Many years ago, I bought a 2004 XJ8 used for my wife. This was going to be her commuter car for her education consulting business. It had about 50k miles. Nothing special, base model XJ8. Good shape, black and tan. Over the course of ownership, I have had the usual maladies, suspension, intake leaks, coolant leaks from thermostat housings, radiators, valley hoses. Anyone who has one knows the challenges.
A few years ago, I bought a 2017 Infinity QX50 as a replacement as the reliability was just too sporadic. Nice car btw. So, kept the Jag and gave it to my 20 something son. He took it to Austin, Texas for school and lives there now, still driving it around. Always chasing some issue or another and it now has 150K miles (or so).
At this point it is pretty rough, and the suspension is giving us challenges. We replaced a RR ride height sensor recently and are now having what I think is calibration issues. None of the diagnostic tools that I have will calibrate the suspension and the shops around want $300+ just to look at it.
I liken it to playing golf. You hit that one fine shot at it keeps you coming back to try and change the rotation of the earth with a club. When it works, man what a car. You all know this.
I am trying to determine what to do with it. Sell? Throw another $500 at it in hopes I can limp it along for another 6 months?
So, it begs some questions. Sell it for scrap? Keep fixing it? If I could get the suspension sorted, it might be an option. I just put new tires on it knowing it might be a waste, but safety for my son was the priority. Give me some thoughts.
Anyone in Austin you know would help with the calibration? Thanks in advance for the consideration.

 

Airsuspension new struts or second hand :
Bilstein B4 are the Oe or directely from a owner that swapped his to coilovers
arnott have some as well as coilovers
coilover only and a hit in the x350/358 community are BC Racing coilover adjustable in height and comfort.
Best tool and meant for Those jaguars is Sdd on a Laptop and a Mongoose cable to be able to do a ride height calibration .
front 386mm / 373 on the rear tolerance up or down 15mm.
I CARSOFT LR V3.0 ONLY FROM 2005 ON X356 2005 - 2007 AND X358 2007 TILL 2009 MAYBE WORKING. I TRIED ONE on a 2003 x350 , does not work

 

Arnott airstruts comfort front As2888
Comfort rear As2889
Sport As2890 front

 

Br racing br series for jaguar x350\x358 xj 2003 to 2010 J73TA
coilovers zx 02- br-rs
Fully adjustable height and comfort

 

 

At the compressor you have the compression part where you can exchange the piston ring ( with the green white pen. Bagpipingandy referbkit
at the black pen there are desiccant beads inside that can be exchanged or dried in an owen or microwave. But since the car is in texas now they shoud be dry. If they are humid this alone can cause problems in the (esp )valveblock.

 

Ditch the air for coilovers. Best thing I ever did!

There is NO facility to remove water that gets into the system, and all the valves will rust. The "dryer," which is nothing but a small desiccant chamber in the compressor, is not serviceable without removing and disassembling the compressor. In my case, the desiccant was saturated and the dryer chamber was literally a water tank. Dumped it, installed Arnott coilovers, and never looked back.

 

You will find the beads soaked and the compressor full of water. I live in Texas and that's what I found when taking the air compressor apart to install the new piston ring.
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Thanks for the replies. I tried to respond earlier but my comments were lost in the Cloudflare failure. I did not have time to recreate my thoughts at the time.

Been there done that. I have gone through 5 or more compressors, new shocks, valve block, new suspension components, countless repairs of vacuum leaks, coils (which are now starting to fail again). I just not sure I see putting $2000 worth of suspension into a car that might be worth $5000. This does not include the cooling system maladies.
Since my son has the car in Austin, it has become harder to help him maintain the vehicle. I would like to sort the suspension out but need the calibration. All the shops contacted either will not touch it or want $300+ to even look at it.

Anyway, my problem. Probably just venting at this point but again, I appreciate your thoughts. It will get worked out.

 

The cost of going to coilovers will be less than continued issues with the air suspension. You will not be able to sort the air suspension out for less than that, but even if you could you'd have continued issues in the future. The air system had a design lifetime of maybe ten years, and you're beyond double that with a 2004. Put it on steel springs, the way the automotive gods intended cars to be sprung. Coilovers take nothing away from the car's comfort and they make the suspension 100% reliable.

 

The compressor has a mechanism to get rid of humidity. There is no water or corrosion in my compressor or valve block normally.
About 10 years ago, when I drove 500km under extreme rain conditions, there was a bit of water in the valve block. (Thats also the reason, why I regularly check it.)
I drove a XJ with coilovers once, but it's missing features, CATs provides. (e.g. rough road-mode, highway-mode), so its not the same any more.

I would recommend to buy SDD and do the calibration yourself. It took me 20min to do it.
(As far as I remember, I just entered the car's height on all 4 wheels into SDD and the car leveled correctly.)

 

CATS is nothing but a 2-position valving change to stiffen the damping if you start throwing the car around. It has nothing to do with rough roads or smooth roads, it works on inputs from steering, braking, accelerations, etc., and 90% of drivers would never know it's there. That said, I've never driven a car with working air suspension, with CATS, but the implication above that it switches modes for smooth vs rough roads is not correct.

 

I came across this conundrum several years ago when I needed to replace a couple of the air spring/damper sets. There were not as many options as there are today but overall, I chose to go back with the air spring (Bilstein). I spoke to my son about it, and we would like to try the calibration route but, as mentioned, will need some kind of SDD system.
It makes my head hurt just thinking about one more diagnostic system requiring antiquated computer operating systems and virtual machines. Just shoot me now.
I will entertain your thought on the best path forward with that system and expected costs. Thanks again for the input, I see the paths forward.

 

@wfooshee. You're not right, as these lines from the manual show:

Speed Lowering Mode The speed-lowering mode is a function of drive mode: – When the vehicle maintains a speed of 160 km/h (100 mile/h) or above, and 10 seconds elapse, the suspension lowers 15 mm below the standard ride height. – The suspension returns to the standard ride height when the vehicle speed decreases below 140 km/h (88 mile/h) and 5 seconds elapse.

Rough Road Detection The ASM inhibits the speed lowering function when a rough road surface is detected; the vehicle is raised to the standard ride height to ensure passenger comfort. • Leveling Inhibits The ASM recognizes significant cornering, braking and acceleration actions and inhibits suspension leveling during these periods.

• Inclination Mode The ASM activates the inclination mode when the vehicle is parked on an uneven surface for example, with one wheel on a curb. If the ASM detects what is effectively a sufficient twist between the front and rear axles, the axles will be leveled as a pair. This avoids suspension leveling when the vehicle is moving away

If you attach SDD while driving, you see the CATs controlling height and stiffness. It's the combination of this, what makes the X350 ride in perfection.
Rough road is not an offroad feature, it's used in parking garages, when the first bump is recognized and then the car softens like a baby swing.
Speed lowering is also important, as I often drive beyond 200km/h. The XJ feels like a flying carpet and still remains well connected to the road.

 

@mbwillgrubs I know what you mean, but let me give a tip. During Black Friday/Cyber Monday sales a few years ago, I bought a small Acer windows laptop for $99 and made it a dedicated SDD unit. Stripped off all the junk "free" software and any other software that was not needed to run the Virtual SDD. Disabled wifi so it wouldn't keep trying to update, just made it as barebones as possible expect for SDD. The smaller laptops are also easier to use while sitting in the car, and the one I got had a USB 1 port so it was easy to use with the British Diagnostics SDD.

For under $250 you will have a dedicated SDD, that will also tend to be more reliable for SDD tasks than a laptop used for everyday and connected to the internet. I also have a Range Rover so I get a lot of use out of it.

 

I also went this way. SDD was just too dangerous to have on a computer used for anything else. Plus as Mac Allan pointed out used laptops are a dime a dozen these days. So I also use a cheap dedicated laptop for SDD use only. After wiping and re-installing SDD a few times I learned my lesson!

Another tip? If you get a working SDD setup PLEASE make a backup image of it. Now recovery is much easier!

One additional tip (Especially if you plan to do any data logging to improve your tune) is to get a DC adapter for the laptop. I went with just battery power at first and even added a larger capacity battery for the laptop. But I found you need real power because it will take WAY longer than you planned driving around using SDD. Which is really handy and gets kinda addictive!
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That's all ride height, and none of it has anything to do with CATS. CATS is NOT part of the actual air suspension's ride height control, even though the CATS valving lives in the air struts and is controlled by the ASM. It is a separate system that only controls the stiffness of the damping with a two-position selection, and has nothing to do with ride height. The only thing that makes people think it's part of the suspension is that it's built into the struts and controlled by the ASM, but again, CATS has nothing to do with ride height.

You do NOT see CATS controlling height in the SDD, you see the ASM controlling ride height, and separately, you see the ASM controlling the CATS setting between soft and firm damping. Based on various sensors, the ASM decides to switch to between stiff damping and the normal soft damping, which again, has nothing to do with the ride height. Those sensors are basically telling the ASM that the car is being driven "aggressively" or not. Agressive goes stiff. That's it, CATS does nothing else.

 

Although, I don't remember which module in SDD showed my the values, I checked with dealer training.
(I'm not intending to start a flame war, but I'm still convinced if my view )
To me, ECATs seems to be the combination of air and dampers, which all resides within a single control module.

 

Thanks again for the information.
With respect to the British Diagnostic SDD, which version did you use? I assume V130 as it is offline and does not seem to require a subscription.
What capacity hard drive is required and with what operation system? A virtual machine would be required?

 

I mostly use V125 because I prefer the usability, but V130 also works well as far as I know.

If I remember correctly, Windows XP would be best,otherwise you will probably need a virtual machine.

And do not forget a stabilized power supply for the car if you want to go into deeper diagnostics in the future. The battery will go down fast as the power powers up all electronic modules and will drain about 25A in diagnostic mode.

These threads could help:

https://www.jaguarforums.com/forum/x...estion-265997/

https://www.jaguarforums.com/forum/x...tainer-149395/

Best regards,

Thomas