Fast Regulator Tick in Soft Mode (Now Solved!)

Unread post by **CitroJim** » 23 Aug 2009, 09:18

xantia_v6 wrote:Try this

Thanks Mike, very much appreciated

That's now stored awayin a safe place on my server!

Unread post by **CitroJim** » 23 Aug 2009, 11:06

xantia_v6 wrote:BTW, I just have a feeling that there is a big red herring in the information we have so far... but I can't put my finger on it. I think it would be good to find a way to confirm that the HA valve leak rate is actually caused by the shorter waveform.

I've been thinking the same. As soon as I have time I'll disconnect the leakage returns from the electrovalves and see how much is coming out in soft mode. The valves, in theory at least, should only spurt a bit whilst changing modes. When in either hard or soft mode the leakage return is sealed.

If it's not electronic then what else can it be except the valves? I still cannot believe both are leaky and leaking by the same amount

especially as the rear hydractive sphere block has been replaced recently and in doing so, the electrovalve.

Shame is, I cannot remember if this was a pre-existing fault before the rebuild and in any case, because the original valve was corroded and leaking from its O ring seal in soft mode originally, this leak might well have masked any problem.

xmexclusive · Unread post by **xmexclusive** » 23 Aug 2009, 14:03

Hi Jim

My VN05N document is broadly the same but the 2008 version.
Only major difference is that all the different leg configerations are no longer available just the stand vertical bent leg option.
I think the Link is www.st.com
If you think I am raising "Scarlet Sharks" just tell me and I will go away.

John

Unread post by **CitroJim** » 23 Aug 2009, 21:36

xmexclusive wrote: If you think I am raising "Scarlet Sharks" just tell me and I will go away.

Not likely John

I'm here and wide-open to any thoughts and ideas on this problem so keep 'em coming!

xmexclusive · Unread post by **xmexclusive** » 23 Aug 2009, 22:19

Hi Jim

One of my current projects is to make up a pair of suspension ECU test leads. This will allow me access to monitor LED's, switch in protection diodes, swap front/rear electrovalve drivers and simulate most of the ECU inputs. That should help track down individual effects to specific causes. The logic is simple, try one thing at a time, to work systematically through the options. When I finally get a Lexia I will be able to read the ECU's as well.

John

DickieG · Unread post by **DickieG** » 23 Aug 2009, 22:40

Further to simply a Lexia you want to get the breakout leads/harnesses to go with it so that you really can test each individual component.

xmexclusive · Unread post by **xmexclusive** » 23 Aug 2009, 23:00

Hi DickieG

Been watching for sets of breakout leads that come up for sale for a few years now. Not been lucky so far apart from a few odds and ends.

John

Unread post by **CitroJim** » 25 Aug 2009, 20:34

More tests carried out this evening...

I have been fighting a shoal of red herrings on this one

Although I did not have a spare normal HA ECU I did have a good spare Activa HA ECU so thought I'd give it a try after looking at the relevant circuuit diagrams to check all wires went to the same place and did the same jobs on each ECU. They do but they're not directly interchangable; the normal ECU has white and black connectors whilst the Activa ECU has white and green connectors. The balck and green connectors have different indexing lugs which make them non-interchangable but if you carefully shave off the middle index lug on the green connector they can be swapped for test purposes.

Guess what.. Exactly the same fast tick rate and exactly the same wave form

So unless that ECU has exactly the same fault (very unlikely) it's something else.

I bit the bullet and disconnected the leakage returns from the electrovales and lo and behold they're both leaking like crazy in soft mode; enough to fill a litre jar with LHM in just a couple of minutes

They are literally running full-bore

So, that's it. I have two duff electrovalves

I must now save my pennies for two nice shiny new ones

My apologies for creating a long thread out of a red herring. I fell into the trap of trying to look for an electronic problem as I just could not believe that both valves could be faulty.

You learn something new every day with these cars

Unread post by **xantia_v6** » 25 Aug 2009, 21:29

Jim,

It may be that this is how electrovalves go at 150,000 miles. I know the rear electrovalve on my MK1 dribbles happily from the return hose (don't know about the front).

On the other hand, we don't have an explanation yet for the different waveforms.

Unread post by **CitroJim** » 25 Aug 2009, 21:38

Yes, maybe the valves are simply worn out. They will have switched an awful lot of times in 150,000 miles...

xantia_v6 wrote: On the other hand, we don't have an explanation yet for the different waveforms.

My next piece of reasearch. One telling difference between the Activa and the V6 is that the Activa has quite a tired battery whereas the V6 has a brand new one and all tests have been carried out with the ignition off on both cars. Maybe the mark:space ratio does change to compensate for battery voltage.

Only one way to find out

vince · Unread post by **vince** » 25 Aug 2009, 22:04

CitroJim wrote:More tests carried out this evening...

I have been fighting a shoal of red herrings on this one

Although I did not have a spare normal HA ECU I did have a good spare Activa HA ECU so thought I'd give it a try after looking at the relevant circuuit diagrams to check all wires went to the same place and did the same jobs on each ECU. They do but they're not directly interchangable; the normal ECU has white and black connectors whilst the Activa ECU has white and green connectors. The balck and green connectors have different indexing lugs which make them non-interchangable but if you carefully shave off the middle index lug on the green connector they can be swapped for test purposes.

Guess what.. Exactly the same fast tick rate and exactly the same wave form So unless that ECU has exactly the same fault (very unlikely) it's something else.

I bit the bullet and disconnected the leakage returns from the electrovales and lo and behold they're both leaking like crazy in soft mode; enough to fill a litre jar with LHM in just a couple of minutes They are literally running full-bore

So, that's it. I have two duff electrovalves

I must now save my pennies for two nice shiny new ones

My apologies for creating a long thread out of a red herring. I fell into the trap of trying to look for an electronic problem as I just could not believe that both valves could be faulty.

You learn something new every day with these cars

Look at it this way Jim...

You were right in your first diagnosis

Unread post by **Peter.N.** » 25 Aug 2009, 22:55

...and you won't forget will you - I probably would, but I'm sure you wont.

Stempy · Unread post by **Stempy** » 26 Aug 2009, 12:19

Is it possible that neglected LHM change intervals would cause the valves to wear more quickly. I know nobody here would do such a thing, but previous, less mechanically sympathetic owners can't be accounted for. I wouldn't mind betting that even a car with a full service history would be down on its fair share of hydraflushes.

xmexclusive · Unread post by **xmexclusive** » 26 Aug 2009, 13:07

Hi Jim

In soft mode the Electrovalve should be fully energised. If it is not fully energised because of an intermittant waveform, it is possible that it may open but not hold enough to be able to fully compress the electrovalve spring so not close the return valve. That would explain your return flow symptoms. Operating in this mode for a long period of time is going to have very high flow LHM rates through the return valve orifice. More generally for cars if the LHM is dirty particles passing at high speed will abrade the valve surfaces leading to leakage problems. On this basis new electro valves will cure the car but not solve the basic problem with the ECU. I think we still need to know more about suspension ECU's before we can be certain about testing, fault finding and repair.

John

Unread post by **CitroJim** » 26 Aug 2009, 19:30

Hi John,

I'll be delving more deeply into this; I've got the bit between my teeth now

Not only is the valve electrically operated into soft mode but it is also assisted to fully switch over by hydraulic pressure. If you look at the hydractive block physically and study the theory, it will be seen that LHM at system (straight from the security valve) pressure is present under the valve. This will assist the shuttle in moving to the soft position as soon as the coil is energised. The valve is held in the hard position by a strong spring that system pressure alone cannot overcome; it's the combination of pressure and magnetism that does the trick. As the valve shuttles to the soft position, the leakage return is fully shut by a needle extension to the shuttle operating on a ground seat. Wear on this needle and its seat could well arise from neglected, dirty LHM. The way the valve is constructed, it should only ever just spurt a bit of leakage on mode changes as the return is effectively blocked in either mode.

Electrically, I studied the waveform on my test ECU carefully. I also calibrated the 'scope to ensure I was seeing the truth. Although the mark:space ratio of the squarewave was considerably more space than mark, it was clean and swinging between 0V and full battery voltage and showing no signs of triangulation (suggesteing a thermal shutdown) or other distortion. Also, I listened carefully and the valves were clicking to soft mode with a loud click, which suggested the combined hydraulic pressure and magnetic field were doing their job to cleanly and fully switch the valve. I oberved, on switching, a big spurt of LHM in my temporary transparent leakage return pipe as expected followed by the steady but heavy flow when the valve was in soft mode. Leakage in hard mode was zero.

I shall do more and more tests in due course with new valves to get exactly what happens and what leakage rates can be expected. I'll also determine a normal waveform from the ECU. I'll try to get hold of another spare ECU so I have more references.