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Discussion Starter · #1 ·
Hi all,

My 4Motion is starting to develop a slight misfire at low revs (1000-2000 rpm). I assume that one of the coil packs is on it's way out, and I want to test each of them. Other than looking for obvious cracks etc., does anyone know what resistance I should expect across the main coil? I could buy a new one and swap each one in turn to see if there's a difference, but I'd like to know for sure if one of them has failed.

Cheers,

Shaun.
 

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Do you have one coil pack or six individual ones? If you have the six induvidual coils, then no need to check resistance. You can test which one is faulty with the engine running. Just simly pull the coils up one by one. The coil which doesnt change how the engine runs will be the one giving you the trouble.

Luke
 

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Do you have one coil pack or six individual ones? If you have the six induvidual coils, then no need to check resistance. You can test which one is faulty with the engine running. Just simly pull the coils up one by one. The coil which doesnt change how the engine runs will be the one giving you the trouble.

Luke
x2!

or if you have one coil pack then you'll just need to change it no matter which output is faulty
 

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Discussion Starter · #4 ·
Hi guys,

Thanks for the response. I do have the individual coil packs, and I was think along similar lines - i.e. unplug each one in turn, and see if it makes a difference. However, ideally I'd prefer something a bit more scientific, such as a coil resistance test. Does anybody have a new coil pack, if so what is the resistance across the coil?

Cheers,

Shaun.
 

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Measure between terminals for cylinder 1 and cylinder 4, and cylinder 2 and cylinder 3. should read 4.0 k to 6.0 k Ohms.

This may not catch a coil that is breaking down under load or from heat. But it the basic go/nogo test.

while your at it check you ignition leads 8k to 14k Ohms.
 

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Do you have one coil pack or six individual ones? If you have the six induvidual coils, then no need to check resistance. You can test which one is faulty with the engine running. Just simly pull the coils up one by one. The coil which doesnt change how the engine runs will be the one giving you the trouble.

Luke
good advice! never thought of doing that before!
 

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Discussion Starter · #7 ·
Thanks rOcK_oN, that's just what I'm looking for! I'll check my coils over the next few days and post back what I find.

Cheers,

Shaun.
 
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