Air shock compressor rebuilt but still air fault and vehicle too low
 

Just got done installing bagpipingandys rebuild kit for my 04 XJR

started car and it sounds like the compressor has much more power but still fails to raise the car and air fault light comes on within a minute or two.

do i need to reset the on board warning light possibly?

anything else I should check for?

aloha

I assume that you have had the Jag jacked up to rebuild the compressor.

Try driving it around the block for up to 20 mins

I've been driving it but still get the fault. I haven't seen it raise at all.
After re starting a few times the compressor seems to be working hard. I can hear it, almost feel like I can feel it vibrating through the gas pedal. It comes on and off then I get the air fault come on. Then the compressor sound goes away.

Seems like the air is getting out somehow....
Any common places to look besides above shock?
I feel like since it never raises that may point to something?
Never worked on an air suspension before

Hi hawaiianjag,


There are a couple of possibilities that come to mind. First, there is a check valve in the compressor between the piston cylinder and the air dryer. If that valve is not sealing properly, all pressure generated by the piston will escape right back into the cylinder and through the leaf valve on the piston when it opens on the intake/down stroke.


Also, there is an electrically-controlled exhaust valve that is part of the compressor assembly. We have had a couple of reports that seem to indicate that the internal components of the exhaust valve can corrode and sieze open, allowing all the air pressurized by the piston to immediately escape.


You may be able to test the exhaust valve possibility by holding your hand or a strip of paper near the exhaust valve outlet port to detect air escaping from the valve. The exhaust valve should never be open while the compressor is running (according to the Manual).


To investigate the check valve, you'd need to pull the compressor again and open up the air dryer. I found corrosion in that part of our compressor, so it might be worth confirming that you don't have a problem with the check valve. I show the check valve location and components in my photos at the links below:


Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page


Other possibilities include leaks anywhere else in the system. If you've checked all the fittings on the tops of the shocks, you could check all the fittings on the valve block and air reservoir.


Please keep us informed. We're trying to assemble enough knowledge to improve our collective diagnostic abilities.


Cheers,


Don

Aloha Don B
 

Thanks very much for the suggestions.

When installing the new piston ring I did notice the check valve was a little raised from the piston, not really bent up but also not super tight against the piston, not sure if that would be normal.

Regarding the exhaust valve, could you point me to the location of where the air could be coming out from if it is I fact the exhaust valve?
I plan to jack up the car and start it to determine if there is air escaping from the compressor while it's running.

Also the other questions I had is the location of the valve block? And is the air reservoir the little tank looking thing that is mounted on the compressor?

Thanks again

Start with the obvious. If the car did raise before it's probably something you tinkered with.

If you have been working on the compressor you have removed and refitted the air line from the compressor. Check if the line is still connected and if it's air tight with soapy water.

Even if the compressor is not 100 points it should lift the car eventually. The only time it wouldn't lift at all on my car is when the air line from the compressor worked itself loose again.

The exhaust valve is on the compressor. The reservoir and valve block is under the spare tire. But start with the things you touched first is my advice.

Guus

Aloha hawaiianjag,

The exhaust valve is the component indicated by the green arrow in photo 6 of Part 1 of my photo albums (the first link of the seven I posted earlier). I think the actual vent is the "half tube" molded into the end of the valve, so you can check for air leaking from that tube while the compressor is running.


That tank or cylinder is the air dryer - my photo albums show how to rebuild this also, beginning in Part 3. The check valve I mentioned is part of the cylinder head, and it's components are shown in Part 4.

Cheers,

Don

Thanks Xag and Don B,

a little background on the issue, Ive had the car for a couple months now, when I bought it the 3rd party dealership had replaced only one of the two front shocks with an Arnott(cheap *******s didn't replace other shock- said it was "okay")
since I've had it I noticed the vehicle too low message would appear if I left the car sitting for more than an hour, but it always would lift up after a minute or two.

Then I had a coolant hose go out, and replaced that along with the thermostat and after the car was sitting for a week while waiting for parts and doing the cooling system job, and it would not raise, this time the vehicle too low light was accompanied by the air system fault.

So it sounds like the problem got worse, I should probably just replace the other front shock with an Arnott anyway, just been putting it off.

Ill report back after inspecting everything again, and hopefully I'm able to get the car to lift without swapping out the other shock

Thanks again

Just my two cents, but I would not spend the money to replace the other shock until you know for certain that you need to. There are far too many other ways to spend hundreds of dollars. If you try all the ideas already suggested and still don't have a clear indication of where the problem lies, I would recommend that you have the system scanned for stored fault codes related to the air suspension. Since you have the warning on the dash, there should be at least one code stored (and possibly several) which will help you with further diagnostics.

Cheers,

Don

Aloha,

right, save your Dollars, no one knows what is coming up next.
If you want to change something, how about 4 inexpensive new viton o-rings
(ID 6mm, OD 8mm) for the air hose connectors on the struts ?

Regards

Reading your messages I think you have some related issues that won't be fixes by replacing the remaining airbag.

If the air line from the compressor is tight then you have to look further. There are several components that could cause a problem and you have to isolate them. You might want to try my setup to determine if your air bags are ok. Replacing those is expensive and you want to check them first.

https://www.jaguarforums.com/forum/showthread.php?t=118966&page=2&styleid=5

If the air bags are okay the remaining parts are air lines, o-rings, valve block and control module.

Guus

Hi hawaiianjag

1st step check compressor output ideally with a guage, no need to open it, simply run the compressor and check the output, a good compressor should hit 200+PSI in 10 -15 seconds running,

if no guage available simply try your finger over the output of the compressor (small threaded hole 4mm pipe) the pressure should be so high it pushes your finger off the end with plenty pressure, it this checks out ok then we can look for either masive leaks or maybe valve issues.

if pressure is bad make sure the piston ring is fitted up the correct way, it will not work upside down, if its ok then we can check one way valves and so on after which ar in the compressor, let us know what you find, any questions please just ask

regards

Andy

regards

Andy

Hi hawaiianjag,

PM me your ebay name, Did you buy the kit form me? hope you didnt by a cheap inferiour one!! :) :)

Regards

Andy

Aloha hawaiianjag,

I think I forgot to mention earlier that the flat piece of metal on top of the piston is the leaf valve, which opens as the piston moves downward to allow fresh air into the cylinder, then flattens to seal the opening so the air can be compressed.

The check valve is on the cylinder outlet port that leads to the air dryer. It prevents the newly-pressurized air from escaping back into the cylinder when the piston retracts. I think my photo albums identify and describe both these valves.

Cheers,

Don

Don:
Thanks again, I definitely wasn't planning on throwing a new shock in to start and hope that fixes everything, just remembering I only have one new arnott shock in the car. I will thoroughly investigate all possible causes of this air escaping before swapping the shock.

Bagpipingandy:
Thanks man! Yep, I bought it from you on ebay (SN: One1l)

Xag- Thanks again, I am going to check the air line tightness and other suggestions you gave right now

LeoJagger:
Thanks man, I will get those rings before ordering the shock, if I don't find the cause of the leak by other means

MANY MAHALOS everyone, Love this forum because everyone is so damn helpful. Makes me confident with buying more Jags throughout the years
this XJR is Jaguar # 4 and I couldn't be happier to own it. Gotta love the supercharger too

Aloha hawaiianjag,

My understanding is that Arnott offers two types of shocks for the X350. One is simply a rebuilt Jaguar/Bilstein unit, and the more expensive option is their own "upgraded" model. Since only one of your shocks was replaced, I would think the odds are good that it is a rebuilt Jaguar/Bilstein shock, and therefore essentially identical in performance to your other, original shock.

Cheers,

Don

Is there a way to get the compressor to kick on because I jacked the car up yesterday and it wasn't coming on, I know if I was driving it would come on after a few minutes usually but for some reason when I jack it up its not coming on so I can't check the pressure coming out of the port that the air line goes to

thanks in advance

You can apply 12V directly to the motor electrical connector. The operation of the compressor is supposed to work something like this:

At startup, if the ASM determines that the air suspension is low on pressure, it will turn the compressor on and run it for up to 120 seconds, at which time it will turn off the compressor to avoid overheating the piston ring and cylinder. If the system is already sufficiently pressurized, the compressor may not start at all.

After the compressor is shut off after 120 seconds, it will not run again until the vehicle exceeds 25 mph, and it will turn off if the vehicle speed drops below 18 mph. The system is designed to mask the compressor noise with road noise and to avoid the compressor running when the vehicle is stopped at traffic lights, for example. During normal driving, the air stored in the reservoir is used to raise the suspension, and the compressor only runs when necessary to recharge the system.

The compressor assembly has two electrical connectors, one for the motor and one for the exhaust valve. For identification of the connectors, see photo 6 in the first photo album I linked to in an earlier post.

Ragman has a current thread in which he shows how he spliced into the motor wiring to power it with jumper cables attached to the battery in another vehicle. If you have or can acquire small alligator clips or spade terminals (I can't recall which half of the connector is male and which is female), you should be able to apply 12V to the compressor electrical connector without cutting into the wiring insulation.

Cheers,

Don

thanks for the detailed explanation Don B
so if I am understanding correctly, if the car has been off for hours and started up again, the compressor should come on right? if it does not that should point to a electrical issue perhaps?
Because I even disconnected the battery and let sit for 10 minutes then tried to start car again yet the compressor was not coming on.
Could the car being jacked up on one side trick the sensor into thinking the level is adequate therefore no compressor kicking on?

By the way I realized that I mounted the compressor on incorrectly after installing new piston ring which is why I initially said the compressor sounds like it has a lot more power, and I could hear/fell it loud when it came on, to the point i could feel it vibrate through the gas pedal. Since I had to take the compressor out, I inspected the new piston ring (seemed to show a lot of wear already(normal?), it is put on correctly, based on the pictures.
I also looked into the cylinder and noticed some rust on that chunk of metal in the bottom of the cylinder next to the piston shaft (sorry don't know term) Could that be something I should worry about?