Xantia Activa drops on key-off

[djadams]

A couple of things my Activa does differently to my previous more basic Xant are:

• If you stop the engine with the door open, you get a sudden drop of the front suspension by 25-40 mm or so.
  Also, during low speed manoeuvring, the steering will sometime go a little heavy, as though the main accumulator is running out of puff.

So - I thought the accumulator probably needed replacing, but when I check the "tick rate" it's not so bad, maybe a minute or so with the car running but not "doing" anything.

Any thoughts on what to check? I'm hoping the steering issue isn't excessive leakage from the steering rack, though that would not surprise me (most rubber parts on this car are now more akin to bakelite).

[wurlycorner]

My Activa has the steering go heavy during low speed manoeuvring too. It's annoying and I don't know what it is yet, but haven't got any concerns about it being the rack...

Like you, I thought it must be the main accumulator and changed that, but no difference. I'm in the process of changing various other spheres and will see what it's like after that.

Suspension dropping with door open and key off sounds like either the electro valves aren't operating at the front, or your front anti-sink sphere is knackered?

[Mandrake]

Yep, sudden height changes when you turn the key off or on will be an electrovalve problem - most likely the internal diode is faulty so can be fixed by doing the external diode mod. So if that has not been done yet I would try that first. (Lots of info on the forum about this mod) Remember an Activa has three electrovalves not the two of Hydractive 2.

Sometimes it can just be high resistance to the coil internally though which would require a replacement electrovalve - but in that case you should be able to measure an obvious difference in coil resistance between good and bad electrovalves with a multimeter. A good coil should be 4.8 ohms. Occasionally it might be a mechanical problem with the pintle valves inside not sealing but that's much less likely than an electrical problem.

[Xaccers]

Spheres have nothing to do with steering, its fed directly from the pump and relies on high flow of lhm so make sure there are no air leaks in the reservoir to pump hose.
It may just be the lower universal joint on the steering rack needs lubing.

The anti sink valves rely on enough back pressure from the spheres to close so if you have an internal leak back to the reservoir the pressure may not be enough for the valve to close quickly.

[djadams]

Yep, sudden height changes when you turn the key off or on will be an electrovalve problem...

This makes lots of sense - it being hydractive related rather than anti-sink related may explain why it only happens with the door open. If you key off, then open the door, all is fine.

Spheres have nothing to do with steering, its fed directly from the pump and relies on high flow of lhm so make sure there are no air leaks in the reservoir to pump hose.

Aha! Good point well made! Had forgotten about the completely separate power steering pump elements!

Right - LHM feed hose replacement and possibly “10 minute octopus mod" may well be the answer here - the sudden increase in flow to the pump during low speed manoeuvres may well draw in more air, resulting in decreased assistance to the steering! Good stuff, thanks for setting me straight...

The anti sink valves rely on enough back pressure from the spheres to close so if you have an internal leak back to the reservoir the pressure may not be enough for the valve to close quickly.

Interesting - could this still be electrovalve related, or would we be talking strut wear here?

Thanks for the pointers gents, really appreciate it!

[Xaccers]

It could be a leaking electrovalve on the hydractive block so when you're in soft mode it leaks back to the reservoir but in hard mode it doesn't.
One way to test is to remove the fuse that feeds the valves so you're in permanent hard mode then see if it drops.
I'm sorry I don't know what fuse in the engine bay it is though.

When you're doing low speed manoeuvres the engine revs are likely to be low meaning the pump is being spun slower so the volume of lhm getting to the power steering is less, but if the amount of air getting in stays roughly the same then there's more air to liquid so the power steering will struggle.
On most Xantias the feed and main return pipes are bonded side by side down between the reservoir and engine so replacing the feed pipe on it's own isn't possible, however it can be bypassed with a new silicon pipe, the sort that boy racers use, with an 8mm inner diameter if memory serves (measure the reservoir spigot diameter and the pump spigot diameter). Wrap some duct tape around the ends of the pipe so it doesn't get damaged by the jubilee clips being done up. Don't try and route the new pipe the same way as the old one goes, the elbows are too tight, just run it across the front of the engine and use cable ties to secure it.

[Hell Razor5543]

According to handbook version X2-GB-4001, F3 (dashboard, 10A) is the fuse that manages Hydractive suspension, and only manages the suspension.

[Mandrake]

According to handbook version X2-GB-4001, F3 (dashboard, 10A) is the fuse that manages Hydractive suspension, and only manages the suspension.

Hmm in both my old VSX and my Exclusive the Hydractive fuse is in the engine bay fuse box behind the battery...(I don't recall the number but can check on the car tomorrow)

Edit: F8 in the under bonnet fuse box according to the wiring diagram for my Xantia.

[Xaccers]

I believe they are different between S1 and S2. Jim tried pulling the fuse in the engine bay on Juliet (S2) and it didn't make a difference to the hydractive.

[Sl4yer]

Won't it stay in soft mode for 30 seconds if the door is open when the engine is switched off?

[Mandrake]

Won't it stay in soft mode for 30 seconds if the door is open when the engine is switched off?

No its 30 seconds with the doors closed, 10 minutes with any door open. Closing and reopening the doors gives you another 10 minutes.

[Mandrake]

I believe they are different between S1 and S2. Jim tried pulling the fuse in the engine bay on Juliet (S2) and it didn't make a difference to the hydractive.

Hmm. The wiring diagrams are pretty clear about it, and are the correct diagrams for my exact model and RPO number. I'll try pulling the fuse tomorrow and see what happens.

[xantos]

Well on my Activa S2 the fuse for hydractive is definitely F8 in the engine bay...

Also having trouble with drop-off when engine stops (electrovalves working). I suspect that I have an internal leak on the suspension cylinders. When the car is stopped and I do the bounce test the car goes down and it doesn't return up. If the engine is working it bounces nicely...

[Hell Razor5543]

I know that the info I posted appears to be incorrect, but that is also why I posted the manual version number (and, by the fact it begins X2 suggests it could be for a series 2 Xantia) The last page shows a print date 04/2000. Page 118, F3, 10A, under dashboard.

[Mandrake]

Also having trouble with drop-off when engine stops (electrovalves working). I suspect that I have an internal leak on the suspension cylinders. When the car is stopped and I do the bounce test the car goes down and it doesn't return up. If the engine is working it bounces nicely...

Have you checked the return line (rubber hose) from the electrovalves for excessive leakage flow ?

Disconnect the hose and plug the end to stop it siphoning the LHM tank empty (!!) then connect a clear hose from the electrovalve into a measuring jug.

Operate the suspension between soft and hard modes, (engine running versus engine stopped and doors closed for >30 seconds) and see if you see any significant flow.

At most you should only see a tiny "spit" of oil when the valve switches states with no flow at all when constantly in soft or hard. Any constant flow is a faulty electrovalve.

Edit: the Activa has a third electrovalve for the balancing sphere and I don't know whether its possible to cause this to switch states when the car stationary - probably not.