The failed strut .......Arnott or Meissler ?

 

Miessler. The supplier has accepted in sending me a new unit under guarantee so not a bad result even thought it’s driven me nuts…

 

So I think I figured out my Damper Firm error = YES. I pulled the trunk trunk trim and found to my surprise the rear struts have the tell tale silver cone on top which means they are aftermarket and that they actually don't have a soft mode. I suppose that makes sense now.

 

Would you please mind posting a short review of the Miessler air-struts one day?
(After purchasing the car I have installed the Arnott air-struts, only later realizing those don't support CATS, womp womp...)

 

I don't believe that will cause an error. They will not be adjustable and will have a constant damper rate but they should not be throwing an error. I have basically done the same thing by installing a resistor (that cone is a heatsink with a resistor underneath) in my two front shocks in order to fault find. What this did was eliminate the firm error which was being caused by a faulty control unit in my front right. The firm error was no more so at least my rears have returned to operating normally improving comfort overall but the fronts have defaulted to firm as they are receiving no inputs form the CATS to soften up.

I would plug in a resistor to the fronts one at a time and see if you have a faulty control unit on a damper like I found.

 

I almost did the same as I discovered later that some of these struts came non dynamic AFTER purchasing the Miesslers... I'll write up my experiences for sure even though I've had a faulty Miessler unit I'm sending back but not getting an exchange as they are out of stock.... So I'm getting a refund and installing a rebuilt set up front. I found a company in Spain who rebuilds these dampers on an exchange basis for under 400€. Will be interesting to campare at least.

 

Looks like I've become an expert on swapping dampers.... So I get my rebuilt unit. Gave me a CATS FAULT on the dash... Got it exchanged, installed the new one. No fault, all good. DAMPER FIRM ERROR = YES!!!! So I'm beginning to wonder if it's not at the damper but more at the control unit side... What I have noticed is that live data gives me DAMPER STATUS = 15 or 0. I get 0 when the car is moving and I don't get a damper firm error. When stopped = 15. But when I get the firmness error, it shows 15 on the move.... Velocity data is ok, so it doesn't seem to be the cause. I'll end up going ARNOTT at the front in the end.... At least the rear will keep the car level and have some body control.

 

Oh no ,did not go through all the replies, but here I am stunned that it might be just another Miessler airstrut not working. We had one of my friends order a whole 4 they ended up being sent back thankfully for their honesty and service . Was to firm constantly . Whatever we did trying to resolve the problem . Put 4 original bilstein on, problems gone.
And I have an guy from italy shewing me out on fb because I just mentioned the name.
so these stories seem to go on and I guess those miessler struts are not just a batch of faulty ones

 

Well that's a scary thought.... Only thing is I have returned back to pre fitment of the front right Miessler which is when it all started and I still have the fault.... Could that shock have damaged something? Maybe I need to do a full on reset and see if it clears up.

 

Seems I have solved the issue albeit it needs some fine tuning.

So I had been running with a 10w 20ohm resistor to disconnect the front shocks and get the rears to operate normally at least... The rears seem to feel more aggressive in firm than the fronts. So having soft rear was a big improvement in comfort but not ideal having default firm up front.

I read somewhere that the early XJ X350's are a bit delicate when installing third party shocks and thought maybe it's all in the resistance not being within tolerances. Now keep in mind I'm ok testing volts but don't know what I'm doing around ohms so help me out here please. I tested the front left (the good side) and got 3.5 ohms. Tested the front right (the bad one replaced twice now) and got 5.6 ohms. Tested the original Miessler that started all this (they haven't asked for it to be returned) and got 4.2 ohms. Decided to run the 20ohm resistor in-line only one of the connector wires to see what would happen and ran it for a few weeks with no problem and with the live data reporting the shock is switching between firm and soft no problem!! I've taken out my non invasive test rig (first pic) and done a proper install with a couple of water proof connectors (second pic) so I can plug and play whatever resistance I need as I think I've gone overboard...

My question is, what can I plug in there to take the resistance from 5.6 to 3.5 for example (or whatever it should be)... or am I good to just walk away and just leave it alone?

 

Well.. actually... you are reading the "DC Ohms" resistance component ....of a finely-wound 'voice coil' AKA 'sensitive' solenoid that ... moves a hydraulic valve between 'binary' (ON/OFF) or (Restrict // NOT Restrict) fluid flow. There are no intermediate positions.


Any 'variation' is accomplished only by how rapidly and how often the valve is switched between wide-open, and part-open.

As a predominantly "inductive" circuit, our prime measurement is in "L" - fractional "Henrys".

"We chickn's" who HAVE NO solenoid valve coil after conversion to EITHER OF coil-over (all mechanical), or Air-strut with no solenoid valve, are applying a resistor in shunt, or directly across the two wires, there being no other electrical components remaining at that 'end'.

Our goal is for it to 'look ENOUGH like' the no-longer present at-all coil's aggregate inductance and resistance TO the pulsed DC driver circuit, that the 'upstream' controller is not aware the coil it is trying to control is outright missing.
- For the coilover mavins, all we seek is that our ERROR messages cease!!!
- For the unmodulated bare but-still-AIR struts adopters, we want the error messages to cease as they ir 'trigger' also shuts-off the air compressor we still NEED.

"With that in mind..." your very DIFFERENT install that either of 'naked' air struts or coilovers, eg: using Miessler air struts that are not Bilstein OEM, but DO still have the / a solenoid control valve and its coil?

- IF.. you have the resistor wired in series with the solenoid coil, then it is functioning as a current-limiter.

- If wired in parallel, it is functioning as a shunt or bypass, 'robbing' a portion of the driver's power meant for the solenoid - and - showing up to the controller as a heavier load.

BOTH choices weaken the power available to the solenoid coil to move the valve. Just in different ways..

'In theory....' so long as Meissler used a compatible solenoid.......NEITHER ONE should be required AT ALL.

So back to 'the real world'......

If there remains a need to fiddle, due to the strut's solenoids not being 100% predictable match to OEM.. or even to each other?

Adjustable resistors.

Lower you dial the Ohms, higher the current draw, so:

A) just don't DO that - it may (or may NOT) damage the upstream controller)

and/or

B) put a fixed resistor - say 3 to 4 Ohms ? - in series with the variable so there is a 'bare minimum' resistance in-circuit, no matter if the variable is dialed-down to zero.

Adjustable resistor should still be a tad stouter than expected load. 25 Watt or 50 Watt?

May as well have 50 Ohms, even if you plan to work down around ten or twenty.
I did say "adjustable"?

And it could be handy for your NEXT detective project, because...

I am more inclined to think that you have damaged wiring (or controller) than I am to expect that Meissler has used more than one value of inductance for the valving control solenoid.

If/as/when that can be sorted, no resistors needed. In YOUR case, anyway.

PS: A "Proster BM4070" Digital LCR Tester will show you figures a Volt-Ohm meter does not.
Cheap. Well-regarded. My one 'matched' known inductances very well. Cheap, too. Very. So I like it.

 

My head just exploded but I got the gist of it. I'm starting to think it has nought to do with the shock too as what currently sits there is a rebuilt unit (brand unknown), not the Miessler, and it behaved in the exact same way as the Miessler... I think removing the rear seat and having a look at the controller might be in order.... wouldn't it be funny if there was just a loose connector that solved all my issues..... dream on!!

 

Now that you mention it there has been at least one or maybe only one
bad connection at the brain behind the rear seat.
It just needed a clean

 

"Funny?" Not the least bit 'new', and "common as dirt' more likely.


Mind, I actually worked with two older guys in the Telco bizness that had worked on 'our end' of the Mukden Cable, War Two and Korean War:

https://www.armysignalocs.com/archiv..._Mukden_2.html

If a fault mechanism exists a "telephone man" hasn't yet seen, hands-on?

We have probably simulated it several ways, already!