The Man Well-Known Member

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            OK Cleaned the air/fuel mixture screw holes and adjusted as stated. Ckd timing and it was already at 10. Plugs and wires are new. Cap and rotor fine. I even adjusted the air gap between the reluctor and the pu. It was more than 008. Starts right up. Idles ok but when I gas it from the carb, I get a back fire. Coil?? I've mentioned several times that I now use Rec 90 ethanol free gas for the first time ever. Could this be my friggin problem? It's very frustrating because this car ran awesome before it sat for 5 years. Although garaged and never exposed to the elements.
             
          • khryslerkid

            khryslerkid FBBO Gold Member FBBO Gold Member

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            Double check your firing order. Easy to cross two.
             
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            • Dan The Man

              Dan The Man Well-Known Member

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              I did. Several times. It's even listed on the intake. Counter clockwise.
               
            • Dan The Man

              Dan The Man Well-Known Member

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              Also, I have an electric choke, and the hot side is only getting 8.9 volts??
               
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