198,000 mile, 93' 4.0 XJ spark knocking pig

I'm just trying to keep my baby alive!! The spark knocking has been getting slowly worse, so I installed OEM (I have a hookup at the local jeep dealership) cap, rotor, wires, plugs, and decarbonized the cyls. Still spark knocking..... not as bad when 89 octane is used though, but still there (engine slightly warm, hwy in top gear or under slight load). I'm going to put a 180 degree t-stat in tonight hoping that will help some. I've had a flowmaster on it for approx 30k miles, but have stock intake and filter. I've read the mod to relocate the air intake sensor in the air box, but from the article it appears that only really helps richen out the mixture under full throttle, right?? What elso can I do?? I need to either richen the mixture or retard the timing, but don't know of a way to do that. The engine is still running alright (for a 198k mile pig!!) and the AW4 will never die, but I have to beat this spark knock problem before I go to the beach next week..... any ideas??
Thanks, Ben

Does the 93 have the knock sensor on the side of the block ? if so it could be bad and not retarding the spark enough. The other alternative might be to get one of the high altitude CPS's, which is retarded, and swap yours out...
It could also be crummy fuel, hows your state for enforcement of that kind of thing ?
You could also dump in a large bottle of Chevron Techron fuel system cleaner, that stuff does make a difference, I use it in my 98 every 8,000mi or so. I'm at 267,000mi on mine...

After the renix era, I thought they quit using knock sensors and no alternate
cps sensor??

Forget about low temp. t'stats, relocating the IAT sensor, and richening the A/F mixture. The most likely reason your engine's pinging like a mofo is because the combustion chambers and piston crowns are heavily coated with 198k miles worth of carbon. Yeah I know you said you decarbonized them. How? With Seafoam, Mopar CCC? Your engine's probably well and truly coked up especially if you do a lot of short journeys on a cold engine.
Don't believe me? Let me ask you a question. Does your engine tend to "run on" for a second or two after you've switched the ignition off? If so, that's a sure sign your engine's coked up and the only REAL cure is to remove the head and decarbonize it properly. While you're there, have the head surface milled flat, the valve seats reground (3-angle grind), and the valves lapped at a local machine shop. You'll need a full upper gasket set that also includes new valve stem oil seals to complete your head reconditioning job.

Could be but I remember several people mentioned that the CPS sold in colorado and other high altitude states is a different part number from the ones sold in calif, 7 or 9 deg difference if I remember correctly. I kinda remember this from a few years ago both on here and on rec.willys+jeep newsgroups. The cps was sold as a high altitude kit and was also cheaper than the cps by itself. Maybe some fromt he sw chapter can chime in on this. There are some service adivsories on this. A few owners have also said they had 'adjustable' CPS's that would slide on their mounting plate, never seen one myself but it would not suprise me.

The high altitude CPS advances the timing, not retards it. Rock It (Turbo City) sells the adjusable CPS's for around $50, but I'm not sure if they retard timing--they are designed for advancing it.

Run a can of BG44k fuel/combustion system cleaner through the gas. It will clean the injectors and remove a ton of carbon buildup.

When my XJ had spark knock it was from clogged injectors. Granted I only have 100K on mine, but I thought I'd throw that out there.

No knock sensor on these.

My 95 goes through a knocking fit every few zillion miles, and it is usually alleviated by running a course of GM top engine cleaner through it. If you haven't run across this stuff, it involves pouring some down the throttle body, waiting a while, then pouring in enough to stall the engine, waiting a while more, then starting it up and running it till it stops smoking. It makes a huge cloud of nasty looking smoke, so be careful where you do it. It's A LOT of smoke! The only problem I've had with it is that it's nearly impossible to stall a 4.0, so I had to shut it off manually at that stage. You should be able to get the stuff from GM dealers unless they've discontinued it.

It may not be as effective or long-lasting as Dr Dyno's solution, but it is cheaper.

A dose of something like Techron to clean the injectors is a good idea every once in a while too, though it won't do much to decarbonize your pistons and head.