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how do you test spark plug wires and ignition coils?


douellette

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This is from the FAQ : http://www.w-body.com/forum/index.php?topic=79119.0 and talks about DIS (distributor less ignition system) problems and troubleshooting. This is the part people call "coil packs"

 

As for spark plug wires, you measure them through resistance by placing the multimeter leads on each end of the wire and set it to "Ohms". Resistance of electrical wires varies with length of the wire. If you have a really long wire, its resistance is higher than a really short one, all other things being the same.

 

Most Ws have spark plug wires with similar lengths so what I mentioned above isn't so critical, but some cars now, have coils directly above the plug making the wire really short, so the acceptable resistance will be much lower on those.

 

From what I remember on Ws, most new plug wires will be around 20K Ohms. I believe up to 40K or 50K is acceptable depending on the length. A good rule of thumb is 10K to 15K ohms per foot of wire length.

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alldata calls them good as long as they are less than 30K ohms... for a 3100 anyway.

 

well it is for a 3100 so, haha. and how about the coils, do i just ohm those out too?

 

i went to school for automotives, i just forgot how to test this stuff.

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alldata seems to have different info for different years, even though the parts stay the same...

 

this is for a 94 3100 cutty, but the plug gap makes me think it's meant for a LQ1 since all 3100 pulgs should be .060" IIRC

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alldata seems to have different info for different years, even though the parts stay the same...

 

this is for a 94 3100 cutty, but the plug gap makes me think it's meant for a LQ1 since all 3100 pulgs should be .060" IIRC

 

well this is for a 96 3100 monte.

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there were no changes in this respect for the entire duration of the L82... the wires/coils and almost everything else ignition related was identical.

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there were no changes in this respect for the entire duration of the L82... the wires/coils and almost everything else ignition related was identical.

 

so is the "secondary" of the coil the 2 posts?

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there were no changes in this respect for the entire duration of the L82... the wires/coils and almost everything else ignition related was identical.

 

so is the "secondary" of the coil the 2 posts?

 

yes. the posts are connected to the secondary windings.

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okay so i tested one of the plug wires and it came out to 6.8 K ohms, should i replace them?

 

that passes, even if it was only 1-15 inches...

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