Not getting spark. Now what?

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  • rustybronco
    Forum LongTimer
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    • Jul 2005
    • 14961
    • Marysville, Michigan

    #61
    Process of elimination.

    Ignition coils... good.
    Pickup coils... good.
    Voltage tests... good.
    Point to point resistance checks... good.

    Ignitor...fail
    De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

    http://www.thegsresources.com/_forum...35#post1625535

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    • posplayr
      Forum LongTimer
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      • Dec 2007
      • 23673
      • Tucson Az

      #62
      Originally posted by rustybronco
      Process of elimination.

      Ignition coils... good.
      Pickup coils... good.
      Voltage tests... good.
      Point to point resistance checks... good.

      Ignitor...fail
      Sounds more like a process of inclusion.................

      All the stuff above is factored in and unambiguous if he just follow this:

      After verifying that there is +12V on the Coil(+)

      If the coil(-) is not being modulated then the ignitor is either not grounded or BAD.

      If the coil(-) is being modulated and there is no spark then the coil is BAD.

      modulated means going between a high voltage close to 12V down to a law voltage close to 1 volt as the engine is turned over.

      This is a 5 minute test, as long as you can hold alligator clips between your knees.

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      • rustybronco
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        • Jul 2005
        • 14961
        • Marysville, Michigan

        #63
        Originally posted by posplayr

        If the coil(-) is not being modulated then the ignitor is either not grounded or BAD.
        If there is no input from the pickup coils to the igniter it won't be modulated either.
        Originally posted by fyarl666
        Plus, there's no real way to test if the ignitor is good, is there?
        See Pg 148 in the manual I linked (note the colours might be different than what is on your bike.)
        Last edited by rustybronco; 06-23-2014, 02:38 PM.
        De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

        http://www.thegsresources.com/_forum...35#post1625535

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        • fyarl666

          #64
          Okay, now it gets weird...

          Took the cover off the pickup coils to have a look, everything seemed fine. Did a quick ohms check in the pickup coils, all good there. Sprayed it with a bit if contact cleanser just to clear off any schmutz. Started to set up for a 12v test on the ignitor coil, hit the starter button, and she fired up just line a dream come true.

          I shut it off cuz I don't have a gas tank on it at the moment. But just to be sure, I hit the started button and it fired up again, no problem.

          What. The. Hell???

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          • Grimly
            Forum Guru
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            • Sep 2012
            • 5761
            • Ireland

            #65
            Originally posted by fyarl666
            Okay, now it gets weird...

            Took the cover off the pickup coils to have a look, everything seemed fine. Did a quick ohms check in the pickup coils, all good there. Sprayed it with a bit if contact cleanser just to clear off any schmutz. Started to set up for a 12v test on the ignitor coil, hit the starter button, and she fired up just line a dream come true.

            I shut it off cuz I don't have a gas tank on it at the moment. But just to be sure, I hit the started button and it fired up again, no problem.

            What. The. Hell???
            Poking and prodding likely re-made a dud connection or broken wire. It's still there.
            Dave
            '79 GS850GN '80 GS850GT
            Only a dog knows why a motorcyclist sticks his head out of a car window

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            • fyarl666

              #66
              Originally posted by Grimly
              Poking and prodding likely re-made a dud connection or broken wire. It's still there.
              Right. Back to voltage tests.

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              • tkent02
                Forum LongTimer
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                • Jan 2006
                • 35571
                • Near South Park

                #67
                Originally posted by Grimly
                Poking and prodding likely re-made a dud connection or broken wire. It's still there.
                At least he knows all of his components are capable of working. Wiggle and jiggle the wiring in different places while the engine is running to see if it makes it quit or misfire.
                http://img.photobucket.com/albums/v5...tatesMap-1.jpg

                Life is too short to ride an L.

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                • rustybronco
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                  • Marysville, Michigan

                  #68
                  Be sure and check recharging system voltage while you're at it.
                  De-stinking Penelope http://thegsresources.com/_forum/sho...d.php?t=179245

                  http://www.thegsresources.com/_forum...35#post1625535

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                  • fyarl666

                    #69
                    Originally posted by rustybronco
                    Be sure and check recharging system voltage while you're at it.
                    Yeah, gonna do all the stator tests and RR tests that I can think of while it's running before riding anywhere.

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                    • fyarl666

                      #70
                      One thing I noticed, the sparks aren't really big. I'm used to seeing big fat blue/purple sparks out if a good plug. These plugs are new as if April, but the sparks are pretty thin. They're the right color, not yellow/orange, just not as thick as I thought they'd be.

                      Is that normal? If not, how can I boost that up?

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                      • fyarl666

                        #71
                        Discovered the source of my woes, it's the wire leading from the pickup coil. It connects to a plug inside a rubber boot next to the negative side of the battery. I would nudge that boot and wire every time I took the side cover off. I nudge the wire, bike starts fine. Nudge it the other way, bike sputters and dies.

                        Glad I figured it out!

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                        • posplayr
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                          • Dec 2007
                          • 23673
                          • Tucson Az

                          #72
                          Originally posted by rustybronco
                          If there is no input from the pickup coils to the igniter it won't be modulated either.
                          See Pg 148 in the manual I linked (note the colours might be different than what is on your bike.)
                          That is true as well, and probably some others which is why we should always start by checking the (-) side of the coil.
                          I guess I fixated on the ground because some I was helping with a bike had the issue where they were using the ground to prevent engine starting until the stater stopped cranking.

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                          • posplayr
                            Forum LongTimer
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                            • Dec 2007
                            • 23673
                            • Tucson Az

                            #73
                            Originally posted by fyarl666
                            Discovered the source of my woes, it's the wire leading from the pickup coil. It connects to a plug inside a rubber boot next to the negative side of the battery. I would nudge that boot and wire every time I took the side cover off. I nudge the wire, bike starts fine. Nudge it the other way, bike sputters and dies.

                            Glad I figured it out!
                            Most times it is a process of elimination through divide and conquer. Good work.

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                            • fyarl666

                              #74
                              Originally posted by posplayr
                              Most times it is a process of elimination through divide and conquer. Good work.
                              I think this time it was a happy accident I tried to do the 12v test on the igniter coils just after I had Ohms tested the pickup coil. I jiggled the wire back the right way just before trying to start the bike, and that narrowed down the search. After that, it was a pretty obvious culprit.

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                              • posplayr
                                Forum LongTimer
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                                • Dec 2007
                                • 23673
                                • Tucson Az

                                #75
                                Originally posted by fyarl666
                                I think this time it was a happy accident I tried to do the 12v test on the igniter coils just after I had Ohms tested the pickup coil. I jiggled the wire back the right way just before trying to start the bike, and that narrowed down the search. After that, it was a pretty obvious culprit.
                                Sometimes the fastest diagnosis is the lucky or most likely diagnosis. It is really a game of probabilities on top of a process of elimination.

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