My 1987 Jaguar XJ6 had a coil that appears to be leaking oil and breaking down. On the outside is a metal box with two leads. The box attaches to the positive terminal of the coil.

I have a new Bosch coil with an internal Ducellier coil. This coil has places for two wires on the negative side (in addition to the standard negative lead). The positive terminal has three places for wires in addition to the standard positive lead.

I have two white wires that were connected to the external Ducellier coil. Can someone tell me the correct way to wire up this new coil?

Thanks,

Neal Lewis

 

Yikes, that's a little hard to follow.

Ducellier is the manufacturer of the OEM coil fitted to your car, and has an external ballast resistor. The resistor is bolted to the positive side of the coil. Connected to it are the feed wire from the ignition switch, and a feed wire that goes down to the ignition amplifier. Negative side (if memory serves) is white/ black to ignition amplifier, and white/slate/blue for tach.

If the coil you are installing is a resistor coil, you don't use the external ballast resistor. The fact that you may have extra (or different) terminals is a fact of life when you buy aftermarket parts. Just wire it up and don't interchange + side wires with -

 

Hooked up as you say. The coil is a Bosch 0221122023-740. I bought it thinking it was a coil with an internal Ducellier coil. However, it only has the two threaded posts on the outside. So I put the old external Ducellier coil on it. No joy yet.

 

A Series III XJ6 never had a Bosche coil, but one will work fine anyway so long as you connect it as I described. If it is a coil with an internal resistor, don't use the ballast resistor from your original coil. Even if you do, the engine will still probably run anyway. If you bought a coil with no internal resistor, you should re-use the external ballast resistor from your original coil. If you don't, the engine will still run anyway: the coil life will be shortened, that's all. If you have no spark, you have another problem or you are connecting the coil incorrectly.

 

I'm expecting another problem. Just before I replaced the coil, the car got to the place where it would not idle at any speed. I could keep it running barely by changing the accelerator, but even that was not a sure thing. The coil wire was covered with oil as was the coil itself. This particular replacement coil is listed as the correct coil for the 1987 Jaguar XJ6 4.2, but I think, looking at it that it should have come with a Ducellier coil and a resistor.

Thanks for your help and input.