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Chrysler 440 weird miss (with video)

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  • Chrysler 440 weird miss (with video)

    My father in law's '69 GTX has an odd miss that we've been chasing but cannot figure out.

    The car has a new Edelbrock carb, new fuel pump, the ignition is a stock appearing dist filled with Pertronix guts, timing is set right, the engine pulls great vacuum. It'll only miss when the motor has a load on it and the "miss" is very evident. It's like the ignition is cutting out for a split second.

    This is shitty video, but whatever. Watch the tach needle in the upper right corner and watch it dip.

    Any ideas on this?

    Last edited by Brian Lohnes; June 10th, 2011, 06:58 PM.
    That which you manifest is before you.

  • #2

    Re: Chrysler 440 weird miss (with video)

    A vacuum advance hooked up? To manifold vacuum?
    Escaped on a technicality.

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    • #3

      Re: Chrysler 440 weird miss (with video)

      Edelbrock carbs have the ported vacuum on the driver's side, I think. Also, check the vacuum advance to make sure the diaphram isn't bad.

      Then, Pertronix units need a minimum of .010 clearance between the magnetic ring and the top of the pickup, maximum of .060. If there is too much slop in the distributor you will get an erratic idle. Just shim the dist. gear to fix it.

      Look down the carb, make sure fuel isn't spilling past the boosters at idle. Sign the floats are off.
      BS'er formally known as Rebeldryver

      Resident Instigator

      sigpic

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      • #4

        Re: Chrysler 440 weird miss (with video)

        Is it just a rough idle, like there's a lot of cam? Mine used to have an idle like that too, I think it was fixed by screwing with the timing a little. Either that or getting rid of the vacuum advance did as well as got rid of the mid-throttle 'stumbling'.

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        • #5

          Re: Chrysler 440 weird miss (with video)

          No, if you watch the tach it idles smooth, then all of a sudden the revs drop, almost like the ignition is cutting out, and then it bouches right back up again. The car will die unless the idle is set high.
          That which you manifest is before you.

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          • #6

            Re: Chrysler 440 weird miss (with video)

            Those Edelbrock carbs are not my favorite item produced by Vic
            sigpic

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            • #7

              Re: Chrysler 440 weird miss (with video)

              Mine was doing the same crap until I shitcanned that freaking e-brock carb.
              If you can leave two black stripes from the exit of one corner to the braking zone of the next, you have enough horsepower. - Mark Donohue

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              • #8

                Re: Chrysler 440 weird miss (with video)

                Those Edelbrock carbs are not my favorite item produced by Vic
                x2
                formerly 1988montecarloss, 3198 posts
                http://bangshift.com/forum/member.ph...88montecarloss

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                • #9

                  Re: Chrysler 440 weird miss (with video)

                  The car will die unless the idle is set high.
                  You got the primary throttle blades open to far and your pulling off the main curcuit. The dead give-a-way is it dying when you try to idle it down. You need to open the secondary throttle blades a little bit or better yet get a Holley........

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                  • #10

                    Re: Chrysler 440 weird miss (with video)

                    I'm with everyone on the Holley sentiment, I like 'em better, too, but I know he wants to keep the edelbrock. Anyway, TC, that's sounds like a good tip. When I go over this morning, we'll work on that tweak.

                    Thanks guys

                    Brian
                    That which you manifest is before you.

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                    • #11

                      Re: Chrysler 440 weird miss (with video)

                      if it's anything like my grandmothers duster. it's under load miss was a weak coil.. it drove us nuts.. untill I brough it to school and hooked it to a scope..

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                      • #12

                        Re: Chrysler 440 weird miss (with video)

                        Hey Brian---

                        Can I ask an obvious question?

                        When did this erratic miss start?

                        I.e., did the miss begin when the Edelbrock carb was installed? Or is it new, started after another change?

                        How long has the E-brock been on? Have the vacuum lines been disconnected/reconnected? Could be just an issue of someone not putting them back in the right places..

                        I'm inclined to think this: If there have been no changes/nobody fiddling with it, then something plum wore out or got gummed up.

                        -bad Vacuum can
                        -cracked vacuum line
                        -dirt in the carb somewhere
                        -dizzy issues like Reb was saying

                        I've had great results with even junkyard E-brock carbs, as long as they're clean, put on right, the filter isn't crap, and they haven't been sitting all winter with gummy gas in them.
                        Yes, I'm a CarJunkie... How many times would YOU rebuild the same engine before getting a crate motor?




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                        • #13

                          Re: Chrysler 440 weird miss (with video)

                          Started before the carb. All vac lines are new. New vac can on dist today. Plug wires are good, checked individual plugs for fire.

                          I think it may be something in the valvetrain, maybe a rocker out of adjustment or something.
                          That which you manifest is before you.

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                          • #14

                            Re: Chrysler 440 weird miss (with video)

                            Started before the carb. All vac lines are new. New vac can on dist today. Plug wires are good, checked individual plugs for fire.

                            I think it may be something in the valvetrain, maybe a rocker out of adjustment or something.
                            Brian,
                            If its got a stock valvetrain, there is no adjustability to the valves. The carb could be out of spec for the engine or have a bad float adjustment? Is there visible gas dripping into the carb at idle? Ive had good and bad luck with edelbrock built AFBs...It could still be the ignition but normally youd have more problems under load. Is the overall driveability good?
                            40 questions...
                            Bruce
                            www.FBthrottlebodies.com
                            Bruce K Bridges

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                            • #15

                              Re: Chrysler 440 weird miss (with video)

                              Hard to tell listening to the vid. I had a similar situation with my Mustang which has the Ecarb. Thought it was the Petronix, ripped that out. Seemed like running the point set up ran better at idle but the funny miss came back. I've richened up the cruise circuit by 1.5% and need to richened up the main a bit as well I also installed a GM style HEI running a #12 gauge wire feeding the dist. Seemes to be running pretty well now. No funny misses.

                              My engine is also very tired. I seemed to be oil fouling #3&4 plugs or something because it was running on 6 cyls at idle even though compression was very even at around 120-130 PSI/cylinder. When I drove the car 150 miles out to my place in PA it seemed to clear things up.

                              Try fattening up the carb. Once they're set they run very well. More then happy with my Ecarb, very smooth and good throttle response
                              Tom
                              Overdrive is overrated


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