I am also P£$$$ed with hydractive

[CitroJim]

What about series 2 cars?

They use the speed sensor on the gearbox that drives the speedo and engine ECU...

...when the valves do work the suspension is fine.

That again points to low system pressure...

I hear Miss Hydractive has been seen out and about with another car.

She likes a bit of high pressure does our Miss Hydractive...

[davetherave]

Well I only have a short 1300 mile trip on tuesday so it will be a good test...
I wonder if the hydraulic pump belt was not tensioned enough, perhaps causing low system pressure, due to the stupid belt arrangement, you have to pull the pump up with one hand and tighten a bolt with another to get the tension set.
When i make myself a pressure guage I will be re shimming the regulator as I have a few spares in stock now.

[Deanxm]

The pump bracket has a squar cutout to take a 1/2" socket, connect the socket or bar to the alloy mount and tension the belt like that and then do the 13mm locknut up, you wont get enough tension by hand Dave, you would get juddery steering if the belt slips though.

D

[Mandrake]

You may well be right but certainly hydractive one will not trigger hard mode without speed sensor input, there is only brake pressure switch, steering angle input, body movement and speed sensor, the ecu will remain in soft mode with ignition on and 0 speed for pressure equalisation during loading and unloading, you can wiggle the steering wheel and bounce the car as much as you want it wont trigger firm mode unless it see's a speed of over 8kmh? cant remember now, later H2 may have been able to tell if a sensor is open circuit or a dead short or if it is telling porkies, the speed sensor in early cars is fitted inline to the speedo cable above the gearbox at the bulkhead, if you unplug the sensor from the cable it is still connecetd electricaly but will not detect movement of the car, yes the speedo will not work unless you use a joiner or second speed sensor to plug in place but it will tell you very quickly if you have pressure problems or electrovalve driver issues.
Works fine with mine anyway, disconnecting the body movement sensor (mechanicaly from the arb) will also prevent switching to firm on undulating roads whilst giving firm mode in the corners but if your roads are really rough you do risk bottoming out on big bumps.

D

Sorry I had assumed the original poster was talking about a Xantia, which are all Hydractive 2. Hydractive 1 is a different beast and has quite different behaviours, so you could well be right on Hydractive 1.

On Hydractive 2 a faulty speed sensor is determined by inference - the main way is if the accelerator is depressed more than 15% for over 30 seconds and the speed sensor registers nothing, (no pulses) it is assumed to be faulty. So whether you disconnect it electrically or mechanically makes no difference, it is assumed to be faulty and the vehicle speed assumed to be 100Km/hr (low turning thresholds for the steering wheel before triggering hard mode etc) for safety. If the speed sensor starts working again for at least 20 seconds it will start believing its input again.

There are various clever ways to detect by inference faults in all of the various sensors by comparing the data from them and checking them for consistency and believability, all detailed at the table near the end of this document: (page 70)

http://homepages.igrin.co.nz/simon/imag ... ive_II.pdf" onclick="window.open(this.href);return false;

(alter the 'e' in citroen to the standard lower case e, and the C to lower case)


One sensor you can disconnect to keep the car in soft mode a lot more is the throttle sensor - I did this on my Mk1 Xantia for a few months and it prevents the car switching to hard on take-off from a standstill - the rear squats a lot more but at least you don't get that bumpity ride for 5 seconds every time you accelerate from a standstill over broken road surfaces. It also prevents it switching to hard when you stomp on the pedal at speed. (Albeit with more rear body squat obviously)

It has no effect on the car going to hard when braking or cornering though, which is good, and still safe. Nor does it affect the anti-roll bar sensor. So for anyone who prefers a softer ride more often and doesn't drive like a maniac the throttle sensor (plug up behind the accelerator pedal on the firewall) can be safely unplugged, the only real downside is a lot more squat under acceleration. On something like a V6 it probably wouldn't be a good idea to disconnect, as the squat is likely to be ridiculously bad if left in soft mode I might try it for a few days for a laugh...

[davetherave]

Dean you are a genious, or I am an idiot! Cant beleive I didnt realise this!
Ive just nipped out and tensioned it
The belt is better tensioned than ever now!!

That looks to be an interesting document simon, ive saved it to read at a later date!
Dave

[myglaren]

I have been attempting to access that .pdf without success, used Tinyurl to overcome the word censor, the final link to the pdf would not respond in Firefox, froze Flock completely, took ten minutes in Opera but finally did open.
Chrome accessed it straight away.

In Firefox it appears to have been the Foxit plugin that crashed but didn't issue an error report for over half an hour

here is a modified link using Tinyurl that overcomes the word censor problem.

[Deanxm]

That PDF Is brilliant Simon, thanks for sharing.

Dave i had my xm 2 years before i found that, struggling trying to hold the bloody pump up tight with one arm and do up the nut that was now abscured by the tensioning hand drove me insane, i could never get it tight until i saw that socket hole in the bracket one day.............. really one of the easiest belts to do since i found that.

D

[davetherave]

well drove from norwich to dartford toll bridge and the suspension was solid. Turned car off and on and it was fine all the way to dover.
Something is definatly wrong!

[Mandrake]

well drove from norwich to dartford toll bridge and the suspension was solid. Turned car off and on and it was fine all the way to dover.
Something is definatly wrong!

Define solid - do you mean it was stuck in hard mode, (stiff, heavily damped, but not bouncy) or was it almost rigid with severe bounciness ?

In the former case it might have been stuck in hard mode for some reason, in the latter you might have had a sticky height corrector causing one end of the car to be riding on the bump stops!

[davetherave]

definatly stuck in hard as when i have done bounce tests there is zero travel in the suspension.
I am wondering if it could be the speed sensor as last time I lexiated this came up as an intermittent fault.
I will lexia again now its been to france and back to see what its come up with this time.

[addo]

Age of them aside, I serious wonder if there is a dead corner sphere, and a sticky/intermittent electrovalve. Two faults for the price of one.

[davetherave]

But why would it ride beatifully then go into hard? It could be sticky electrovalve, but surely not both at the same time?

[addo]

Well, when the electrovalves are working, you are gaining suspension "compliance" from the centre sphere, which is essentially undamped and quite high pressure. When the valve shuts out that sphere, you are back to one deadie. And that, with a sturdy anti-roll bar, is enough to make it very harsh.