Won't start one day and fires up first crank next day

Electrical and Ignition

  1. 69DartGTConv

    69DartGTConv Well-Known Member

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    I've been having this issue for about a month. First time it happened I played with the car on a Saturday with no issues, started it many times. Sunday it wouldn't start but it has always cranked over. When I would stop cranking it hinted at starting. It did this over and over. I hot wired it battery to coil directly and still no start. when I disconnected the positive terminal the eng would lurch.

    Yesterday I drove it around the corner and stopped at my friends. While sitting it started die and then it did. All the same symtoms came back and I had to leave iot at my friends and go to work. This morning it started on the first crank and I drove it home??????

    It ign1 run and ign2 crank position?

    new stuff= ignition switch, refurb stock dist no points, mudule and ballast resistor, coil, alt, VR.

    Please correct any ignotance on my part, still learning everyday.
     
  2. 69DartGTConv

    69DartGTConv Well-Known Member

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    I have a color coded 69 wiring diagram.
     
  3. crj1968

    crj1968 FABO Gold Member FABO Gold Member

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    Been learning myself for 40 years......

    Make sure your ECU is grounded well.
    -possibly bad connection at firewall

    Do you have a voltage meter?

    Dual ballast or single?

    Also hot wiring to coil wont make it fire.... fyi you need voltage to ballast and ECU
     
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    • dano

      dano Evil Handy Man

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      Sounds like a failing ignition box if you've converted. I had an orange box do that.

      When you say crank, do you mean the engine turns over but does not fire?
       
      Last edited: Jun 2, 2022
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      • AAndrews

        AAndrews MOPAR .. Move Over, Plymouth Approaching Rapidly!

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        This!!

        First thing to check is to make sure ECU is grounded.
         
      • 67Dart273

        67Dart273 FABO Gold Member FABO Gold Member

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        I've been known to "rig" a temporary pilot lamp or meter connection so I can monitor a "suspect." See if the coil + is getting voltage here is how

        When you go to start it, turn the key to "run" FIRST. Look at coil+. It should be say, 6-8 maybe 10V and NOT as high as battery. This shows it's getting power, drawn "down" through the ballast AND THAT the ECU is grounded AND drawing current.

        Next crank it using the key and look again at coil+ Now it should be "same as battery" and that is, if the battery is pulling down, say, 11.5--11V during crank, then coil+ should be "same."

        Check spark. "Rig" a test gap using SOLID core wire out of the coil tower to a wide gap plug or spark tester gap. I have a Lisle, not terribly expensive, and works.
         
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        • 69DartGTConv

          69DartGTConv Well-Known Member

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          Yes voltmeter, dual ballast. I drove it home from a shop hotwired because ign1 was cut, fixed that first.
           
        • 69DartGTConv

          69DartGTConv Well-Known Member

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          Is Ignition box same as ECU, part of the HEI system? If yes it is new
           
        • crj1968

          crj1968 FABO Gold Member FABO Gold Member

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          yes ECU is the ignition box (not HEI, but similar)

          when you direct wired it to drive it home- how did you do this? Wire from battery to ballast?

          Possibly your dual ballast is in backwards...it can work that way, but makes for hard starting- a car i bought recently had the ballast upside down for lack of a better way to say it. There's a U -shape notch in one side to determine how it goes. 67Dart273's test above will sort that out for you....
           
        • TF360

          TF360 Well-Known Member

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          Mine did this and it was the ECU box
           
        • 67Dart273

          67Dart273 FABO Gold Member FABO Gold Member

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          Yes the ballast orientation. It is just two resistors "the long way" in one "container." The "U" shaped cutout orients it. Proper, unbroken harness connectors are "keyed" so they only go in one way. Otherwise you can look at a wiring diagram and figure it out. The coil+ wiring works just like a 2 terminal points/ electronic ballast. The second section supplied the old "5 pin" boxes. Chances are you don't really HAVE a "5 pin" box, as most have been replaced.

          You can not tell by looking at the ECU as some boxes have 5 physical pins. You have to carefully check resistance from "the 5th" to the other 4 to determine if it's a dummy. More modern "4 pin" boxes can use either a 2 or 4 pin ballast. Older "true" "5 pin" boxes must have a 4 pin ballast
          Diagram below is geared to conversion which is why upper right wire says "existing" THAT is the "run" wire from the key. Notice those two ballast terminals are JUMPERED and that the "U" is at the bottom of the ballast.

          The "bypass" (IGN2) is not shown on this diagram. It connects to the coil+ ballast terminal.
          image-jpg.jpg
           
        • dano

          dano Evil Handy Man

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          Mentioning HEI enter a different ball game. Do you have a factory Ignition box or an HEI conversion? If you not sure attach a picture of what you have.
           
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          • 67Dart273

            67Dart273 FABO Gold Member FABO Gold Member

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            He may be "mis using" the term. HEI was originally GM, period. Since then it has gotten "spread out" into aftermarket and several types of ignition, even though "quite high output" are not "copyrighted" GM terminology. HEI to me means "using a GM module" or a replacement module designed to bolt in replace a GM module

            BY THE WAY many of us has DONE that--replaced the Mopar ECU and eliminated the ballast, with various kinds of GM module

            I usually don't suggest such things during troubleshooting, because you can add problems and complicate the matter
             
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            • dano

              dano Evil Handy Man

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              I've seen people call the big Ford TFI distributors of the late 80's and early 90's with male post caps be called "HEI".
               
            • 69DartGTConv

              69DartGTConv Well-Known Member

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            • 69DartGTConv

              69DartGTConv Well-Known Member

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              Sorry for mixing terms. Had a V8 pinto after HS Class of 79, maybe that is where HEI entered my brain.
               
            • 69DartGTConv

              69DartGTConv Well-Known Member

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              image000000 (13).jpg image000000 (13).jpg
               
            • 69DartGTConv

              69DartGTConv Well-Known Member

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              my current setup. Brn is ign2
               
            • Yote

              Yote Well-Known Member

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              A similar problem for me was a combination of dragging starter and misadjusted timing. You may want to check that out.
              Yote
               
            • oldkimmer

              oldkimmer FABO Gold Member FABO Gold Member

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              I had a 75 fury doing that. Turned out to be the pick up in the distributor. Kim
               
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              • RustyRatRod

                RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                Keep an open mind here. New doesn't mean good.
                 
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                • halifaxhops

                  halifaxhops It's going to get stupid around here! FABO Gold Member

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                  New stuff really sucks 50% chance of sucsess. It is all farmed out even the MP parts.
                   
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                  • RustyRatRod

                    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                    It looks like the crappiest of the crappy for an ignition ECU, too. I hope that wiring isn't indicative of the rest of the car.
                     
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                    • halifaxhops

                      halifaxhops It's going to get stupid around here! FABO Gold Member

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                      That ECU is definately a newer "replaces" one. Definately have seen worse wiring. I would find the plastic plugs for the ballast though they are around.
                       
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                      • 69DartGTConv

                        69DartGTConv Well-Known Member

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                        When I got my car back from a shop, the car wouldn't run. Most of the wiring you see in my pic is from the shop. I removed the ballast and found the ECU only bolted on the bottom flange with a sheet metal bolt. They drilled 6 fn holes in my firewall for the ECU and only one lined up and was used. I know it is not grounded properly, I have work to do.

                        Any pics of what good looking ECU wiring looks like?
                         
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