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2 Cylinders

Discussion in 'XJ Technical Chat' started by granitize, May 5, 2019.

  1. granitize

    granitize Member

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    Hiya..

    Had my '83 XJ550 Seca 550 checked out at the local shop.
    Running like a top!

    Then I put a couple of old OEM flashers on...
    During testing the flash didn't work for a second, and then the engine went down to 2 cylinders.
    Disconnecting the flashers/putting previous ones back on don't help!

    Any thoughts?

    I am an electrical donkey ...but do own a tester.
     
  2. k-moe

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

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    The two events are unrelated, unless there is a fault in the wiring and the wires were moved when you changed the flasher relays out.
    Pull one spark plug at a time, lay the plug on the head, start the engine and check for spark.
    Which two are not firing?
    Cylinder order is (from left to right as you sit on the bike) 1, 2, 3, 4.

    Also check to see that the primary wires (small with spade terminals, under the fuel tank just below the frame backbone) to the coils are still hooked up (do that first).
     
  3. granitize

    granitize Member

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    Hi k-moe.
    Thanks

    The connectors in the attached pic.?
    Thick wire from the harness?
    I see only one spade connector on the right side...
    Doesn't look like I ever had one on the left coil(?).

    No spark on cyl 1 and 4.
    The outside cylinders... both of which connect to the left coil.
    coils.png
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    ohm out the pickup coils, ohm out the ignition coils
     
  5. granitize

    granitize Member

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    Any instructions written with pics for that?
     
  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    the connector on the tci with black gray orange wires is to the pickup coils. left side connector.
    pickup coils
    pickup connector.jpg


    get ohms reading from black wire to gray wire then from same black wire to orange wire.
    Pick-up coils:
    650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range

    ignition coils
    ohm from spark plug wire 1 to spark plug wire 4
    ohm out the primary connector should be red/white wire and orange or gray wire

    XJ550 models:
    Pick-up coils:
    650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range

    Ignition Coils:
    Primary side (input from main wiring harness):
    2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

    Secondary side (spark plug wires, without their end caps):
    11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range
    Spark plug caps:
    10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range

    Spark plugs:
    0 ohms per plug
    Inkedignition coil_LI.jpg
    ohm primary ohm secondary the caps have been removed from secondary so you should get a reading of 11k ohms add 10 if caps are installed
    for primary 2.5 ohms.
     
    Last edited: May 5, 2019
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  7. granitize

    granitize Member

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    Wow... Thanks!
    Will have to do that tomorrow night though.
     
  8. k-moe

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

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    Sorry about my mixup with the primary side connectors. I've been futzing around with a Virago and it has some PO wiring done to it.
     
  9. granitize

    granitize Member

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    k-moe...
    I don't know any better! :)
    So only one primary connector is OK?

    Gonna see if I can figure out the ohm bits from Xj550H.
     
  10. granitize

    granitize Member

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    Umm... Just call me stupid K?
    Some confirmation.

    get ohms reading from black wire to gray wire then from same black wire to orange wire.
    Unplug first and use the female end?

    ignition coils
    ohm from spark plug wire 1 to spark plug wire 4

    ohm the actual wires?
    Pop off the caps and ..red in wire 1, and black in wire 2?

    ohm out the primary connector should be red/white wire and orange or gray wire
    Directly in the primary plug... OK.
     
  11. XJ550H

    XJ550H Well-Known Member Premium Member

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    unplug first you can test connector from back side where wires go into the connector

    yes on the ignition wires from 1 to 4

    you can leave the caps on you will add value of caps to reading
    I like to take caps off and test them individually
     
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  12. granitize

    granitize Member

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    If I did it correctly...

    ohm @ pickup coil connector looks OK.
    Not a digital multimeter...
    but it's a bit above 50 @ x10 so that's marginally over 500 (~ 520?)
    Same plugged/unplugged ...and same on both orange and green -> to black.

    IMG_20190505_1953566.jpg

    ohm from spark plug wire 1 to spark plug wire 4
    Just under 5 ... so maybe too low?
    IMG_20190505_1953566.jpg

    ohm out the primary connector should be red/white wire and orange or gray wire
    Just under 2... so Maybe to low.
    This was the same on both sides.

    IMG_20190505_1956184.jpg
     

    Attached Files:

  13. k-moe

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

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    The ring terminal you circled is the ground, and there only should be one.
    The primary side connectors are circled in XJ55oH's post.
     
  14. XJ550H

    XJ550H Well-Known Member Premium Member

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    meter.jpg

    your meter is set to volts. set black knob to RX1K for plug wires and RX1 for the primarys (to the left of off)
    you also have a red thumb wheel to set it to zero before you start
     
    Last edited: May 5, 2019
  15. granitize

    granitize Member

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    Thanks,
    What makes it be in volts?... I think I'm in ohms... but I don't really know.
    The whole dial turns eh?

    The "off" would move to the little white dot to turn off.
    - 1 click clockwise for RX1K
    - 3 clicks clockwise to RX1

    but yeah... inconsistent in the selections.

    The "set to zero" was off too.

    Will update tomorrow.
     
  16. k-moe

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

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    You need this.
    how-to-use-a-multimeter-and-read-schematics-and-wiring-diagrams.68164
     
  17. granitize

    granitize Member

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    Yes.. and a new digital mmeter as well!
     
  18. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Just be aware the digital MM's don't perform very well on low resistance values. Analog gauges are more difficult to use, but tend to read more accurately at very low resistance values. Of course, you do need to always remember to "zero" the ohms readings every time the meter is used, and every time the "ohms range" (e.g. X1, X10, X100, etc.) is changed.

    If that's an older model Radio Shack meter, it might be a pretty decent one, worth keeping.
     
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  19. k-moe

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

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    You don't need a digital meter. What you have is perfectly fine for the work you'll be doing.
    I still use a $10 analog meter for most things, and I have what used to be a $400 digital Simpson meter at my disposal.
     
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  20. granitize

    granitize Member

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    Yeah - a very old RadioShack model - Put in a new battery so I could adjust to zero!
    That's better.

    Posting the results shortly - Question first.
    Whilst moving things around cylinder 4 came back to life.... ish...

    So I swapped the plugs between 1 and 2.
    2 stayed cold, while 1 had fire.... So plugs maybe too.

    I will get 4 new plugs but the question is:
    Would "failing" coils cause premature plug failure?
     

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