Help - Intermittent no start issues…

General Mopar Tech Discussions

  1. CompSyn

    CompSyn Well-Known Member

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    Issues with 69 road runner. Sometimes it starts no problem and other times it acts like it’s not sparking; No cough. No sputter. Nothing...

    What I got:
    - Breaker Points ignition
    - New OEM Mopar coil
    - New spark plug wires
    - New non-resister Spark Plugs
    - New cap and rotor

    What I see:
    - 7 volts to coil
    - Weak spark at spark plug
    - Fuel does squirt at carb via accelerator pump
    - All my gauges peg negative when cranking the engine over

    Any ideas?
     
  2. Durandal25

    Durandal25 FBBO Gold Member FBBO Gold Member

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    Ballast resistance or voltage regulator sir
     
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    • Durandal25

      Durandal25 FBBO Gold Member FBBO Gold Member

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      If they are new, ground needs a check up
       
    • Durandal25

      Durandal25 FBBO Gold Member FBBO Gold Member

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      Negative to block and block to firewall
       
    • CompSyn

      CompSyn Well-Known Member

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      Good plan. The battery to block ground is the original. AutoZone claims they have one. I'll start there.
       
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      • Billccm

        Billccm FBBO Gold Member FBBO Gold Member

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        Get some nice jumper wires with 18awg wire and alligator clips. Get a 0.5 ohm 5W resistor.
        Next time your no spark happens jumper the coil through the 0.5 ohm to the battery.
        If you get spark and it starts and runs you may have a ballast circuit issue. The ballast resistor could be the cause, but it could also be the spade connectors and crimps. Ignition switch wiring may also be suspect.
         
      • bm02tj

        bm02tj Well-Known Member

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        When cranking engine you should have 9 volts or more at coil as full power from ignition switch bypassing ballast resistor
        If not find where you are losing it
         
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        • CompSyn

          CompSyn Well-Known Member

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          I have a new and old ballast resister I've swapped back and fourth with no difference. Today I tried, momentarily, to jumper straight from the battery to the coil. Still no difference. That takes me back the bad ground idea...

          Also, a buddy of mine who has a 68 Satellite had an identical start issue. He ended up finding that he was loosing voltage at his factory ampmeter. He installed a jumper wire across it and has never had the problem again.
           
        • Don Frelier

          Don Frelier FBBO Gold Member FBBO Gold Member

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          This doesn't sound correct to me?
          The only power showing up on the ammeter should be the amount to pull in the starter relay and the ignition coil.
          Yes there is a big drop due to the starter load but that should come right off the battery.
          To me this is odd. I'll try it on my charger at lunchtime and see how my gauges behave.
          I agree with the engine to body ground wire but the ignition should work fine with just the battery ground to the head.

          What is your choke setup?
           
        • Ranger16

          Ranger16 Well-Known Member

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          I am having the exact same problem. It eventually starts, but not as fast as it should.

          Mine is bypassed and still cranks longer than it should.


          I tried that as well. No help, but the + battery cable got pretty hot.
           
          Last edited: Oct 14, 2021
        • R413

          R413 Well-Known Member

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          Sorry this is long but read it, you might find something of use.

          If your starter cranks fine then the battery cables are fine. They are not causing a no spark if the starter is cranking fine.

          If this is a 1969 and older mopar there is to be a 10 gauge ground from the back of the block to the firewall, it is often missing. The 1970 and newer had a small wire off the negative cable at battery to core support for body ground.

          Your points are a ground switch. The distributor needs to be grounded to the block. The metal housing of the points need to be clean and dry and securely screwed to the breaker plate. The breaker plate needs to be securely screwed to the distributor body. The contacts on the points need to be clean. Check all this stuff. And don’t forget a bad condenser or a tachometer hooked to the coil can do this also. Disconnect the tach.

          Now if none of this helps then go change the coil to a known good one and see if the car starts better.

          The voltage regulator doesn’t do anything before the engine is running, unless it is shorted to ground and melting the wiring when the key is on.
           
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          • Don Frelier

            Don Frelier FBBO Gold Member FBBO Gold Member

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            Good advice.
            My gauges hardly move when I start the charger.
            Maybe check your connections clean them at the starter relay and bulkhead?
            Something seems wrong there.
             
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            • CompSyn

              CompSyn Well-Known Member

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              Update: I replaced the original engine block to battery ground cable. From the negative battery terminal to the aluminum intake manifold I measure 0 ohms, so that should be good, right? I also decided to replace a crimp connector on the distributor wire. Those two things are all I did and the car fired right up and ran. I shut it off and restarted a few times with no issues. When running I measure 9 volts to the coil. All that to say, I'm still a little hesitant to say that those were the problems?

              By the way, I still have the original engine block to firewall ground strap. From that strap bolt on the firewall to the negative terminal on the battery, I measure 0 ohms. Good!?
               
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              • Ironbuilt

                Ironbuilt Well-Known Member

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                Chances are the original ground strap is still good, but you should try cleaning the connections and ensuring that the bolts are tight.
                 
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