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Ignition coil testing.

Discussion in 'XJ Technical Chat' started by jtalafous, Oct 7, 2008.

  1. jtalafous

    jtalafous Member

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    Hey all,

    I'm aware of the resistance specs that my ignition coil needs to have. My primary checks out fine, but I am having trouble getting anything but infinite ohms on my secondary. Since my bike runs (barely), it must be making a spark, so I must be measuring it wrong. The Clymer manual says to measure between either primary and one spark plug cable. Another source on the web says to measure across both spark plug cables. Which one is correct? Either way gives me infinite ohms.
     
    jtalafous, Oct 7, 2008
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  2. bill

    bill Active Member

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    You measure across the cables. Bear in mind the caps can be 5k or 10k resistor caps. Either remove them or factor that in.

    The caps just screw on - your weak spark could be a bad connection - you can cut a small bit of wire off and reconnect the caps.
     
    bill, Oct 7, 2008
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  3. jtalafous

    jtalafous Member

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    Thanks Bill. I'm might be a little slow, but let me be clear. If I take one lead to my multimeter and put it in the plug cap on one ignition coil (say cyl 1) and put the other lead in the spark plug cap (say cyl 4), and do not get an ohm reading within specs, then that ignition coil is bad?

    (Clymer page 162 figure 24 is wrong then.)
     
    jtalafous, Oct 7, 2008
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  4. kd5uzz

    kd5uzz Member

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    Isn't it cyl #1 and #2 that use the same coil? Shouldn't you use those? and 3 &4?
     
    kd5uzz, Oct 7, 2008
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  5. jtalafous

    jtalafous Member

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    Actually it is 1 and 4 on one ignition coil and 2 and 3 on the other, for an XJ550.

    I got a hold of the official shop manual and YES, Clymer is wrong... measure across the spark plug cables like Bill said.
     
    jtalafous, Oct 7, 2008
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  6. bill

    bill Active Member

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    Yes clymer is wrong and it's 1+4, 2+3 sharing coils.
     
    bill, Oct 7, 2008
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