Low Ohm coil question
 

I swapped my Ducellier coil out with an Accel 8140 I had lying around to see if mine was weak. Sure was. Massive change in performance and even the tone of the engine.

I don't want to us this coil as its a 1.4 Ohm coil. I'm leaning towards putting a Pertronix Flame-Thrower II in it. Good quality coil and if I decide I also want the pertronix ignition it's a match for it. But that coil is .6 Ohms.

Is there any danger in using a coil lower than .8 Ohm like there is using one thats too high?

Not that I have ever experienced.

0.5 is about as low as I have ever had on the V12's.

You might get a general idea of whether a coil pack is defective by comparing the ohmic readings with that of a good coil pack using a digital meter, but that would hardly constitute a foolproof test. What I recommend that you do first is to acquire a code reader for the Jaguar so you can pinpoint which cylinder is the one that's misfiring. Having done that, the best way of determining whether that coil pack is defective is by swapping it with an adjacent coil pack, and see if the trouble code transfers to that adjacent coil pack.

"Good quality coil and if I decide I also want the pertronix ignition it's a match for it. But that coil is .6 Ohms."?
As long as coil matches Pertronix module, all you have to make sure of, that you are using modern resistance spark plug wires. I am using Pertronix module and .6 Ohm coil (XK- 6 cyl) with non-resistance NKG plugs, with a gap of .005" over-book. A real improvement. Rgds. David

Classic XJ Forum
 

The original discussion relates to XJ S1, S2, S3 vehicles. Hard to relate to "Error Codes" & "Coil Pack" issues regardless of similarity. There is a reason we have different Forums for each generation..

Just found I have NO power to the positive side of the coil with the ignition switch in the ON position. ! Thoughts ?

[QUOTE=Excalibur2012;2648109]Just found I have NO power to the positive side of the coil with the ignition switch in the ON position.
But found loose connection, now have power, but still no fire on start. Ordered new Pertronix Flamethrower Coil.