Anti sink not working

Stempy · Post by **Stempy** » 24 Feb 2006, 18:53

Cheers, I wondered if one side of the coil would be grounded, that being the case it's fairly obvious.

Mandrake · Post by **Mandrake** » 24 Feb 2006, 21:40

The coil resistance is about 4.7 ohms, in parallel with the diode, so testing whether the diode is actually intact can't be done with a simple ohm meter as it will read the same both ways.

However (assuming you have the electrovalve out of the car) if you use a 12 volt battery and a 10 watt 15 ohm resistor it can be established - connect the battery via the resistor to the electrovalve and measure the voltage across the electrovalve terminals with a volt meter - with the correct polarity you should see about 2.5 to 3 volts. With the wrong polarity it will be less than 1 volt.

This is your sign that the diode is ok. If the diode has gone open circuit it will read 2.5 to 3 volts both ways around. As Anders says, the Anode should go to the negative, as it is connected in reverse to conduct the back EMF spikes.

It may be possible to get the electrovalve out without taking the whole unit - if you remove the spare wheel carrier and drive the back of the car up on ramps there is quite a bit of room to work. When you depressurize remember to open the regulator bleed screw (last) as the electrovalve has the FULL system pressure on it, it is not fed via height correctors, thus it will still be under pressure if you just lower the suspension.

You remove the low pressure overflow pipe from the electovalve and block off the hose (otherwise your LHM tank will empty itself on the ground

) and then use a 16mm socket drive on the end to undo it. Be careful as it can be tight, and it is possible to break the electrovalve, as bernie discovered.

Another way to approach this whole thing though, would be to measure it from the computer end, as I have the pinouts for it. If you lift the cover off the ECU box in the engine bay you'll see the computer nearest the middle of the bay has two plugs on it - this is the Hydractive computer.

Both plugs have a wrap around wire clip that you'll need to unhook and remove and then you can unplug both plugs together. The *white* plug nearest the back of the engine bay is the one of interest.

Pin 1 is the postitive supply to the front electrovalve, and Pin 2 is the positive supply to the rear electrovalve. Pin 8 and 15 are earth.

Using this you can test the diode built into both electrovalves using my battery and resistor method above, but from the comfort of the top of the engine bay

If the diode is faulty you can't replace the original one as its imbeded into the electrovalve so you'd have to connect one externally. By probing with a pin I was able to find the two white wires coming from that plug are pin 1 and 2, so it would be possible to splice a diode neatly inside the ECU box and tape it up rather than putting it under the back of the car - you'd just need to find which wire was earth (going to 8 or 15) to be able to finish it.

Regards,
Simon

Stempy · Post by **Stempy** » 24 Feb 2006, 22:15

My list of jobs to do on this Xantia increases by the hour

I will attempt to discover the whereabouts of the suspension ecu as nothing is where it should be on the V6. If I have to wire in a diode or two then I might add a couple of LED's in the cockpit while I'm at it. Knowing the pinouts from the ecu makes that a whole lot easier.

Mandrake · Post by **Mandrake** » 24 Feb 2006, 22:27

Stempy wrote:My list of jobs to do on this Xantia increases by the hour I will attempt to discover the whereabouts of the suspension ecu as nothing is where it should be on the V6.

Hehe... here is a picture of what the Hydractive computer looks like in my car:

http://homepages.igrin.co.nz/simon/imag ... ngine2.jpg

It's the silver coloured box near the left with two plugs connected to it. Although it may be in a different location it should be the same unit...

If I have to wire in a diode or two then I might add a couple of LED's in the cockpit while I'm at it. Knowing the pinouts from the ecu makes that a whole lot easier.

I've got an LED connected to the front electrovalve on mine at the moment for diagnostic purposes too - and I used 100 ohms for the resistor value.

Regards,
Simon

Stempy · Post by **Stempy** » 24 Feb 2006, 22:41

I used to have one just like that, 2.0i Auto in blue. I sometimes wish I'd kept it but I went for the 3.0 as I found the 2.0 seemed to struggle a bit to pull the autobox. I just pay for it now in fuel. Good job I have a van for work so it only gets used at weekends.

Nice clean engine bay BTW, I have an ECU box very similar to that only it has extra boxes in there, so I now know which one is the suspension ECU.

Mandrake · Post by **Mandrake** » 24 Feb 2006, 22:53

Stempy wrote:I used to have one just like that, 2.0i Auto in blue. I sometimes wish I'd kept it but I went for the 3.0 as I found the 2.0 seemed to struggle a bit to pull the autobox. I just pay for it now in fuel. Good job I have a van for work so it only gets used at weekends.

I would love to have a V6, but there are so few of them here that I wasn't able to find a single one for sale. The ones that I did find that didn't want to sell wanted nearly twice what I paid for the 2 litre one...

Nice clean engine bay BTW, I have an ECU box very similar to that only it has extra boxes in there, so I now know which one is the suspension ECU.

I just remembered that the info that I was looking up I printed out off the net in the first place, so here is the link:

http://www.stevenbraud.demon.co.uk/manu ... to_73.html

Regards,
Simon

Stempy · Post by **Stempy** » 26 Feb 2006, 20:07

Well I managed to get out long enough to bleed the rear brakes but it was too cold to stay outside for long. There was certainly air in there and the braking has improved somewhat, but I reckon there's still a bit more that I haven't got out.

I forgot that the rear axle needs to be loaded for the fluid to flow to the rear brake circuit so it took a bit longer than I anticipated. I'll have to have another go sometime soon and do the fronts as well.

bernie · Post by **bernie** » 26 Feb 2006, 20:35

This is my temporary job

Mandrake · Post by **Mandrake** » 26 Feb 2006, 20:56

bernie wrote:

This is my temporary job

Oooh errr....

Do you have those poor little LEDs connected directly without any feed resistor ? Have they expired yet ?

I have one green LED connected to the front electrovalve via 100 ohms, and its plenty bright enough...

Regards,
Simon

Stempy · Post by **Stempy** » 26 Feb 2006, 23:14

Well, I finally got around to fitting a couple of diodes in the electro valve circuit and wow, she's back to her old floaty self.

I actually pulled out the suspension ECU, split it open and soldered the diodes inside to the relevant pins to help keep things tidy, sealed it all up again with a bit of silicon and away she went.

Not only that but I also fixed my rear electric window, so that's another two jobs to tick off the list.