Removing 2.0 TCT engine and other Activa thingies

[CitroJim]

Those cut-in and cut-out pressures are spot-on...

[xantos]

So what's not spot on?

[CitroJim]

So what's not spot on?

That is a very good question....

[xantos]

Right...

So what else could be causing problems? Spheres, pump, high pressure regulator OK, electrovalves working with a slight internal leak (issue?). So could be struts, activa struts, anti-sink valve, security valve? Don't think that height correctors are an issue here... Maybe the suspension ECU is also an issue, but I don't believe that, as everything is basically mechanical operated...

Just hope that I don't get to 140 page, sell the car and then - struck of genius - figure out what was wrong...

[CitroJim]

Hi Xantos,

It will be sorted. We on the FCF don't let things beat us. Especially if you're a member of Team WFA

I think we need to return to basics here and start again with some questions..

1. What is the regulator tick rate? i.e. how long between cut out and cut in. Is there a significant difference between the rates in soft mode and forced hard mode (with F8 removed)? This will help to establish is there is an internal leakage problem.

2. Is there a difference in suspension softness in hard and soft modes when doing the normal tests

3. How long does it take for the STOP lamp to extinguish after say, an over-night stop?

4. is the Activa system working normally? Do you see a 'twitch' from the system on regulator cut-in?

3. If you energetically bounce the front suspension in soft mode with the engine idling can you make the anti-sink valve operate? This is see by the front suspension suddenly going hard and may be accompanied by a regulator tick or series of rapid ticks.

Sorry to ask all these basic questions but it may help us to better get our heads around the issue..

[xantos]

It will be sorted. We on the FCF don't let things beat us.

All the questions have already been answered, but as you said, let's start from the beginning...

1.: Tick rate is about 1,5min. Don't know if there is difference between hard and soft mode, will measure it today.

2.: There is a difference. It's soft when doing the bounce test (engine running), but it doesn't have much back bounce. It stays a bit down and then comes back to the right height. Also I noticed when in hard mode the suspension doesn't bottom out or very rarely.

3.: STOP light goes out immediately no matter how long the car has stood.

4.: Activa is working normally. When I had fuse F8 unplugged it was leaning. F8 connected and it's not leaning. I also have a LED diode connected to the activa electrovalve and I can see it's working properly. It's twitching on cut-in.

5.: Don't know will do the test today.

Other things. The back of the car suddenly drops sometimes when driving. It's farting almost every time (when stopped and engine off) for quite a while, sometimes more than a minute! And it seems like the front is going a bit up, and the back sinks. Activa electrovalve doesn't work in the morning for about 4km driving downhill then it starts.

[Mandrake]

So much has been changed and done I've completely lost track of what it is you're trying to solve...

The stop light going out quickly is unusual but in itself it's not a cause for complaint...

So can we go right back to - what are the complaints that you're trying to fix ? Originally I think your issue was harsh ride - is that still your main issue ?

The "farting" problem seems to be an introduced fault that was caused by some of the changes you've made along the way...

In answer to your points:

1) 1.5 minutes is absolutely fine for the tick rate if it is at least this long both with F8 in and out...

2) What do you mean by "stays a bit down then comes back to the right height" ? Do you mean there is a pause in the rebound before it continues ? Trying to visualise what you mean here... It's also normal for the suspension not to bottom easily in hard mode - that's why there is a body movement sensor attached to the front roll bar that detects sudden changes in height. If you are driving fast and hit a sudden rise in the road that would otherwise bottom the suspension in soft mode the rapid movement triggers a switch to hard mode with its heavy damping which minimises the chance of the suspension dangerously bottoming, and also stays hard for long enough to control the rebound. It's a great feature of Hydractive...

3) Suspicious - I see you have a pressure gauge - did you have it connected to the output of the pressure regulator with the rest of the system disconnected, or did you Tee it in ? If you Tee it in you can test the activation pressure of the pressure warning light on the dashboard. It should be about 100 bars +/- 10 bars.

In fact with the gauge Tee'd in and the car left to sit you should be able to find out why the light goes out so quickly. Another thing you can do with the pressure gauge connected to the regulator is test your accumulator sphere is ok.

As far as I can see only three things can cause the light to go out instantly when starting the engine if the car has been left to sit overnight - either (a) the accumulator sphere is punctured (which allows the pressure to instantly rise instead of gradually build up) (b) the pressure switch is not operating at the correct pressure, or (c) there is a problem with the function of the priority valve.

I'm still suspicious of the valve that you replaced...the fact that it had the wrong number of exposed ports and that you had to modify it to fit worries me.

[CitroJim]

The STOP light going out instantly in an Activa is VERY suspicious. In ever Activa I've ever known it's a wait of between 30 and 40s. They take an age to get up to pressure and I think this must be the first port of call to find out why.

Simon, yes Accumulator is the first place to begin. Then I think suspicion then needs to turn to the security valve. The STOP light sender for this particular function is on the end of the security valve and I'm thinking there's potentially something funny here. If the security valve is not operating as intended it could account for a lot of the strange behavior being experienced.

The fact the STOP light goes out so soon must be investigated..

Another test to do Xantos with your pressure gauge, assuming it's tee'd in, is to see how slowly (or quickly) the pressure falls after switch-off and how quickly it rises up to 170 bar on first engine start after an overnight rest.

[xantos]

Yes it's the harsh ride that I'm trying to solve...

The STOP light doesn't work at all! It should be on when the pressure regulator bolt is unscrewed (no pressure to the system) and it doesn't come on. When there is too little LHM in the tank it doesn't light also... So when I was loosing LHM nothing alerted me until I could feel the steering is going hard

I'm trying to solve both things, harsh ride and stop light as I think they might be related.

Farting is exactly the same even though I changed the anti-sink valve (and slightly altered it - from 4-way connector to 5-way.)

Bottoming started (well at least more often) when I regased the spheres and overgased them (about 10bar).

Bounce test. It's soft when going down but it doesn't bounce back they way it should. When ignition of it's still soft but doesn't bounce back at all. When the car is standing for a while and I open the door (energizing electrovalves) it's hard. I know from the scraped Xantia (hydractive not activa) that it doesn't matter how long it was standing it was soft and bounced perfectly!

Pressure gauge was teed in so that the whole car was presurized.

[CitroJim]

That's interesting about the STOP light Xantos. It might have been 'modified' to hide a problem...

[xantos]

It was working OK. I have problems (with STOP light) since the engine rebuild. Might have connected something wrong, but I had everything marked and didn't touch the security valve apart from disconnecting the "electric" connector. And it's connected I have checked! Is there maybe another one and I connected the wrong one? It would be a pita to change the security valve without the engine removed...

[xantos]

The suspension not different before and after engine rebuild...

[Mandrake]

Yes it's the harsh ride that I'm trying to solve...

I know your pain...

For what it's worth - the only Activa I've ever been in, which belongs to David Hallworth rides beautifully. It's definitely "firmer" damping than a standard Hydractive 2 model but it is NOT harsh in the slightest and does ride very well. After anticipating a much harsher ride than a normal Xantia I was pleasantly surprised at just how good it was...but then that car has had a LOT of care and attention paid to it and is very low mileage too. A real gem. Have you ever ridden in David's Activa Jim ? And if so how does the ride compare to yours or other ones ?

The STOP light doesn't work at all! It should be on when the pressure regulator bolt is unscrewed (no pressure to the system) and it doesn't come on. When there is too little LHM in the tank it doesn't light also... So when I was loosing LHM nothing alerted me until I could feel the steering is going hard

As far as I know the high pressure switch in the priority valve and the level switch at the top of the LHM tank are simply wired in parallel. If you unplug the two wires that go to the level float and short them together the warning light (exclamation point) on the dashboard should light. If it doesn't the switch in the priority valve is probably ok and the fault is further up in wiring where they two are connected in parallel or in the dashboard.

Another thing you could try is to connect an ohm meter across those two wires while disconnected from the level sensor then open the pressure regulator bleed screw - if the priority valve switch is ok you should get a reading.

I'm trying to solve both things, harsh ride and stop light as I think they might be related.

Since the warning light problem started when you had the engine out I think you'll find its just a broken wire somewhere in the engine bay and won't be related to the rest of the symptoms you're seeing like harsh ride. I would get it fixed though as its a little bit dangerous not having the warning light working!

Farting is exactly the same even though I changed the anti-sink valve (and slightly altered it - from 4-way connector to 5-way.)

Although the farting might be a clue I wouldn't necessary spend too much time trying to solve it, I would concentrate on the other faults and it will probably solve itself when they are fixed.

Bottoming started (well at least more often) when I regased the spheres and overgased them (about 10bar).

If you make the suspension softer than it should be it will tend to bottom more easily, so that's not really a fault.

Bounce test. It's soft when going down but it doesn't bounce back they way it should. When ignition of it's still soft but doesn't bounce back at all.

If the engine is not running then after a while the system pressure will drop enough that the suspension reverts to hard mode even though the electrovalve energised. This is normal, because system pressure must exceed suspension pressure for the valve to operate. It can sometimes even change in the middle of a bounce test. For example:

Engine idling, everything up to pressure, stop the engine but then either leave a door open or turn the key back on. (but without starting the engine)

Bounce the front of the car up and down, for a while it will stay soft but then after a few minutes it will suddenly go stiff, I find this can often happen right in the middle of a bounce so that its soft when you press it down but then it goes hard at that point and doesn't return back to normal height. If you then start the engine it will pop up.

Nothing to worry about. All three of my Xantia's have done this - the only thing that varied is how many minutes they would last until going stiff.

When the car is standing for a while and I open the door (energizing electrovalves) it's hard. I know from the scraped Xantia (hydractive not activa) that it doesn't matter how long it was standing it was soft and bounced perfectly!

Not necessarily true - as I described above, when the system pressure bleeds away until it is lower than the suspension pressure (about 120 bars at the front) the hydractive valve will close and revert to soft mode. Typically that would take a few minutes, some cars can maintain soft mode for 5 minutes or so without the engine running but some will not.

An Activa has far more demands for system pressure so I highly doubt an Activa could stay in soft mode with the engine off as long as a Hydractive 2.

Pressure gauge was teed in so that the whole car was presurized.

But when the suspension went hard, how much pressure was left ? If it was less than about 130 bars the front suspension will go into hard mode as system pressure has to exceed suspension pressure by a healthy margin to maintain the valve in the soft mode position.

One of the design flaws of the Hydractive 2 system IMHO is that there is a very small safety margin in system pressure - even un-ladden the front suspension requires 120 bars to lift but the cut-in pressure of the regulator is only 140 bars... If the system pressure is even 10-20 bars too low it won't stay reliably in soft mode.

[CitroJim]

I've not ridden in David's Activa Simon but I know from mine and many others just how lovely the suspension is when all is good. Indeed they are a little stiffer but not outrageously so...

You are right about how critical main system pressure is for the electrovalves to work correctly and if the tick-rate is over 90s in soft mode there's not much wrong with the electrovalves.

My Activa tends to stay in soft for a fair while. Perhaps not as long as a standard hydractive but it's reasonable. I can tell by how long I can leave it and how quickly the STOP light goes out on a restart. Up to about 10 or 15 minutes it's more or less instant.

The Activa system only makes heavy demands on the hydraulics when working and little when the car is stationary. The Activa Accumulator is thee to assist with the demands...

What I have found is that if an Activa ram is leaky it will not work properly so if the Activa system is fully functional that suggests the rams are OK. I test by using a hook to push and pull the Activa linkage rods at their balljoints in the corners of the front wheel arches. A small move of the rod should result in a large tilt of the car..

If you have not done such a test then it's worth doing it. You can do it with the engine off and you should get possibly 6-10 or more tilts out of the system before the Activa Accumulator is empty. Mine seems to go on for ever and ever. Also, the Activa system, because it's only activated when the security valve is wide open, will hold high pressure for days and days as anyone who's disturbed the system on a long stopped car will know to their cost.

If the is a problem with the Activa system in that it's taking lots of pressure when working this could cause the ride problems because the main system is being starved and causing the anti-sink valves to engage and thus effectively locking the suspension beyond what it is in hard mode even.

Because the Activa system makes little demand when the car is at a standstill this problem could be disguised and hidden when doing tests with the car stopped.

Xantos, one more question. Does the car sink when the engine is off and if so, by how much and how quickly.?

[CitroJim]

Just a little off-topic. I've been thinking so hard about your Activa problems today Xantos I notice when proof-reading a paper I'm writing at work I've used the word 'activa' in every place where I meant to write 'active'