Forgive my ignorance but what is the component I've circled in white? My '89 does not have this item.

 

It’s the ignition amplifier. Inside the box is a GM ignition amp that does the actual work. You’ll need one somewhere if you want to drive the car…

 

Ignition amplifier used on cars with Lucas Ignition.

Your car has Marelli ignition, an entirely different system, which doesn't use the amplifier.

Marelli ignition requires special care. Not sure if you've been briefed on it yet. if not, shout back

Cheers
DD

 

Ah right. Somehow forgot about Marelli cars somehow

 

Thank you very much. Can you refer me to where I might educate myself about the Marelli ignition? Thanks again!

 

Check the attachment for info on "Digitial Ignition", AKA "Marelli Ignition"

In a nutshell the system functions as two systems in one. Two coils, two control modules. And a dual plane ignition rotor within a single distributor. Timing functions controlled by an ignition ECU inside the cabin.

If the plugs are too worn or improperly gapped, or the plug wires develop excessive resistance, the rotor will burn thru...typically in such as way that the engine runs on a single bank of cylinders while the other is nearly dead. The failing bank dumps fuel into the cat converter which over heats and can actually cause a fire. XJSs have burned down this way.

Keeping the system in good order and regular inspection of the rotor can prevent this. Be aware of any loss of power and stop driving if it occurs

Others will chime in with more detail but that's the gist.

Cheers
DD