Steering or Hicas issue? Jolting steering mid corner

[ookami]

I have a problem that I don't even know where to start diagnosing it.  My R34 GT-Four experiences a strange sensation in the steering where at the same point mid corner when completing > 70 degree turn at speeds higher than 15km\h the steering suddenly gets heavier for half a second and the steering wheel jolts slightly (easily reproduced on smaller roundabouts).  I have read a heap of posts on the effects of hicas problems and power steering assist but the fact I can reproduce the problem consistently I thought it was more a mechanical issue rather than an electrical issue.  The vehicle is insanely low (thanks to the previous owner) does this play havoc with the AWD system and steering?  The vehicle has the standard factory steering wheel.

 

 

[GTSBoy]

Low will not affect anything.

The simple answer is just to disable HICAS* (because of its love of the cawk) and if the problem persists then it is mechanical, in a steering joint.

The longer answer is that it could be either a HICAS problem or a problem with a steering joint (ie, tie rod end, most likely) and I can't see how it could be diagnosed over the 'net unless someone has had and solved the exact same issue.

*By "disable HICAS" I mean a complete HICAS delete kit.

[ookami]

I honestly hoped someone had a similar issue ?.  I have little faith the in local shops diagnosing the issue, due to my past experiences.  I'll give the Hicas removal a go and go on from there.  Thanks for your reply.

[Dobz]

Have you ruled out a slipping ps belt? Dry steer it on concrete back and forth in a fast motion to see if you can get it to slip. It will feel like jolting through the wheel accompanied with a heavy steering wheel.

[niZmO_Man]

I had the same issue on my R32 GT-R, the power steering would 'kick' randomly, especially while going around roundabouts, fun times. I guess the computer couldn't decide whether to put it in low speed or high speed mode.
I disconnected the smaller plug on the HICAS computer, problem solved. I believe it's a voltage issue with the computer and/or somewhere else.

[dr phil]

R34 GT Fours do not come with HICAS. I’d guess it occurs when 4wd gets engaged.
I have a sedan GT4, and my steering changes course pretty weirdly under similar circumstances, I have split radius rod bushes to fix, and I’m replacing the front lower ball joints, to see if that helps. I don’t get any kick or heavy steering in mine though.

[ookami]

I managed to get some time check out the car over the weekend, yes you are correct @dr phil... no Hicas!!  But piddley little S13 size driveshatfs ?.   The PS belt did squeal when I tested by dry steering, so I replaced the PS belt as it did look old and worn.  Dry steering again results in no belt squeal or slip but the random pulling or jerking remains when cornering.

I probably should have looked at the car myself before posting.  TBH this is the first time I've personally had the car in the air and I think it has every adjustable suspension arm that has a pillowball Nengun has to offer - so the problem could be anywhere.  I have ordered some new Tierod ends (had to buy genuine) so  I'll post again once I make some progress.  Thanks for all of your advice.