Scottie-GNZ Posted January 27, 2002 Share Posted January 27, 2002 I suspect I have a bad coil or coilpack. I was told to do a resistance test and a good coil should have between 11-13 ohms between the posts. I swapped mine out for a good one and all the coils on the good coilpack are indeed between 11-12. My 3 coils were 14.52, 14.88 & 15.05. So, there is a big difference in the resistance and mine is not in the "good" range, but what does it all mean and what about my numbers would make mine "bad"? Please educumate me . BTW, when I ran the car, it just did not feel strong and 2 plugs were very wet and both were on the coil with the lowest number. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted January 27, 2002 Share Posted January 27, 2002 The higher resistance leads to less punch that the coil will develop or pass to the HV side (assuming the measurement was across the LV side of the coil). BUT pure resistance is not the "end" measure of a coil. This particular brand may have more turns on both the HV & LV windings, thus the resistance will be greater, but turns ratio may be the same. Also, the HV winding must be measured too. I don't know what it should be, but it will be higher (much higher I believe) than the LV winding. Compare the HV windings of the new (is it the ground-to-HV measurement?) and old coils and compare them too. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted January 27, 2002 Share Posted January 27, 2002 Also, have you checked (easily seen at night with the engine running in the dark garage) for any HV leakage (blue corona or spark) near the coil HV terminal where much of the energy might be going to ground instead of the plug? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted January 28, 2002 Author Share Posted January 28, 2002 Terry, that is the only test I did as that was the only one I knew to do. The replacment is already installed and I will check for any leakage then go test it Wed night. One of the local Buick turbo shops supposedly has equipment specifically to test this, so I will drop by later this week. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 30, 2002 Share Posted January 30, 2002 ..i dunno...about coil packs...i always thought that all of 'em (in the pack) were just the same as any coil they just had 1 for each cylinder...the primary windings are matched w/the secondary windings so they will be in phase with each other(kinda act as a transformer)..if the enameling breaks down and shorts w/another part of the winding (or melts in two) the the windings arent going to be as perfectly matched and induct the other coil as well...really i think they probably measure capacitance...capacitive reactance to really tell...or maybe that was for impedance...dont really matter..(i just wanted to use some big words)...if their resistance values are different it probably means a wire is leaking,shorted,or burnt open and the primary and secondary windings dont match up as well as they should.....bad sparky...i would think a capacitance test might tell more.... Quote Link to comment Share on other sites More sharing options...
labrat Posted February 16, 2002 Share Posted February 16, 2002 Resistance also affects the recharge time of a capacitor or inductor. Increased resistance in the circuit means more time to recharge, and in a coil this means it takes longer to recharge than you have till the next cylinder fires, resulting in poor spark. Single coil systems have to have big coils to dissipate the heat that very low resistance circuits generate (because of high amperage) Coilpacks can be smaller because they only fire 1/3 of the RPM which means they can recharge slower and use a little more resistance, so less current overall is drawn, and less heat needs to be dissipated. Clear as mud? Quote Link to comment Share on other sites More sharing options...
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