That sinking feeling... Xantia VSX

[citroenxm]

Hi Simon,

Hmm, that "bouncing" sounds familiar.. But, it settled, then I opened the valve, and it dropped as quick as though I'd turned the key off...

It doesn't lift/fall/lift/fall all the time, only after I closed the reg screw again..

The Other anti sink valve was from a 1995 M reg car, same year as this VSX car... Does that still not count?

Regards
citroenxm

[Mandrake]

Hi Simon,

Hmm, that "bouncing" sounds familiar.. But, it settled, then I opened the valve, and it dropped as quick as though I'd turned the key off...

It doesn't lift/fall/lift/fall all the time, only after I closed the reg screw again..

But it does stabalize and stay at the normal height for a few minutes without oscillating ?

The Other anti sink valve was from a 1995 M reg car, same year as this VSX car... Does that still not count?

Sorry, nice try! The difference is between Hydractive 2 and Standard models, and is nothing to do with the year... (I have the internal diagrams of them in front of me and they're quite different...pity I don't have a scanner, or I'd post them up)

Regards,
Simon

[mrjohnson]

Mandrake,

If you have, or can borrow, a digital camera then you can photograph documents and email them.

Regards

Martyn

[citroenxm]

Hi Simon,

Yes it stops oscillating ... Then open reg screw, SINK....!

Close back up, back end back up.... oscillates, then settles...

Worth a try, Citroen didn't half make it expensive for them selves as far as common parts on Xantias go..

Well cant have it all, I'll have to look for some M 95 VSX's breaking, Ebay etc

Regards
citroenxm

[Mandrake]

Mandrake,

If you have, or can borrow, a digital camera then you can photograph documents and email them.

Regards

Martyn

Hi,

Yes I do have a digital camera but I've found it very difficult in the past to get satisfactory pictures of an A4 sheet of paper, and the end result isn't all that good compared to even a cheap scanner, mainly due to optical distortion, focus and lighting issues. I'll give it a go on a few of the more interesting pages of the anti-sink info though, and see if it comes out usable...(I suspect the cutaway diagrams won't be clear enough)

Regards,
Simon

[ekaftan]

My beige Xantia has a broken HA2 ECU so its stuck in hard mode (ecu on its way, thanks phil . That one cycles every 15 seconds but passes the 'sit on trunk' test perfectly so that one must have a leak on the sphere or one of the electrovalves, right?

Quoting myself again..

I fixed an annoying LHM leak my 94 (late, with antisink) Xantia had. The leak was at the pump, where the pipe to the accumulator is fitted.

Every cycle a drop appeared on the junction. That added up to half a liter a month. That junction has a small nut, a bit (20 mm) nut on what appears to be a non return valve and an oring.

I replaced the oring and cleaned the surfaces. First try I made it worse. Second try I did it ok and fixed the leak.

It know cycles much slower. Not as good as the green Xantia, but much better. I am not sure yet, but that also seems to have made the rear end less likely to make weird reactions when I drive over a bump and the suspension reaches maximum extension.

It seems like every little thing must be perfect. Every small leak starts some kind of chain reaction and the symptoms appear somewhere you dont expect it.

[Mandrake]

Ok,

I ended up doing the whole antisink book (with a camera) as its only 10 pages. The raw photos didn't come out too well but after some (somewhat tedious) image processing they look fairly good.

I suggest those that want them download their own local copies and archive them as I can't guarentee they'll stay there....

http://homepages.igrin.co.nz/simon/imag ... /antisink/

Regards,
Simon

[citroenxm]

Mandrake,

WOW that is some wonder full information... I'm gonna try and find a VSX anti sink valve now and fit it to see what happens next..

Thankyou for you time, its been a great help.. May the help (either way) continue

Best regards
citroenxm

[steelcityuk]

Nice work Simon! Very useful. Is the info from a dealer service manual?

Finally fitted the last 2 spheres to the Xantia (rear strut ones) on Saturday. The ride's slightly better but not much. Next thing is to trace the fault causing the pressure regulator to cycle too often and also try disconnecting the HA valves so that I can tell if the car is going into soft mode. If not maybe I can rig up some kind of manual switch to see if the ECU is not switching in to soft mode or the HA valves are faulty.

Steve.

[steelcityuk]

For the last couple of days the Xantia has been riding better than normal since fitting the new rear spheres. However this morning it was back to it's old self. So I guess I know that there's some kind of fault with the HA2 system, just at this stage I'm not sure if it's mechanical or electrical. Maybe if I can bypass the ECU controlling it and force soft mode then after a few days I'll know which system is at fault, then I'll have to narrow it down from there.

Any suggestions?

Thanks.

Steve.

[ekaftan]

For the last couple of days the Xantia has been riding better than normal since fitting the new rear spheres. However this morning it was back to it's old self. So I guess I know that there's some kind of fault with the HA2 system, just at this stage I'm not sure if it's mechanical or electrical. Maybe if I can bypass the ECU controlling it and force soft mode then after a few days I'll know which system is at fault, then I'll have to narrow it down from there.

Previous owner did that to my car. He burned te HAS2 ECU's output transistors doing it Dont...

Start by checking if the elevtrovalves are being energized. If they are, you'll here the buzzing when opening a door.

[steelcityuk]

I was thinking more along the lines of disconnecting the ECU from the HA valves and powering them via a switch. Or using a low wattage bulb/LED to signal when the valves were powered by the ECU. Working in IT I'm aware of how delicate semiconductors can be.

[ekaftan]

I was thinking more along the lines of disconnecting the ECU from the HA valves and powering them via a switch. Or using a low wattage bulb/LED to signal when the valves were powered by the ECU. Working in IT I'm aware of how delicate semiconductors can be.

Simon (mandrake) told me how to do it a couple of weeks ago...

Valves need 12 volts to open, but only 3 or 4 to stay running. So you have to rig a switch in series with a 15ohm resistor and a normally open momentary closed switch that bypasses the resistor.

To open the valves you turn on the switch, sending 3 volts to the valves and the touch the other switch to send a 12 volt pulse. To close, turn off the switch.

It will make you car softer if the problem is electrical, but will do nothing if the problem is hydraulic. And it will make the car too soft for sporty driving or for large potholes (The ecu closes the valves if the car is going to bottom out and you'll erase that feature)

So, maybe you should instead of rigging the valves open, try to monitor them. Connect a LED in series with a resistor to the valves positive feed and see if the ECU tries to open and close the valves. Mandrake's page has some pictures of this. And he also will tell you which resistor to use, I forgot

[Mandrake]

Yeah,

The electrovalves require the full 12v to switch on, but they can't handle this amount of power dissipation continously without overheating and burning out.

That's why the ECU gives them half a second of full voltage and then drops back to 25% PWM thereafter each time they switch on.

So just running them directly off 12v for long periods of time has a high risk of damaging them...

(The comments about the car being less safe to drive when the ECU can't switch back to hard mode for braking/cornering, large dips etc is also valid)

Regards,
Simon

[ekaftan]

(please ignore this post. pressed the worng button and cant erase it)