preventing catalytic burnout?

Thanks for the info. Yes, it is a 1990! I've had very few problems, then 'bang!' The worst thing of it is that the non-OEM converter doesn't fit as neatly & had to struggle to make room for the oxygen sensor. Bob

1990 XJS, York, PA

Thanks for the tips. I'll check those out. The converter is now hollow! Replaced the parts suggested by the mechanic. I am also wondering about the ignition amplifier. A bit hesitant about starting it up again. Quite a journey and much more complex than my 73 TR6. Bob

1990 XJS, York, PA

Jerry is right. If there is a problem (either with the ignition system or the fuel injection system) that allows unburned fuel to get into the converter, you'll have a repeat experience.

This is doubly true if your XJS is mid-'89 or later with the Marelli ignition. This system, if not 100% maintained, will often fail and leave an entire bank of cylinders dead.

Cheers
DOug Dwyer

Robert, I had the same problem with my '92 XJS. Here is what I learned:

1. Even though the CAT got cherry-red hot, it still was not destroyed. The same one still works fine.

2. The problem was PLUG WIRES. They were toast. That is what allowed raw fuel to be dumped.

3. I also changed the plugs, which were none too good.

4. If the CAT is bad, there are muffler shops who will replace it a lot cheaper than Jag place. In my area, USA muffler is very reasonable.

Sounds like your mechanic has the "replace-anything-that-might-be-remotely-associated" approach. That's o.k. if your Jag is a true "keeper" and you don't mind spending the money, but often is not necessary in my experience.

Good luck,
Jerry K.

1984 XJS coupe
1992 XJS convertible