Great fun video - How to shake a cocktail!
Back to the car...
This is well worth downloading and reading:
http://www.citroenkerho.fi/xantia/pdf/t ... kaopas.pdf
It's written by one of our members (Gabor), and describes really well a number of the systems used on Citroen hydropneumatic vehicles, especially suspension.
From your RP number 4823, your vehicle was built 22 Jan 1990.
The suspension system is Hydractive I (originally known as just Hydractive, but then Hydractive II arrived at RP5929 in Feb.1993).
I and II are similar, but have important differences, as Gabor's article explains.
Your H.I system has one electrovalve (II had two), located on a bracket on the right-hand rear section of the front subframe.
Under instructions from the suspension ECU, it switches the Centre spheres (one at front, one at back) in and out of the hydraulic circuit.
When electrovalve is OFF (not energised) the centre spheres are OUT of circuit, and the suspension is Firm.
When electrovalve is energised, the centre spheres are switched into the hydraulic circuit, and the suspension is Soft.
To fit an indicator lamp (or LED) - to tell when the electrovalve is on/off - you can tap into its supply wiring either at
1 - Under the car at the EV itself (two electrical connections, one is chassis earth, the other is supply)
2 - At the suspension ECU. On your car its the 15way Black connector, pin 9.
On the circuit diagram, it shows a yellow wire going to pin 9 (but check!....a needle pushed through the cable insulation will help identify connections).
>>> Note: Later EVs were of a different design (the solenoid was built in to the EV body; early ones were separate). The later type were NOT energised by a simple constant 12v DC, but received 12v for 0.5secs, followed by what looks like around 3v "holding" supply, which is actually a 1000Hz pulsed (PWM) supply, which reduces heat in the EV coil.
To be safe, and avoid damage to your EV, DO NOT feed it with a constant 12v, even for test purposes, until it can be confirmed how these early EVs were supplied.
You can judge this for yourself: Put a voltmeter on the EV supply (connections as above), and see what it reads. If 12v followed by around 3v, then it's the later pulsed supply. This can usually be heard as the valves buzzing. <<<
Test drive:
You have two choices: AUTO and SPORT.
In Sport mode, suspension will lock itself into Firm mode, but only above 30km/h (18mph). Below that, it will be Soft.
In Auto mode, system will be soft, and will only switch to Firm when the ECU tells it to.
There should be a clear difference in ride between Soft and Firm. If there isn't, then your Centre ('Hydractive') spheres need renewing, or something isn't working electrically or hydraulically. It's these two centre spheres that provide the extra softness.
BUT, and most important . . . Your photo of the front sphere . . .
Yes, the cap on the sphere is the factory fitting, and is not a refilling valve, but is where one would screw in.
Your photo shows the sphere top edge in contact with the bodywork panel above it. This should not be, but there should be an 8-10mm gap there.
This is a clear sign that the rubber-centred strut top mount is beginning to break up (the rubber shears) and is allowing the sphere and sphere mount to push upwards; if left unsorted, massive damage can occur, if the strut top bursts through the bonnet.
Front strut top failure.jpg
Normal clearances are like this:
Front sphere clearances 2.jpg
Second photo also shows a Tecnosir regassing valve (with its green dustcap) installed.
Check the clearances with the car at Normal height.
If strut tops are looking tired/stretched, avoid putting the suspension on Highest (it strains the tops) and avoid rough roads. Get the tops replaced quickly, because complete failure can be very sudden.
Plenty of info on our site about strut tops, availability, replacement, rebuild possibilities, and so on.
Hope helpful.
Keep us updated how you get on.
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