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Discussion Starter #1
I'm still trying to diagnose my p0301 misfire and learning while I go. I've come up with a couple of posers that maybe someone knows about.

1st question: If the coils units only have two leads in for the primary coil (battery voltage in and ECU controlled ground to fire), and both HT leads on the unit share the same secondary coil, how does the unit control which HT lead is fired, or does it simply fire both each time and waste a spark in one of the cylinders?​

While testing coil resistance, I took the boot off of the coils and there's a little resistor living between the coil mounted boot and the coil.

2nd question: Is the little resister there to match the resistance of the bottom boot to the resistance of the HT lead with boot attached off the top?

Carrying this thought process further, if the resistance is supposed to be matched between the boot with a resister and the HT leads/boots, it would stand to reason that the HT leads with boots attached should have the same resistance as each other if the coils are interchangeable. I'm afraid to try and take the boot off of the HT leads to see if they have little resisters (at least in the short one) in there as well. The manual only gives HT tolerance in ohm/meter which is really useful when measuring leads significantly shorter than a meter, but if this thought is correct, then the leads with boots attached, should have the same resistance as each other and a difference would indicate that at least one is out. This leads to the third question...

3rd question: Should the two different length HT leads with boots attached have the same resistance as each other?​

or

4th and 5th question: Is there a proper way to measure the resistance in the HT leads? (boot on or off, if they even come off)
and,
Has any body converted KIA's wonderfully stated tolerance of 16k ohm/m to something of relevance for the long and short leads? (Since it is difficult to tell where to measure the distance to and from).​

Thanks,
Warren
 

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Q1 - Both plugs on a coil fire simultaneously - it's called the waste spark system.
Q2 - I'd expect the resistor is there to match resistance.
Q3 - Different lengths will have different resistance.
Q4 & 5 - You should measure the HT leads on their own.

Resistance checks are not final confirmation that a coil and HT leads are in order, as the insulation could be breaking down within the coil or between conductors and ground - to get some idea if the insulation is OK you need to test with a Meggar.

What plugs are you using and what gap?
 

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Discussion Starter #3
Thanks for the reply,

The plugs are NGK BKR6EGP (as were the old ones) gapped at .040 (1.01mm)

As per your response to Q4 and 5, does this mean that I should be able to remove the plug boot from the lead?
 

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Thanks for the reply,

The plugs are NGK BKR6EGP (as were the old ones) gapped at .040 (1.01mm)

As per your response to Q4 and 5, does this mean that I should be able to remove the plug boot from the lead?
I recommend that you gap those plugs to 0.03" (0.75mm) - the larger the gap the more vulnerable the coil and HT lead insulation is to breakdown.
From the Sephia section on the KiaTech web site - the coils and plugs are the same as the Sportage, so the gap should be the same.
Spark plug gap : 0.027~0.031 in (0.7~0.8mm)
Spark plug type : NGK BKR6E
The Sportage section specifies the larger plug gap [0.039-0.043 "(1.0-1.1mm)], but many here have cured their misfire going with the smaller gap.

You should be able to remove the plug boot from the lead.
http://www.kiatechinfo.com/data/PASSENGER/KM/KMA/ENG/SHOP-Images/KM-FB13-IMAGES-ENG/bb3c100a.gif
 
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