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Well this sucks pretty bad. I'm getting a CATS fault with the new struts. And now I see how I should have tested it. Do nothing more than set the new struts up on the engine area and plug them in. I've done that with my old ones and they work fine. ARGH! What a big mistake this was.
This brings me back to my initial observation. How does a variable 2nd gen. strut work in a 1st gen. CAT system designed only for two settings?
Do you have anyone near you with a 2nd gen car to test the struts on? If you received no error there, it would confirm my concerns that the two are not interchangeable.
This brings me back to my initial observation. How does a variable 2nd gen. strut work in a 1st gen. CAT system designed only for two settings?
Do you have anyone near you with a 2nd gen car to test the struts on? If you received no error there, it would confirm my concerns that the two are not interchangeable.
Vince
I truly expected to get a fault when I put them on my car, but I didn’t, so that’s why I posted earlier that they would work.
I took a gamble on them, based on the Bilstien (sp?) web site listing only one shock (with CATS), across all XK years (IIRC).
I come before you gentlemen truly embarrassed. If this forum wasn't for helping people then I wouldn't even post this. The struts I bought that are for 10s and beyond do work just like KJ said. I realized what I had done as soon as I got one of them off and put the new one that is "supposed" to be for an 07 in the springs. I didn't get the middle nut on the strut tightened down enough for the CAT plug to read it. As soon as I realized it, I took the 2010 stut over to the car and plugged it in. With no nut on it there was no error. So, I took the spring off of the 2007 strut I just got in yesterday and put it back on the 2010 strut. Everything is back on the car and no error. I know I have to get it aligned but the car does feel different. There is no knocking and it sounds solid which is good but it feels different and not in a good way. I'm wondering now if the owner before me had put stiffer struts on it. He upgraded the exhaust system and also put 20s instead of 19s so it stands to reason that there's a good chance he went with a stiffer strut(XKR). I guess I'll reserve judgement until I get it aligned and then go from there.
So, please don't make fun of me too much. I am indeed a novice but hopefully this helps others because there are a lot of 2010-2017 with active damping out there and for much cheaper than the 2007-09.
This brings me back to my initial observation. How does a variable 2nd gen. strut work in a 1st gen. CAT system designed only for two settings?
Do you have anyone near you with a 2nd gen car to test the struts on? If you received no error there, it would confirm my concerns that the two are not interchangeable.
Vince
ClerverName, the only thing I can think of is that the variable 2nd generation is just in the electronics and the strut just does what those electronics tell it. I don't know though, maybe that's why my car is feeling different to me when I drive it.
I come before you gentlemen truly embarrassed. If this forum wasn't for helping people then I wouldn't even post this. The struts I bought that are for 10s and beyond do work just like KJ said. I realized what I had done as soon as I got one of them off and put the new one that is "supposed" to be for an 07 in the springs. I didn't get the middle nut on the strut tightened down enough for the CAT plug to read it. As soon as I realized it, I took the 2010 stut over to the car and plugged it in. With no nut on it there was no error. So, I took the spring off of the 2007 strut I just got in yesterday and put it back on the 2010 strut. Everything is back on the car and no error. I know I have to get it aligned but the car does feel different. There is no knocking and it sounds solid which is good but it feels different and not in a good way. I'm wondering now if the owner before me had put stiffer struts on it. He upgraded the exhaust system and also put 20s instead of 19s so it stands to reason that there's a good chance he went with a stiffer strut(XKR). I guess I'll reserve judgement until I get it aligned and then go from there.
So, please don't make fun of me too much. I am indeed a novice but hopefully this helps others because there are a lot of 2010-2017 with active damping out there and for much cheaper than the 2007-09.
Thanks for clarifying. Yup, getting that nut fully on was 'fun'.
You may not be wrong about "it feels different and not in a good way". As I posted back in #6, the new shocks felt softer than the old shocks, but I attributed it to the fact that one of my old shocks was shot, and probably giving an unnatural ride.
What color were the shocks you took off? The XKR shocks are typically green, while the XK shocks are black.
The ride is much better. I just read that it takes some time for new struts to get adjusted and feel right so I'm hoping that's the case. The good thing is I went from a clunking sound over every small bump to nothing but solid. The bad, I have a new rattle near the passenger side dash I've never heard before. Argh, I HATE rattle sounds and this one is bad.
One other question- my cig ligther, vanity mirror on passenger side both don't work. Are they by chance on the same fuse? I have to go thru the fuses I guess. Now that I think about it the USB plug-in in the glove compartment isn't working either.
Only thing left to do is figure out my drivers side TPMS. When I had NTB put on my new wheels and new tires they moved those over and put on new seals but now the front drivers side doesn't work. They told me the old one is out and I need to buy a new one. Yeah, it just happened to go out while you were changing it over.
ClerverName, the only thing I can think of is that the variable 2nd generation is just in the electronics and the strut just does what those electronics tell it. I don't know though, maybe that's why my car is feeling different to me when I drive it.
No worries. I was interested, so I went back and reviewed both generation ADCM systems.
Although similar in function, they are controlled in very differently ways electrically. What I suspect is that you are not really getting a 'soft' setting. Or if you do, then is is barely above the default (firm) setting.
Educated guess, so hear me out.....
Both generations default to firm with no voltage or current provided.
How does a 1st gen shock work?
When commanded to go soft, the 1st gen ADCM sends a 400Hz signal at 1.3 amps to open the shocks internal valve. Then after 75ms, current is reduced to 0.5 amps (refered to as a ‘holding current’).
The initial high amperage insures the valve solenoid physically moves quickly, but once set, it only requires 0.5A to maintain it.
How does does a 2nd gen shock work?
First remember that it is fully variable. The valving is controlled by varying the current applied to a solenoid controls a tapered orifice. To achieve a soft setting, the ADCM sends its maximum signal of 526Hz signal at 1.5 amps. At that point, unlike the 1st gen, there is no holding current! Instead, a continuous 1.5 amps is required to maintain that particular soft setting. Variable dampening comes from infinitely increasing or decreasing the amperage between 0 amps and 1.5 amps.
Lastly, how will a 2nd gen shock work with a 1st gen ADCM?
When set to soft, the 1st gen ADCM will send a much lower voltage and current to the 2nd gen shock due to its 1st gen design limits. Although lower V and A may be enough to trigger the valving to somewhere near 'soft', the fact that ADCM drops the current immediately to 0.5A (after 75ms by default) tells me the variable shock will then readjust itself to the much firmer setting that only 0.5 amps would represent.
This may even be less considering the lower voltage at 400Hz (4/5th the expected voltage)….
What about a CATS error?
The CATS 'failure' from a shock can only be triggered by current outside the acceptable range, say 2A or more indicating a shorted solenoid, or no current at all, indicating an open solenoid. (‘Current sensing’ is very common in electronic circuits.)
So that's my educated guess looking over both the service manual and the electrical guide. I believe you have forfeited your soft settings installing 2nd gen shocks.
Vince
Last edited by CleverName; 01-26-2019 at 12:10 AM.
Reason: formatting and clairity and now spelling!
No worries. I was interested, so I went back and reviewed both generation ADCM systems.
Although similar in function, they are controlled in very differently ways electrically. What I suspect is that you are not really getting a 'soft' setting. Or if you do, then is is barely above the default (firm) setting.
Educated guess, so hear me out.....
Both generations default to firm with no voltage or current provided.
How does a 1st gen shock work?
When commanded to go soft, the 1st gen ADCM sends a 400Hz signal at 1.3 amps to open the shocks internal valve. Then after 75ms, current is reduced to 0.5 amps (refered to as a ‘holding current’).
The initial high amperage insures the valve solenoid physically moves quickly, but once set, it only requires 0.5A to maintain it.
How does does a 2nd gen shock work?
First remember that it is fully variable. The valving is controlled by varying the current applied to a solenoid controls a tapered orifice. To achieve a soft setting, the ADCM sends its maximum signal of 526Hz signal at 1.5 amps. At that point, unlike the 1st gen, there is no holding current! Instead, a continuous 1.5 amps is required to maintain that particular soft setting. Variable dampening comes from infinitely increasing or decreasing the amperage between 0 amps and 1.5 amps.
Lastly, how will a 2nd gen shock work with a 1st gen ADCM?
When set to soft, the 1st gen ADCM will send a much lower voltage and current to the 2nd gen shock due to its 1st gen design limits. Although lower V and A may be enough to trigger the valving to somewhere near 'soft', the fact that ADCM drops the current immediately to 0.5A (after 75ms by default) tells me the variable shock will then readjust itself to the much firmer setting that only 0.5 amps would represent.
This may even be less considering the lower voltage at 400Hz (4/5th the expected voltage)….
What about a CATS error?
The CATS 'failure' from a shock can only be triggered by current outside the acceptable range, say 2A or more indicating a shorted solenoid, or no current at all, indicating an open solenoid. (‘Current sensing’ is very common in electronic circuits.)
So that's my educated guess looking over both the service manual and the electrical guide. I believe you have forfeited your soft settings installing 2nd gen shocks.
Vince
Hmmm, makes me want to put the others on and try them but I also don't want to lose the ability to get my 680.00 back. I also don't know if I want to spend 3.5 hours taking these off and putting those on. None of it's difficult except for the cranking down and out of the spring. That did a number on my shoulders. I think I'll drive around on the 2nd gens and see how they do. I don't want to not have the softer setting though so I have a lot to think about. I appreciate you looking into it.
Hmmm, makes me want to put the others on and try them but I also don't want to lose the ability to get my 680.00 back. I also don't know if I want to spend 3.5 hours taking these off and putting those on. None of it's difficult except for the cranking down and out of the spring. That did a number on my shoulders. I think I'll drive around on the 2nd gens and see how they do. I don't want to not have the softer setting though so I have a lot to think about. I appreciate you looking into it.
As I said, it's an educated guess. I'm not a Jag tech, but I am a past electronics tech, certified aircraft mechanic, and now a computer specialist/network administrator. I live and love everything technical! So despite not putting actual test equipment to the system for validation, I think I'm close to the mark about the shocks...
I love my XK for its supple ride, and would (at my age) hate to loose it. My XKR is a rough riding SOB in any setting, and although a hoot to drive, it is not the car I would choose to take on a 1000 mile road trip.
Damnitt Clever. I was all set to not do anything this weekend but now I'm seriously thinking about putting the 07-09 struts on that I have. It's a pretty firm ride but honestly I just don't know because my daily driver is a Range Rover and that's not firm at all so I can't tell.
Here's my question to you. Why would the Bilstein part number be the same on both shocks? Is there something that Jag can change within them? I was thinking the 1st and 2nd generation strut was the same, just different information that the Jag was sending them.
Saying that, I probably have 3 hours to kill tomorrow to change them out. If I don't bang them around I should be able to return either of the sets. If I don't pull off the tie end then I don't have to worry about getting it realigned correct? I just go the realignment yesterday and don't want to do that again within 3 days. (My shoulders are already hating me for the potential of doing this)
All I can say is that Bilsteins info is incorrect. The service manual for both the 1st gen and 2nd gen clearly have different internals.
My XK is pleasant enough to drive, and I can still toss her thru the corners nicely when I want to. In fact a buddy commented that he thought I was faster in the XK than the XKR. I had to admit the XK makes you take advantage of everything you have, while the XKR tends to taunt you into playing with brute force. My Jags have not seen a track, so I really don't have times to prove it one way or another.
Last edited by CleverName; 01-26-2019 at 02:27 PM.
Switched them out. Clever, you were correct. The ones for the 07-09 are softer than the 10s. I appreciate your effort in looking at it and determining that.
The only negative is that I have a slight knock. I didn't get something tightened all the way down. There are only a few things it could be because I used a torque wrench with the correct settings. I'm not a big fan of my lbs torque wrench though because it's difficult to put that much pressure on it and see the gauge.
This has been a long few weeks and I've gone off and on with this stuff at least 4 times. My hands, back and shoulders hurt but it was worth it. I enjoy working on my cars and figuring out new things.
Now on to the convertible top issue. My window has pulled away on a portion.
Switched them out. Clever, you were correct. The ones for the 07-09 are softer than the 10s. I appreciate your effort in looking at it and determining that.
Maybe you could elaborate on a statement you made in an earlier posting about the 10's: "it feels different and not in a good way"?
Did the 10's give your a 'rough' ride?
I ask, because I found the 10's to be much softer, almost spongy, bouncy, compared to my original 'bad' shocks. (well, maybe not that bad... )
Maybe you could elaborate on a statement you made in an earlier posting about the 10's: "it feels different and not in a good way"?
Did the 10's give your a 'rough' ride?
I ask, because I found the 10's to be much softer, almost spongy, bouncy, compared to my original 'bad' shocks. (well, maybe not that bad... )
Hey JK, I'm gonna jump in here... well.... I guess cause I can....
I hope robbing can give you a more personal perspective, rather that blindly believing my technobabble and allowing it to have a placebo effect on his personal experience. I've stressed all along that I can not back my information with scientific facts, so my presentation cannot be considered any more that a theory.
That said, I personally am confident in my understanding, considering the limited technical details provided by Jaguar. That means they are accurate only from my perspective.
Now, If I were to assume you are correct in experiencing a softer ride, then a few things may need to be considered should I try to advance my theory.
First is how certain are you that you have 2nd gen shocks (or robbing for that matter)? Receipts can say anything.
Jaguars 2010 service manual states: CAUTION: The dampers look identical to those on the CATS (computer active technology suspension) system of 4.2L vehicles, but have a different part number. Resistance across the solenoid pins of an adaptive dynamics damper should be 2 to 3.5 ohms; if more than 5 ohms, you should suspect that the damper is from a CATS system.
(Note: I take it that the 2nd gen is no longer referred to as 'CATS')
Check the resistance of your shocks to validate which generation you have.
If in fact you do have 2nd gen, then the another possibility may be that you have lost a seal and the nitrogen preload (about 400psi BTW) on a shock. If you only replaced 2 shocks, I could see the combined effect with one bad shock feeling softer?
Other factors in shock design between the two generations which could be considered variables, are the viscosity of the shock oil, the piston size, the actual nitrogen preload pressures and the orifice size while in the default/firm position.
As you can see, unaccounted variables exist that may lead to your personal experience.
I too am interested in robbings future thoughts on the subject an how they shine light on the subject.
Maybe you could elaborate on a statement you made in an earlier posting about the 10's: "it feels different and not in a good way"?
Did the 10's give your a 'rough' ride?
I ask, because I found the 10's to be much softer, almost spongy, bouncy, compared to my original 'bad' shocks. (well, maybe not that bad... )
KJ, I mainly noticed it in my neighborhood. When going under 30 around my Jag seemed to move more with each bump or change in the road. At 40+ I didn't notice a difference. The car was smooth with either shock. Honestly, it's very subtle and the first day I thought there was a difference but after driving it for a couple of days I can say for sure it's a smoother ride. Enough to pay 3 times as much for the struts? I guess that's a personal thing for people but for me it was worth it because my wife drives it and all she cares about is a good ride.
Clever, how would I go about checking the resistance? I see the two little pins down in the whole. I still have the 10s that aren't boxed up to send back yet so it would be interesting to see if there is a difference there.
Clever, how would I go about checking the resistance? I see the two little pins down in the whole. I still have the 10s that aren't boxed up to send back yet so it would be interesting to see if there is a difference there.
A digital multi-meter is all it should take. Most inexpensive units have an ohm setting, and I think even the cheap ones measure down at least to the 1/10th of an ohm for accuracy.
From there, just measure resistance across the two pins on the shock.
01-24-2019, 05:44 PM
My Jags have not seen a track, so I really don't have times to prove it one way or another.
(well, maybe not that bad... 
