Xantia Softer Spheres

Stempy · Post by **Stempy** » 01 Apr 2008, 22:40

I can't say that this for all mk2's but my V6 has the brake pressure switch fitted, it's just not connected to anything, if your facing the engine bay it's down on the right under the airbox area IIRC.

The VN05N part in the ECU is a solid state relay device, probably some kind of MOS FET transistor with built in protection, doubt that Maplins would do them but you might find an automotive electronics specialist that would supply, but couldn't even guess at what price.

DickieG · Post by **DickieG** » 01 Apr 2008, 22:42

One other thing I've discovered is that S2 ECU's appear to have a different protocol to S1's, presumably due to the change from a 30 pin to a 16 pin diagnostic socket. With regard to that I'm hoping to get hold of a Lexia this weekend which (unlike my ELIT) may be able to read the duff ECU provided its not too 'fried up'.

The green fluid appears to have run down from the area of the solid state relays.

Excellent links thanks, it appears to be quite a hot topic on both forums

steelcityuk · Post by **steelcityuk** » 02 Apr 2008, 01:39

One of the first things I do to a Hydractive Citrroen is add diodes to the ECU and fit a hard/soft status LED that can be seen easily whilst driving. These mods cost pennies to do and it's easy to see if the basic electronics are doing what they are suppose to be doing. All my Citroens have been swapping modes exactly as they should whether they have other faults or not. I find I can clear the ECU codes of both the engine and suspension ECUs using just a simple blink code reader, the simple codes can be read too.

As for the amount of suspesion travel, the XM has a big overhang at the front , it is made more for comfort than Xantias are and Georges XM has a 3L V6 it isn't a small lump. I'd hate to think of the price of a pair of struts for a XM, I know that the top mounts are more than twice the price of a Xantias.

I'm still of the opinion that even during Citrerobics the amount of fluid replacement is small. I look at it this way, if there is little to no leak back then there is only 1 pipe into the struts which on a Hydractive Citroen is of a much larger capacity than a non Hydractive Citroen so when you drop the car to it's lowest setting the fluid from the struts goes back along the feeding pipe work to the Hydractive block and maybe as far back as the height corrector. Now you raise the car back to full height and the same fluid you just pushed out of the struts gets pushed back into the struts. This can hardly be a massive turnover of fluid which if trying to flush the system will take a hell of a long time. In fact when changing the Antisink sphere on my XM the fluid that came out appeared to be pure LHM despite the fact that I'd been running Hydroflush for about 1000 miles. Another point is that even after runing Hydroflush for a 1000 miles or so a height corrector was still full of gunk when dismantled. With this in mind I've started bleeding the system using the strut feeds. Within reason I'll try anything that may bring results.

Steve.

Mandrake · Post by **Mandrake** » 02 Apr 2008, 06:55

aerodynamica wrote:I just watched George's video. I can see that he's done everything in the universe to get the XM suspension to ride softer however, looking at that I wonder if he has gone a little over the mark. It seems too soft - it's even softer than my CX (and that is running softer than standard) The XM is hitting its lower stops with the weight of one person - isn't that a little too soft?

Not really - when the suspension on my Xantia was at its best (and with the correct spheres) I could push the rear suspension right down to the bump stops with one hand let alone sitting on it.

Even now that the rear spheres a bit low on gas I can bottom it by sitting in the boot. (And I'm only 80Kg) Hydractive 2 is really that soft - and it relies on switching to the much stiffer "hard mode" to prevent the rear suspension from bottoming during acceleration from a standing start.

If you disconnect the throttle sensor for the Hydractive computer it really is disconcerting how much squat there is at the rear with acceleration from a standing start.

On the other hand the front suspension of his XM looks a wee bit softer than it probably should be, but not by a huge amount.

I must say that the auto self levelling on that XM is up to scratch, so that certainly is a good sign. This is the same as my CX and Xantia, the car relevels after sitting in and after stepping out. The self levelling also affects the ride perception too.

Thats one thing that has always worked well in my Xantia - even relatively small weight changes, for example me getting into the drivers seat will reliably trigger a height correction at both the front and the rear.

Not so on my Dad's Xantia, which wont usually adjust the front suspension for the weight of one person.

Regards,
Simon

Mandrake · Post by **Mandrake** » 02 Apr 2008, 07:00

alan s wrote:Apart from the reasons above, the other thing that needs to be taken into account is that the diameter of the oriface is many times different between HA and non HA suspensions, but apart from that, the actual damper fitted to the end of the sphere which controls to actual up/down ride and I've always been of the opinion that the various gizmos that control the HA suspension will control them, so if the different sphere is taken out of the equation, doesn't that then take these HA controls out of the system rendering the basic part of the HA inoperative?

I don't know about anyone else, but I'm struggling to grasp what you're trying to say here Alan.

Just the way you've described it doesn't make much sense...perhaps you can have another go, as you might have hit on an important point. (If you're saying what I think you're saying...)

Regards,
Simon

Mandrake · Post by **Mandrake** » 02 Apr 2008, 07:14

steelcityuk wrote:One of the first things I do to a Hydractive Citrroen is add diodes to the ECU and fit a hard/soft status LED that can be seen easily whilst driving. These mods cost pennies to do and it's easy to see if the basic electronics are doing what they are suppose to be doing. All my Citroens have been swapping modes exactly as they should whether they have other faults or not. I find I can clear the ECU codes of both the engine and suspension ECUs using just a simple blink code reader, the simple codes can be read too.

I don't suppose you have a document that lists the blink codes for the Series 1 HA2 ECU and the pinouts ?

I'm still of the opinion that even during Citrerobics the amount of fluid replacement is small. I look at it this way, if there is little to no leak back then there is only 1 pipe into the struts which on a Hydractive Citroen is of a much larger capacity than a non Hydractive Citroen so when you drop the car to it's lowest setting the fluid from the struts goes back along the feeding pipe work to the Hydractive block and maybe as far back as the height corrector. Now you raise the car back to full height and the same fluid you just pushed out of the struts gets pushed back into the struts.

This can hardly be a massive turnover of fluid which if trying to flush the system will take a hell of a long time.

You're dead on here - this is why I believe its so hard to flush air bubbles out of the system on Hydractive models - you have these huge diameter long pipes from the strut tops to the Hydractive block, and then a relatively long skinny pipe from there to the height corrector. The aerated oil has to pass beyond the height corrector to actually escape.

Because of all this you probably have to lift the suspension fully up, then lower it fully down to get enough oil flow to bleed any significant amount - and with anti-sink that means that the suspension is NOT self bleeding through normal daily operation, so gradually accumulates air bubbles if there are any being drawn into the pump......

Has anyone calculated how many CC's of oil there are in the 10mm pipes from the strut tops to the Hydractive block in the front suspension ?

Regards,
Simon

Mandrake · Post by **Mandrake** » 02 Apr 2008, 07:25

A thought that has occurred to me to help us find this "intermittent harshness" problem that a few of our cars experience - a lot of the theorizing is based on the idea of either the electrovalve or the shuttle valve in the Hydractive block misbehaving - for example the valve moving during the impact of a bump causing harshness.

There is a very easy way to confirm this, and all it requires is a set of 4 Standard Xantia strut spheres - simply fit these to the front and the rear suspension in place of the normal hydractive types, and remove the fuse that powers the Hydractive computer.

Result - the car is hydraulically switched in the hard mode all the time but because you have normal spheres fitted you get a normal ride not the hard ride of the "hard mode". Well, almost. The ride will be firmer than a standard Xantia, because the left right connection will be permanently blocked, so it will tend to roll more on irregular surfaces.

But it will be close enough to see if that "harsh" "crashing" ride is still there. I would have tried it myself already if I had access to a set of standard spheres, but unfortunately I don't, and they are too expensive over here just for a test like this.

I'm sure one of you guys who have several Citroen's may have a spare set of spheres that will allow you to try it though...

Any takers ?

Regards,
Simon

Post by **CitroJim** » 02 Apr 2008, 08:11

Mandrake wrote:Any takers ?

I'll be putting normal spheres on the front of my Activa soon Simon, for a test, so that's a start. I won't nitice an increase in roll though as even if the HA computer is inoperative, the hydraulic part of the Activa system will remain operational.

It'll be interesting.

steelcityuk · Post by **steelcityuk** » 02 Apr 2008, 11:21

Hi Simon,

I read the codes on my XM using the 30 pin socket under the steering column, I'm not sure what kind of connector you have on your Xantia. The Xantia I had used an OBD socket but I never tried reading it's codes.

Here's a photo of the XM socket

If you think the info will be useful to you there's a posting here with a PDF that gives the codes -

http://club-xm.com/forum2/index.php?showtopic=960&st=10

Steve.

MikeT · Post by **MikeT** » 02 Apr 2008, 12:28

That looks similar to the connector I have on mine - from memory.

Any idea what the pinouts are and how you activate the tests?

Post by **aerodynamica** » 02 Apr 2008, 13:45

ot really - when the suspension on my Xantia was at its best (and with the correct spheres) I could push the rear suspension right down to the bump stops with one hand let alone sitting on it. Laughing

Even now that the rear spheres a bit low on gas I can bottom it by sitting in the boot. (And I'm only 80Kg) Hydractive 2 is really that soft - and it relies on switching to the much stiffer "hard mode" to prevent the rear suspension from bottoming during acceleration from a standing start.

Yea, now that I think it over some more; in soft mode and XM/Xantia has a greater volume of gas available to each piston of the same axle. If there are 3 x 400cc spheres joined, then that's 600cc per piston. That's more gas than the CX at 500 per piston (in the rest state that is)

It's funny when you consider that this changes from 600 to 400cc available as the firmness reg isolates the centre sphere. Of course it depends also on the amount the gas volume is reduced by compression under the car's static weight (think it's near 50%) mind you the XM has wider struts than the CX (well my early CX) so would feel firmer for the exact same spheres and mass of car (since Cx and XM rear arms are more or less the same part.

Sorry, not really contributing here, just that a future project of mine is to fit hydractive to the CX

and I'm collecting as much info as possible for it..

steelcityuk · Post by **steelcityuk** » 02 Apr 2008, 15:18

The PDF in the link mentioned above gives the circuit diagram to construct the blink code reader and tells you how to activate the blink codes.

Steve.

MikeT · Post by **MikeT** » 02 Apr 2008, 15:21

steelcityuk wrote:The PDF in the link mentioned above gives the circuit diagram to construct the blink code reader and tells you how to activate the blink codes.

Steve.

Oh, good. When I clicked on it, I went to a log in page and I was in a rush. Guess I'll have to register then. Thanks very much

EDIT: I've already made the LED test lead for another vehicle and have to say, they are excellent tools in diagnosing engine management faults.

One thing I should add (as that PDF doesn't seem to mention engine running tests) is to run the engine up to operating temperature and if it's a petrol car with an oxygen sensor, run it at a fast idle of about 2.5Krpm for three minutes to get the sensor up to working temperature

steelcityuk · Post by **steelcityuk** » 02 Apr 2008, 15:26

The connector is identified as having 10 columns labelled as A to J. The square tag end is A and the round pin end is J. The rows are labelled 1, 2 and 3. So in the picture A1 is very top right and A3 bottom right. Column J is missing.

Pin A1 is permanent 12v
Pin A2 is switched 12v
Pin A3 is earth.
Pin E1 is ABS
Pin E2 is Hydractive

If I can find a link to the diagram I'll post it.

Steve.

steelcityuk · Post by **steelcityuk** » 02 Apr 2008, 16:02

I made mine from a cheap Gunsons thing that Halfords were selling off. I find that with the XM timing of opening and closing the switch is important, guessing doesn't seem to work. I'm currently trying to get the Uniscan interface working. The main trouble is getting it to work with a laptop because it need 2 DOS native serial ports.

Steve.