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No spark on cylinders 1 and 2

Discussion in 'XJ Technical Chat' started by Zack Lescowitch, Jul 7, 2019.

  1. Zack Lescowitch

    Zack Lescowitch Member

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    So i just picked up this 1985 xj 700 today with the PO claiming it lost spark after he got caught in the rain last year. He told me he replaced the plugs, plug wires, and coil packs but he still had no spark.

    I brought it home and checked for myself, and sure enough I had no spark on any of the cylinders.

    I followed along with the forum titled:
    How To: Ignition Troubleshooting

    until I got to step 3 in the trouble shooting section. I checked for resistance on the safety cut out wire and at first I had a reading bouncing around from around 400 ohms to 15oo ohms. I retried figuring I wasn't making a good connection with my meter where the wire ran into the plug. And to be sure I was grounding I put the other lead on the negative battery terminal. I heard a few clicks coming from the right side of the bike as I was doing this and had no idea what it was since I was only checking resistance.

    After trying the same procedure yet again, I was unable to produce a reading on my meter nor was I able to make the unknown component click again.

    Again I checked for spark and surprisingly I had spark on cylinders 3 and 4 but nothing on 1 and 2. Being that I was expecting spark on either 1 and 4 or 2 and 3, not 3 and 4, I had no idea what happened.

    Any thoughts on what could've changed that made spark on the right cylinders? Did i damage something when I checked for resistance on the safety cutout?

    Any help is appreciated!
     
  2. Jetfixer

    Jetfixer Well-Known Member

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    A couple of items to check. Check the ground point on both coils , pull all 4 plug caps, un thread swap plug cap 1 and 4 after you unthread trim a 1/4 " off of plug wire , do the same for 2 and 3 see if you have spark .
     
  3. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Make sure that the plug wires are hooked up correctly.
    ( as you sit on the bike) Left coil goes to 1 and 4. right coil goes to 2 and 3.

    It's somewhat likely that a PO messed that up, and that one coil is not connected to the primary, or has failed.
     
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  4. Zack Lescowitch

    Zack Lescowitch Member

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    I made a little progress tonight. I tried checking for spark after going over the plug wires like you suggested and surprisingly I had no spark anywhere.

    I put my meter on the male end of the plug going to the left coil to see if i had power as I was turning it over and I only had 0.5 volts. So I plugged it back together and took the red/white wire off the coil and took a jumper wire from the power input terminal on the coil to the positive terminal on the battery. With this method I was able to manually get spark on cylinders 1 and 4. I did the same with the right coil and got spark on cylinders 2 and 3.

    So I want to say I'm not getting power to the coils via the red/white wires like I should. Since i had spark momentarily before I figured this out, I'm thinking its a loose connection somewhere?

    Also, slightly off topic question: what type of coolant should I put in this bike?
     
  5. Jetfixer

    Jetfixer Well-Known Member

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    Okay I should have asked is your battery fully charged ? A low battery will cause the TCI to not provide spark below 10 volts
     
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  6. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    And it's not just the state of charge of the battery. The voltage under load matters. A battery can charge just fine, but not perform under load.

    Check the voltage at the battery when you're trying to start the engine.
     
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  7. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    It also might be that the sidestand switch is stuck. Peel the boot back, spray contact cleaner into it as you move the plunger. Folllow up with a dry-film siicone lubricant.
    If you still have no spark you can temporarily unplug the sidestand relay. It's located under the left side cover, below the regulator, and has a blue paint mark (or a blue locking tab) at the base.
     
  8. Zack Lescowitch

    Zack Lescowitch Member

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    I had the battery on a trickle charger over night and had 14 volts when I checked after work this evening. During cranking I have between 11 and 12 volts. This should be enough, right? The bike turns over fine; it doesn't sound like the battery is weak.

    If I'm not mistaken, wouldn't the bike still produce spark if the side stand switch were stuck as long as the bike is in neutral?

    I still have no power going to the coils. Does the power come from the tci or the ignition switch at the key? I think I need to trace the red/white wire to figure out where things start to go wrong.
     
  9. XJ550H

    XJ550H Well-Known Member Premium Member

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    yes you should have enough voltage to start bike.

    ignition fuse is feed by key ignition fuse feeds run/kill switch then from switch it goes to tci and to coils

    try disconnecting the black/white wire running from tci it has a bullet connector about 3 inches away from tci.
    if starter button is working your problem is from tci connector to coils. only 1 coil will be hot at a time
     
  10. XJ550H

    XJ550H Well-Known Member Premium Member

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    is this a 700n or X
    do you have that funky relay combo block
     
    Last edited: Jul 8, 2019
  11. Zack Lescowitch

    Zack Lescowitch Member

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    It’s a 700X
     
  12. XJ550H

    XJ550H Well-Known Member Premium Member

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    wiring diagram pull in the clutch see if that works
     

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  13. Zack Lescowitch

    Zack Lescowitch Member

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    I tried it with the clutch in and still nothing. I have about 10.5 volts going into the tci if I put my leads on the red/white and black wires where they go into the plug.
     
  14. XJ550H

    XJ550H Well-Known Member Premium Member

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    is that with starter button pressed and turning over. measure from battery ground and to red white wire

    do a voltage drop test hook meter to battery press starter button what does the voltage drop to?

    could be you have to clean connectors run switch ignition switch(key)
     
  15. Zack Lescowitch

    Zack Lescowitch Member

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    From battery ground to red white wire where it enters the plug for the tci I have between 10.5 and 11.5 volts when it’s turning over.

    Voltage drop test: 11.15 was the lowest reading I saw while turning it over.
     
  16. XJ550H

    XJ550H Well-Known Member Premium Member

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    have you disconnected the black/white wire at bullet connector coming from tci?

    all voltages need to be measured from battery ground.
     
  17. Zack Lescowitch

    Zack Lescowitch Member

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    That’s another issue, there’s no bullet connector on mine.
    There’s bullet connectors for a blue wire and a black/red wire but they don’t go to either of the plugs.
     
  18. Zack Lescowitch

    Zack Lescowitch Member

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  19. Zack Lescowitch

    Zack Lescowitch Member

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    Now if I got from battery ground to the red white wire where it plugs into the plugs right before the coil, I get 0.6v with the ignition on but not turning over. This is true for both coils and when I do the same set up on the corresponding orange and gray wires.

    If I do the same thing when turning it over, it drops to about 0.25 volts
     
  20. XJ550H

    XJ550H Well-Known Member Premium Member

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    x box.PNG I see a black white wire in your photo where does that go?
     

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