Hi, all.
about a sudden strange jerk,
being inspirated by Cjaran and other members' previous comments,
someday while doing citrobics, I blipped the gas pedal and a sudden jerk happened.
Those I have seen without blippings tend to happen when the doors were open, if my memory serves correctly.
and these sudden jerks are usually combinations of two short-stroke upward and downward with a rhythm just like EV's clicking sounds, cut in and out.
leaving doors open and electrovalve motion were kind of related somewhere, although I am not machanically minded enough to describe its rule in this situation
so, if I've got it right, the jerks seem to be related to EV motions and we don't need to be worried about old struts or something, I wish.
jerks are always followed by massive foamy bubbles, and these may come out of the electrovalves where abrupt changes of pressure take place while opening and shutting through continuous LHM stream of citrobics.
how do you think, and has somebody never experienced this strange citrobics-associated jerk with doors open?
Full Version about a sudden jerk in citroaerobics
Hi Mako, i'm not sure i fully understand the issues here. The anti dive/anti squat function, the de-energising of the EV's - operation of a 3.5s timer- , when the accelerator is rapidly depressed and released should have no noticeable effect while stationary if system hydraulic pressure is ok. When the ignition is first turned on the computer completes the test regime and energises the EV's, that is normal mode. If a door/boot is opened they are de-energised seperating the centre sphere from the system. If system hydraulic pressure is low, and the suspension is subjected to a movement by someone getting in to the car, the ride height will be affected and a jerk will take place as the height corrector opens. In a closed system foaming can only be caused by air/gas in the system being drawn in.
robertm
robertm
Hi, robert
sorry, it tooked this long time to review the hydractive circuit schema,
sorry, it tooked this long time to review the hydractive circuit schema,
QUOTE
The anti dive/anti squat function, the de-energising of the EV's - operation of a 3.5s timer- , when the accelerator is rapidly depressed and released should have no noticeable effect while stationary
I agree with you as long as stationary.
but when you are lowering the height by sliding down the height corrector lever in the cabin, there must be fast flowing of lhm through the hydractive block, rushing from the sinking suspension cylinders. and what will happen if the passage to go in the hydractive block suddenly changed ? that change will necessarily interfere with smooth lowering of supensions. but I cannot explain more rational details.
my this time experience reminded me of someone’s mention about EV in this forum bifore.
about door
there may be some misunderstanding,
when you open doors with engine turned off, you can hear clearly energized EV’s sound, so I have believed the door swich opens the EVs. but don’t know whether it always happens in various situations, couldn’ find the exact relation of doors and EVs in the Internet.
about air bubbles
it may be more difficult to know what happens in faster lhm streams.
the “air bubbles” in relation to acute negative pressure is one of the problems to prevent in the closed circuits in medical heart-lung machines. I don’t think the lhm circuits are carefully designed and maintained as much as medical equipments.
SHIN
Hi Shin, with respect to the door switches they trigger the energising of the EV's and the 30s timer, this timer will always time out or until vehicle speed exceeds 5mph.
robertm
robertm
Hi, Robertm.
thanks again for information
I just found a file explaining about hydractive 2 system by I dont know who, in which I could interpret " 30s timer rule" like opening dorrs always overide the abnormal hard mode for 30s.
and couldn't find probable cause of sudden jerks in question in the file.
by the way,
why is the suspension hard while high and low positions ? are the EVs deenegergized ?
SHIN
thanks again for information
I just found a file explaining about hydractive 2 system by I dont know who, in which I could interpret " 30s timer rule" like opening dorrs always overide the abnormal hard mode for 30s.
and couldn't find probable cause of sudden jerks in question in the file.
by the way,
why is the suspension hard while high and low positions ? are the EVs deenegergized ?
SHIN
Hi shin
I have just come across a "feature" of Hydractive 2 rear pipework with anti-sink that I did not know about.
When trying to reuse some recovered 3.5mm pipe that had a good flare and nut I cut it to length only to find a long thin stiff steel wire running along the centre of the pipe.
I put it down to a manufacturing fault with the pipe and used another spare bit.
That was some while ago.
Recently while making up pipes I found another pipe with the same centre wire present.
So I made some enquiries and was advised that these special pipes are part of the anti sink system to reduce flow rates on valve opening.
It seems that if you replace these pipes with standard ones the rear end of a XM fitted with anti-sink will occasionally drop like a stone onto the rear bump stops.
This may be nothing to do with your problem but I though it was worth recording somewhere on the site and your post seem to be a good place to put it.
Researching this is still ongoing so as I find out more I will add the information.
John
I have just come across a "feature" of Hydractive 2 rear pipework with anti-sink that I did not know about.
When trying to reuse some recovered 3.5mm pipe that had a good flare and nut I cut it to length only to find a long thin stiff steel wire running along the centre of the pipe.
I put it down to a manufacturing fault with the pipe and used another spare bit.
That was some while ago.
Recently while making up pipes I found another pipe with the same centre wire present.
So I made some enquiries and was advised that these special pipes are part of the anti sink system to reduce flow rates on valve opening.
It seems that if you replace these pipes with standard ones the rear end of a XM fitted with anti-sink will occasionally drop like a stone onto the rear bump stops.
This may be nothing to do with your problem but I though it was worth recording somewhere on the site and your post seem to be a good place to put it.
Researching this is still ongoing so as I find out more I will add the information.
John
John,
I also have found this "Wire in a Pipe" on a Anti Sink Xantia VSX Series 1 (1995 M reg it was) I thought nothing of it other then Ooooo Strange!
I also have found this "Wire in a Pipe" on a Anti Sink Xantia VSX Series 1 (1995 M reg it was) I thought nothing of it other then Ooooo Strange!
QUOTE (xmexclusive @ )
It seems that if you replace these pipes with standard ones the rear end of a XM fitted with anti-sink will occasionally drop like a stone onto the rear bump stops.
This may be nothing to do with your problem but I though it was worth recording somewhere on the site and your post seem to be a good place to put it.
Researching this is still ongoing so as I find out more I will add the information.
John
Interesting!!
I wonder if this feature (or the lack of it) is relevant to Noz's recently reported rapid rear sinking problem? See http://club-xm.com/forum/index.php?showtopic=5314
Which particular pipe is it that contains the wire insert?
Presumably the presence of the wire can only be confirmed by cutting open the pipe.
Ken
