# Weird Hicas Situation



## Guest (Sep 19, 2002)

Folks, I think I have confused my Hicas controller - can anyone shed some light on this?

The battery went totally flat for a day and I recharged it.
I have also installed an amp and rear shelf speakers.

Here is the problem:

When driving in as straight a line as you can on the isle of wight, apropo of nothing the back end of my GTR33 skips. Now this is not a 'over drain wobble' but it is literally as if someone has steered the car via the rear wheels. It is quite pronounced and a tad alarming!

It is not tramline or the back end wobble my 300zx used to suffer from but it feels as though the hicas is moving the rear wheels.

I find this real strange as I would not have thought the HICAS system could move the wheels the amount needed to make the car feel like this.

Strange....

Any help gratefully pondered upon... soz to chuck this in here, did run search

Thanks


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## s2gtr (Jun 30, 2001)

I have exactly the same problem with mine but only when I turn the stereo up to approx 3/4 volume or above. It has done this ever since I had the car nearly two years now a R33 1998 UK car.

I know that does not help you, but at least you are not alone!


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## SteveC (Jul 2, 2001)

does this happen at the same speeds each time ?

I had a problem where the rear end would jerk to the right at exactly 120 mph, nearly shat myself when it first happened !!

it also happened at slower speeds and at about 140.

I lived with it for a while thinking it was a "feature" but it frightened the life out of me so I took it to my mates garage.
it is a Nissan dealership and one of the top guys there said he remembered a similar thing with the 300zx's (which also use Hicass) it was a bit of play on the rear tracking rod.

Sure enough we lifter the car up and there was a barely discernable bit of play in the rear track rod arm. Up and down.

What it looked like was the car had been curbed at a slow speed in a car park (by me...Doh) and this pushed the track rod towards the ball joint it sits on. It was slightly compressed and resulted in a gnats **** worth of movement. This is picked up by the Hicass computer at high speed as a fairly sudden change of direction and hence the tail end snapping about.

new track rod ( about 60) and an hour later it was fixed..

the play is so slight as to be barely noticeable so get someone to have a lok at that who knows how it feels.

hope this is it because it is an easy one to fix.

cheers
Steve


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## Howsie (Feb 25, 2002)

*Thats why...*

this forum is so useful.

Good work fellas!


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## gtr-boy (Apr 12, 2002)

*hicas*

hicas is voltage sensitive - if your hi-fi is dropping the car voltage (loud bass?) it can do some odd stuff.

It would be worth looking at where your hi-fi is getting its power from - you may want to take a lead from the battery itself.


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## MattPayne (Apr 11, 2002)

*may also be...*

It could also be that the HICAS controller hasnt setup straight... 
When you reconnect the battery the HICAS ECU resets its self and it _assumes_ that the front wheels are straight, if they arnt, the rear wheels will point slightly in the wrong direction... 
to cure it you just need to disconnect the battery again, and make sure that the front wheels are straight when you reconect it...


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## Mad Maxis (Nov 13, 2001)

*HICAS TWITCH*

I can related to what s2gtr has to say, again I have a 98 UK car and it does exactly the same if the music is up to load.

We've had the car on the ramps where if you turn the volume up then you can see the rear wheels doing a little jig.

TOMIE do a HICAS lock which I'm considering at the moment, but I'd rather just loose the volume.

No track rod movement, I had that checked to confirm, but yes it either voltage related or thump of the speaker related.

Tesh


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## jae (Aug 28, 2002)

*120 Twitch*

I have a similar problem to Steve C, except it's a twitch to the left. Occurs at about 120, also occasionally under hard acceleration. On all occasions, the stereo has not been on. Thanks for the post as, like Steve, I thought it was 'one of those things'.


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## weston (Jun 30, 2001)

*I have the same*

but the back end feels funny if i'm in 5th & floor the right foot
at 18-2200 revs like the wheel isn't properly connected to the 
car.

Weird Feeling !

Weston


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## peatough (Oct 6, 2001)

*Hicas*

Hi


I have had the same problem with my 33GTR. 

I even took the car to Middlehursts who reset the battery and checked HICAS using Nissan diagnositic. No problem found.

This back end sensation ( Its proper brown trouser material - Feels like someone is driving back end of car ) is more commonly found where people have installed uprated hi-fi equipment. Even factory uprated cars ( with Kenwood Amp ) have this fault.

I was told that this fault is known to be caused due to vibration of a sensor located within the handbrake area ( think its this area ) which causes Hicas to play up. I know of several cars that have had this fault.

I will investigate further and try and find how to correct.

Hope this info helps

Pete


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## SteveC (Jul 2, 2001)

put mine on a consono and no fault, the chaps looking at the car then looked at me like I was mad so I took one them out. He also nearly shat himself.

Changed the component and all is good.

I get the odd twitch now and then but nothing like it was (this could be related to the stereo as I do have it loud sometimes..

scary stuff.

/Steve


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## r33 v-spec (May 24, 2002)

*Re: Hicas*



peatough said:


> *I was told that this fault is known to be caused due to vibration of a sensor located within the handbrake area ( think its this area ) which causes Hicas to play up. I know of several cars that have had this fault.
> *


Yeah thats true, because when I run my wires through the centre for my CD changer wire, I noticed a box which said something like "Caution do not touch/vibrate/move".

I'm sure its what your on about aswell, and its near the handbrake. 

This has put me off doing my audio system.


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## davewilkins (Jun 30, 2001)

*Hicas problems*

1) the hicas computer is near the speakers 
2) the g-sensors are near the handbrake

Would have some bearing on this I would think


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## Harry (Sep 1, 2002)

Hey...same problem

This happened to me coming down the M76 yesterday. It occurred on a particular part of the motorway (concrete pavement, v uneven). Scared the shit out of me (again felt like the read end steering itself). It cleared up after I hit asphalt and didnt reoccur...

I put it down to the pavement quality...maybe not

She does have an after market stereo fitted....


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## Guest (Sep 19, 2002)

*Wow*

What a response, I think we have hit upon something here.

I really thought it was something to do with my stereo install but couldn't see how Nissan would allow vibration to disturb the HICAS distribution - the reason is that before I installed a big amp and huge (ooer) sub in the boot I didnt have this phenomenon.

I have also installed a second amp (routed though the center console past the gearlever)..

The sub creates huge vibration, so much so that the mirrors vibrate as does the dash and all exterior trims etc.

Driving to work with sub on, rear wheel shuffle... I hadnt read these replies before setting out home but I figured I'd listen to the engine and exhaust note on the way home (better than any music!) and no rear end steer at all.

Im going to go out tomorrow and test this with big bass noise and then none at all.... Ill let you know

Thanks for all your replies... top forum, top people

Peace,


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## JasonO (Jun 29, 2001)

I've got a 10" sub, mounted in a free air configuration directly below the HICAS computer, the magnet can't be more than 2" away from the computer housing. I'm driving it with abt 400w and the amp is mounted in the space beside the battery.

I have not experienced any problems with the HICAS on my car (GTS25T) and think htis maybe point more to the centre gauge as the source of the problems you folks are experiencing.

Just my 2p worth, interesting topic BTW, be nice to hear how you get on tomorrow Senna.

Have you tried it listening to anything else than Steps and SClub though ?


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## peatough (Oct 6, 2001)

*Hicas*

Hi


Further to my email above I have checked with a Ex Middlehurst techn.

This HICAS fault we have described IS due to a G Sensor located within the handbrake assembly. 

Resonance from add on base units causes this. Also poor condition handbrake assembly ( mine was knackered ) plus wear and tear also contributes. 

Hope this helps 

Thanks

Pete


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## davewilkins (Jun 30, 2001)

*Info on G-sensors*

The following thread links to an interesting article where someone has modified the signal from the g-sensors to play with the handling of the car. There was only one reply to the post... from me. My car is fixed now by the way and the traction control unit broke so has been removed 
G-sensor link


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## Guest (Sep 19, 2002)

*you got a pm*



SteveC said:


> *does this happen at the same speeds each time ?
> 
> I had a problem where the rear end would jerk to the right at exactly 120 mph, nearly shat myself when it first happened !!
> 
> ...


Steve, You got a pm from me.


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## SteveC (Jul 2, 2001)

This is an interesting one. Dave, Emailed you back.

I do occasionally get a shimmy still and I do have a 12" rockford fosgate sub in the boot so this could clear it all up.

I always wondered why it only happens when I am driving slowly(relatively) and when I boot it it doesn't happen but I always turn down the sounds when I give it some ( I don't like the distraction) so that explains it. 

The fault I had with the track rod arm was like it but a LOT more violent. If it lasted for more than the split second it did I had the feeling I would have crashed the car.

cheers all.

/Steve


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## bnr34vspec2 (Jul 20, 2001)

So sounds like everyone that have this problem is with the R33 GTR.

Am I right to assume this problem is specific to the R33 GTR alone?

Jeff


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## Guest (Sep 20, 2002)

*?*

Not sure Jeff - but I took her out for a spin tonight and no bass - no skippy back end.

Crank up the 'Bring me the skull of Barry Manilow' CD and sure enough, wibble out rear steer!

An odd one indeed, perhaps Nissan's way of telling us to listen to exhaust notes and not 70's funkadelica


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## Henry (Jul 19, 2001)

*Sounds = Hicas Wobble*

Hi all,
About 4 years ago I had a big ICE system installed including big base box.Turn it to loud on the Motorway, drive on a straight bit and like magic the rear end starts dancing.

I proved it was the music but was laughed at by the professionals..........now this Thread has proved me right,thanks.

Eat Humble Pie You Skyline Gods 

The best rear end steer moment was this year in June heading up the A6 to Paris with my son,"little" Henry Jnr at 160mph windows down (no air-con) and playing the new Linken Park CD,wicked.

See ya,
Henry


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## tigger (Jan 3, 2002)

I think I get this too......loud music and the back end seems to have a life of its own....quite unnerving!!


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## jae (Aug 28, 2002)

*Twitch Again*

This is less than entertaining. On the way in this morning, had a blat, and sure enough, the back end twitched, but then kept doing so at irregular intervals for a couple of minutes. Allowing for road irregularities and tyre pressures being slightly down, any ideas as the stereo was not on.


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## SteveC (Jul 2, 2001)

sounds like the original problem I had.

check out the rear track rod.

I'll post some piccies on monday (if I remember.)

cheers
Steve


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## cipher (Oct 14, 2002)

HICAS is known for doing this if you have big amps in the boot, for some reason the current drain tends to upset HICAS.

The other reason, is if the battery was completely dead, then you recharged it. You did make sure that the wheels were PERFECTLY AND ABSOLUTLEY straight before introducing power to the system again didn't you?

Not sure what effect the latter would have, but I have seen enough ppl warning about having the wheels straight when resetting HICAS by a battery disconect (effectivly hat you done by letting it run dead), So it must cause some issues.


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## Tobes (Jul 15, 2002)

*Hicas.....*

This used to happen to my R33 also, i read on a previous thread that if the rear tyres are not evenly worn, eg you have odd tyres, this also messes with the hicas, i had the tyres replaced, and no further problems. So if you don't have the stereo on full and are still getting a lively rear end rolleyes: ) try checking the rear tyres.


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## m7law (Jan 16, 2002)

*Bass and wobbles !*

I had this problem when i first bought my R33 two years ago ... and had Middlehursts look see ... Raymond told me a tale of someone who had a really bad twitch when passing certain heavy trucks with a deep bass exhaust , when passing the truck car twitched wildly , he backed off and let truck catch him and exactly the same occurred again. Middlehursts conclusion was that the bass did interfere with Hicas just as a deep stereo bass could . 

Interesting to hear so many peeps with same handling difficulty. Its not so bad when you are more used to the cars behaviour but can be MIGHTY scary if it catches u unawares ... does me make me pretty cautious on the whole. 

I also found that as my tyres were pretty worn when first got the car that that affected it too.


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## Moschops (Sep 3, 2002)

My HICAS light has never come on (apart from when the ignition's on) so I wondered does it light up when HICAS kicks in or just when there's a problem? Can't say as I've ever felt it twitch, well that wasn't down to irregularities in the road anyway.


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## haplo (Dec 28, 2002)

***** twitching!*

Hmm, My R32 GTS-T has a tendency to skitter about the road in a most uncomfortable manner also, but I suspect not due to the audio system (crappy cd player at moment). Happens when the road is rough or i hit a minor unevenness. 
Went to abbey and it turns out rear struts are goosed. Specifically, the rear pax side, which is the one doing the wandering. 

Not sure if this helps but hey, its free to type here!


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## SteveC (Jul 2, 2001)

This is what I posted up that fixed mine.
the track rod arm was damaged on mine causing the same syptoms as discussed.

this was caused by curbing the car at about 4 mph in a car park.
it pushed the track rod arm into the socket it sits in and gave about 1mm of lateral play.

My mate diagnosed this fault in 2 minutes flat as it was quite a common one on 300zx's (which also uses the hicass system)

the moral is listen to everyone.

/Steve


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## Guest (Jan 28, 2003)

thanks for all the musings and ideas.

The GTR is off upto Abbey in a week and Ill get 'em to check the track rod ends

They are putting two new rears on so maybe that may clear up the butt-wobblers, Ill post back here when its done.

nice one,

Glen


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## GTuned (Mar 21, 2002)

Good Luck with the problems guys!

I was looking for patterns, like for instance, is it only on R33 GT-Rs but not on V-Specs etc.. but it seems we can all get it.. scary.

What does it feel like to have the back end "shift" at 120mph?

Oh and I guess that ends my "I want Bass" quest. Good, I'll use the money constructively elsewhere!


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## SteveC (Jul 2, 2001)

how it feels..

have you ever gone through a badly surfaced bit of road where the front end goes one way and the back trys to tramline in the rut.

I knew mine was mechanical as it only happened at certain speeds on certain bits of road, with or without the sounds on.

I noticed it at about 60 (very mild) 120 (a bit scary) and once at 140 (for testing purposes on a private road )
the one at 140 is what made me think I'd better get it sorted, I very nearly shat myself !!

It was the same sort of feeling as when you are driving a high sided van and get a gust of wind hits you side on. and as the speed increased so did the effect.

I was going to bedford Autodrome on a track day the following week and the back straight there is easy to achieve 145 on so I had to get it sorted.

good luck.
Steve


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## Alan (Jul 1, 2001)

Good question Guy 
I have a Bass system in my car an have never suffered from the above  
Mines a Vspec. 
It could also be the direction of the bass speakers, ie where are they firing to.
I have 2 x 8" Bazooka Tubes firing into each corner of the boot.
Maybe you guy,s that have had this problem have the speakers firing near or onto the electronics in the boot.
Maybe people could answer the question about car and direction of speakers?
Best regards Alan


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## haplo (Dec 28, 2002)

*Would it not*

be possible to shield the cabling for the amps/speakers or possible the HICAS control units in the boot?

Well, for those people with problems related to their sound systems?

Could be a bit pricey I guess, but then again, what isn't?


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## Harry (Sep 1, 2002)

only happenned to me once - standard speakers - sound up LOUD

dont play it LOUD anymore


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## GTuned (Mar 21, 2002)

Steve:

Sounds freaky. Once the HICAS "helped" me as I was blasting round a corner, and almost made me stuff the car... so I can imageine at 140mph how scary that must have been!

haplo:

From what I've been reading, it looks like the bass vibration and possibly the voltage drops to the HICAS system make the back end "nervous". Shielding cables though is always a good thing, for many other reasons, primarily noise/interference which also might affect electronics in the car.


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## nismobrown (Mar 6, 2002)

*TWITCHING*

I first noticed this on my last car(1997 gtr33v spec)the car I imported in late 1997 with 300 miles and was as new.The problem only showed up when I fitted a kenwood mask and cd changer as installed by middlehurst from new.When the volume was turned up and strangely, only on one song, the rear end would twitch violently and equally side to side.I rang up all the skyline tuners for advice but most thought I was talking through my **** so this post has made me happy and made me realise that I wasnt imagining it after all.By the way my gtr34 vspec has the same stereo fitted but no **** end twitch even playing the same track of the cd.STRANGE BUT TRUE.


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## Gazmo1 (Jul 30, 2001)

*It wasn't....................*

The Venga Boys track called the 'Venga Bus is coming' by any chance was it ?

Gaz.

I jest not.


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## Rupert (Jun 28, 2001)

*Big stereos and bouncy cars...*

I've got a fairly substantial Stereo installation that replaces the rear seats in their entirety and therefore is situated just behind the HICAS sensor next to the handbrake. Even at ear bleeding volumes with enough bass to shake out your fillings, my car’s back end stays straight and true. I do however have a huge capacitor to power the amps etc., and protect against current spikes through the car electronics. Is it therefore down to current fluctuations rather than physical vibration?

I personally back the physical vibrations theory, as I believe the HICAS sensors are made up of a number of delicate mercury micro switches that would be far more affected by vibration than anything else.

Just my two-penny-worth.

Rupert


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## stormuk (Mar 5, 2002)

Hmm mine wobbles around first and second and third but thats in the wet )

Seriously I have a vspec slip dif on mine and havent spotted anything odd hope it helps


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## tyndago (Oct 24, 2002)

Having the oppurtunity to drive quiet a few GT-R's , I have felt the rear end twitch several times in several cars. All R33's


Its fairly dramatic... Feels like the car is really trying to go its own way. Not something that feels fun.

None of the cars I drove had any kind of stereo in them.

On the dyno , with an R33 a little over 500rwhp it started pulling side to side violently . That was pretty scary. I just pulled the connector on the rack , and it worked as a temporary fix.


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## Robb (Oct 10, 2001)

Hey Sean,
How are ya?

I was doing a search on this topic becouse my car is doing this very thing. Very unsettling feeling indeed. My steering wheel also moves about a fist one way or the other while i drive in a straight line. Not cool.

No big speakers in my car.

When I stomp on it to pass someone, it totally feels like I'm going sideways. feels a little strange at 80mph.


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## IanH (Nov 23, 2002)

Looks like when they built the R34 they sorted out this problem as, like NismoBrown, I've got a boot install with the amp located next to the hicas computer and have it really loud but don't have any problems (even with all the dash & sourrounds vibrating alot - if it's the G-sensor near the handbrake causing problems)


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## Harry (Sep 1, 2002)

I've also noticed mine do it at around 80mph on a "rippled" concrete surface....My guess is that a vibration (be it generated from the road surface or from a speaker mounted nearby) is enough to upset the HICAS unit and generate the "ass shakes"


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## tyndago (Oct 24, 2002)

The G sensor near the handbrake - that is for the Attesa system (4wd) . The thing that says do not drop /distrub , etc.

Nothing to do with the Hicas . The Hicas uses the yaw rate sensor in the trunk though. That -steering inputs , and speed inputs.


I have never noticed it on an R32 Robb . But , if the fix for a 300z works on a R33 , then I would imagine the R32 would run into the same problems as the system in an R32 and 300Z are very similar.


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## SteveC (Jul 2, 2001)

The reason we found what was wrong with mine was that a mechanic I know has seen this fault a lot on 300zx's.

the knuckle joint on the rear control arm had been damaged during a small kurbing incident in a car park. (just clipped it driving into the exit) Not practicing drifting !!

when we replaced the arm everything was sweet again, the wierd thing was that it happened at exactly the same speeds and in the same places on my test track so I thought it was the road causing it like Harrys explaination, but it wasnt and changing the arm cured it on all roads.

I have felt the effects caused by an undulating road and they are similar but no where near as violent.

good luck.
Steve


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## keith (Jun 29, 2001)

Robb

you could also do what I have done to the rear end,my R33 had very bad rear end twitch 
what I done was pulled out the hicas fuse in the boot.
it is in the fuse box,next to the battery i think the fuse is green in colour,made the car a better drive.
i was told that the hicas is only ment to work between 30 and 100 mph anyway
not sure if this is 100% true.


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## PepsiGuru (Sep 16, 2002)

I posted on this a while back and I had the same problem with my car. Its also an R33 GTR. 

Anyways, I first found this problem on my cross country trip from California to New York. It did this on my way to Las Vegas. ( just imagine strong cross winds and this, I was going crazy ) I made it to New York and the problem hadn't showed its face for a while. Then this summer I went on a long 1 and 1/2 month vacation and when I got back the battery was completely drained. 

I had a bit of trouble charging the battery since the Alarm System had completely drained it. After a while it finally started up and all seemed fine. As soon as I hit the highway the backend began to twitch when the volume was raised on the radio. ( my radio is an Alpine MP3 Player with built in Amp and Infinity Kapa Speakers ) 

I did a bit of research on the radio install and noticed the power was taken from the radio power. ( Not from the battery directly as it should be ) So I had the radio power taken DIRECTLY from the batter and while I was add it, I noticed that the stock battery on the car was something that looked like a Motorcycle battery. I had this changed to a high ampage battery that looks more like a regular car battery ( in size ).

Since I have done this ( About 2 months ago ) the problem has not come up again. ) 

All in all, I think it has something to do with low voltage in the system and not vibrations. 


Irving 
GTR . . . .


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## GTuned (Mar 21, 2002)

Irving, I also have an Alpine Head unit and it came with a whole set of warning labels to wire it directly to the battery, as they draw higher current (20A) than the "average" head unit.

As for the cheesy stock battery.. well that went out a long time ago.. I found an Optima orange-top that fit right in just perfectly (removed the silly plastic battery tray).


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## Zilog (Oct 28, 2002)

Interesting....

I posted a long while back (my first post ) when I first bought my R33 GTR about this. I tried the disconnecting of the battery and setting the front wheels straight but it didn't stop the problem. 

I spoke to Abbey (Great guys!) while having the car serviced there and they mentioned that some GTR's seem to have the problem. 

There seems to be several possible reasons for it in my experience:

1/ Vibration from LOUD speakers - turn 'em down.

2/ Vibration from road. If I'm driving on a concrete ripple like surface on a motorway at 90 mph (almost gauranteed) it will perform the skyline wiggle.

3/ Electrics playing silly buggers. One of my brake lights blew, and I noticed that I didn't have the problem until I replace the bulb. An indicator blew about 5 days later and again I the problem didn't re-occur until I replace the bulb. I know it sounds mad but thats just my experience - toying with the idea of pulling out one of the bulbs and leaving it out for good!

I think there needs to be some kind of voltage 'smoother' or something in there somewhere. Would love to get to the bottom of it as in the dry I'm quite used to it but in the wet it it a whole different ball game!! I now keep a spare pair of underpants in the car - just in case 

For me, it really is beginning to spoil an other wise stunning car, I'm toying with the idea of selling it mainly due to this problem.

Keith - Does removing the fuse really solve the problem - i.e. are the wheel locked straight once you have done this ?? It may mean the difference of keeping or selling the car.

Z


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## tyndago (Oct 24, 2002)

Disconnecting it at the connector - afterwards I drove the car several hundred miles and never noticed anything.

Probably not the best thing though if you are out and about running around.

There is a Hicas lock available

Or you can remove the Hicas....less weight.


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## SteveC (Jul 2, 2001)

Zilog said:


> *Interesting....
> 
> I posted a long while back (my first post ) when I first bought my R33 GTR about this. I tried the disconnecting of the battery and setting the front wheels straight but it didn't stop the problem.
> 
> ...


Check the mechanicals as well.
Any play whatsoever in the rear track rod arms manifests itself as a wiggle at certain speeds/road conditions.

It takes 2 minutes to get the car on a ramp and feel the arms for play. mine had less than a millimeters worth of movement in and out. changing the arm fixed the problem.

In fact it was so slight we almost missed it. there should be no play whatsoever in the track rods. it was literally a click of movement.

hope this helps.
Steve


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## Zilog (Oct 28, 2002)

Thank Steve , very good point. 

I'll try and get it up on the ramps sometime next week (this week is far too hectic!) and see if there is any play. Might just replace them anyway - better safe than sorry 

I'll let you know if it solves the problem.


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## Rich C (Feb 16, 2003)

I have never experienced this problem but I am just about to fit a new stereo so it is of a lot of interest.

As someone said the G sensor it used by the Altessa system and not by HICAS added to the fact that if it was that susceptible to vibration in its position, knocking the centre console would cause equal if not greater gravitational force on the sensor. Sending the car loopy not good when you are reaching for you shades. 
So mechanical problems aside people that notice this when the stereo is loud would almost certainly be caused by one of three things:

Q1. Frequency of the sound output
Q2. Magnetic interference
Q3. Fluctuation of the Current from the battery

A1. Vehicles are subjected to a massive variation in frequencies between different road conditions, surfaces, speeds etc. Even though subs produce very low frequencies, many of these frequencies would be experienced in everyday driving. So for my money not the problem

A2. Possible but unlikely because the variation in magnetism is fairly small even at high volumes. You would experience this even at low volumes too.

A3. To me this is the most likely all units have a minimum operating voltage. Big Subs and amps consume LOTS of current. Any one with even a modest stereo system turned up loud will notice the lights dimming on the deep bass notes. So..

To fix it I reckon all you need is a stiffening Cap. This basically is a large capacitor (normally 1 farad) which stores current for the deep bass notes and insures a constant voltage supply to the amps etc.

I would be very interested to hear if anyone who uses stiffening caps for there stereo has every encountered this problem?

My guess would be that people that have this problem with out any stereo would be related to something else? As some of the threads have been suggesting loose track rod? If the problem is current related how about a low battery?

Not sure if this helps my two penith for what its worth

Rich


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## Jabberwock (Jun 24, 2003)

I have also experienced the rear end wiggle on my 33. It hasn't done it for a while now but it always did it when accelerating at Motorway speed on a rippled concrete surface - better leave the A12 alone then 

My experience suggests that it was not the stereo, so looking at all of the above, the common factor seems to be vibration. Each car will have different amounts of wear, setup, body stiffness etc according age and so forth, so the problem could well be caused by a resonant harmonic - from road vibration, stereo sounds or other source which upsets the Hicas momentarily. It is interesting that some reported cases sound worse than others.


Ken.


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## JasonO (Jun 29, 2001)

Has anyone experienced this on a non-GTR Skyline ?

Like the GTS, or even the 300ZX which only has the HICAS system.


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## boab (Aug 23, 2003)

i have started getting something like this happening to my GTSt.

i had to go buy a new battery today, as my car had sat for a few days awaiting a new window.

since putting the new battery in, i have noticed that when my car is over 60mph, when i lift my foot off the power, the car pulls to the left.

don't know if this is the same thing, but it is concerning!


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## JasonO (Jun 29, 2001)

Boab,
Were your front wheels pointing straight ahead when you connected the new battery ?

If not, then the HICAS may need reset, as it is easily confused.


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## PepsiGuru (Sep 16, 2002)

> i have noticed that when my car is over 60mph, when i lift my foot off the power, the car pulls to the left.


That sounds more like a tire pressure or bushing issue. 

We are talking about normal driving then "Bam" a jolt to the side from the rear. 

Irving
GTR . . .


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## Rupert (Jun 28, 2001)

*Big noises...*

I have a very large stereo fitted in my Skyline with a 2 Farad Capacitor in place. I have never experienced any HICAS interference at all. I did however, when I had a smaller stereo with no Cap fitted.

I go with the power fluctuation argument.

Regards,

Rupert


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## JasonO (Jun 29, 2001)

Rupert,
I have a large(ish) sub / amp all mounted very close (approx. 10cm away) to the HICAS controller and wired up without any caps in place. I have never suffered any problems with the HICAS.


I'm thinking this is a GTR only issue.


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## Demon Dave (Sep 15, 2002)

*So, now I'm more confused than ever...*

I've heard a lot of people attribute problems with HICAS to hi-power amps and subs in the boot...At the mo I have a clarion amp and subwoofer in a custom built box sitting in my garage doing nothing 'cause I don't want to go to all the hassle of fitting it in my R34 and find out the bl00dy thing is gonna start causing the car to waggle it's ass to da music!  

So far it seems, some people can run amps/subs without a problem and others cant. Knowing my luck, I'll fall into the latter catagory


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## s2gtr (Jun 30, 2001)

Demon Dave '666' post's  

Now seriously, I don,t think any R34-GTR owners have reported this fault?

Dave.


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## Demon Dave (Sep 15, 2002)

I was just thinking the same thing...

"Let him who hath understanding reckon the number of the beast...for it is a human number. It's number is six hundred and sixty-six... "


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## Moschops (Sep 3, 2002)

JasonO said:


> *I have a large(ish) sub / amp all mounted very close (approx. 10cm away) to the HICAS controller and wired up without any caps in place. I have never suffered any problems with the HICAS.*


Ditto here, never so mich as a twitch.


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## Jabberwock (Jun 24, 2003)

Any comments from the Skyline experts out there? ie the guys at Abbey and so forth, who fix things for us?

Come on guys, have you come across this before?




 
Ken


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## [email protected] (Jun 2, 2003)

We have exactly the same thing on Redline's R33 GTR. Happens between 80 and 120 and when the stereo (Kenwood with no amps (yet)) is on...

Thanks for everyones' advice, it's given us plenty to check out...


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## Demon Dave (Sep 15, 2002)

Going back through the thread, it is looking like this is (generally) a GTR only issue...

Perhaps, the HICAS system in a GTR is more sensitive to either electrical interference or vibrations from the bass...


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## Zilog (Oct 28, 2002)

Just another thought on this. The only time I have had this happen is when I driving in a straight line, never happened druing cornering. It's like the HICAS system is getting lateral G input etc so doesn't perform the wiggle to try and work out whats happening.

Anyone had it happen while cornering ?

Z


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## cipher (Oct 14, 2002)

this HICAS issue, is NOT a GT-R only thing.

I have experienced this in a GTS-4 that I was test-driving to buy.

The back end of the car decided that it would turn left at about 120!, was, erm, entertaining!.

This was the reason that I didnt buy the car. I now know what it was, and if i knew then what I know now, I would have that Skyline.


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## JasonO (Jun 29, 2001)

cipher said:


> *this HICAS issue, is NOT a GT-R only thing.
> 
> I have experienced this in a GTS-4 that I was test-driving to buy.
> *


 Ahhh, The GTS4 is a different kettle of fish from the GTS / GTS25T as it has a version of ATTESSA fitted.


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## chas (Sep 19, 2003)

*Sorry*

to drag this old one out again but thats the 4th time in 2 days 
that i've had [the wiggle]. i'm getting used to it but it's really
spoiling the whole enjoyment for me.
It's a different story if you want the back end out by chucking it into a corner but to happen when you don't expect it is getting 
tiresome.
I'm off to see marc at the garage on monday but if he can't get to the bottom of it then the cars gonna have to go.
It's no fun flooring it and not knowing if the back end is gonna 
want to pop out for a look.
 
Charlie.


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## Guest (Dec 13, 2003)

Well seeing as I was the twot that started this topic, I will add;

Mine is most definately related to voltage drop.

I have peformed the same experiment with different factors - the road always remaining the same:
[mp3 head unit/200w amp front/1000w amp rear/4x kappa inf/1x 12inch sub/no caps/amps wired direct to battery)

With no stereo or amps on - no wobble
With lots of bass cranking - pronounced and scary wobble
With no bass (derek and clive hehe) - quick wobble when Peter Cook coughs (often!) or Dudley screams "cant"

Now Peter Cook coughing is quite bassy but it is definately linked to the voltage drop which happens when the amps have to work hardest and not the actual bass frequency.

Doesn't explain the road vibes causing problems but does prove the Skyline has a problem with the electronics(or something) controlling the rear end and frankly I understand chas wanting to get shot of his car, as this is an VERY unsettling experience.

Mine only does this sort of predictably, if it did it at random I would not want to drive it. At all. Literally feels like another driver has clipped your rear quarter  

Drive safe,

Glen


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## russwestwood (Jul 11, 2007)

After 3 1/2 years from the last post, has anyone determined the exact cause of the problem?
Im just about to install a 12" RockfordFoosgate sub in my boot along with 2 amps, and wondering if it a good idea now. Good thing i stumbled across this thread!
Mine is an R34 by the way, and this Forum has helped me heaps since ive joined! Keep up the good work lads..


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## chas (Sep 19, 2003)

*Holy thread resurrection!!!!*

Mine was traced to a worn rear track rod end, saying that I still get the light on after about 7miles, use that as a guide for the engine up to temp now :chuckle: 

Glad I kept the car though.

Charlie.


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## lonewolf (Feb 2, 2007)

After nearly a year of ownership I have never experienced anything like this... that is until yesterday driving back from Abbey Motorsport. Just got onto the M25 heading for the M4, not 100m from the slip road near Godstone, in the fast lane (doing about 80ish) when the back end kicked out. Pulled over through four lanes of traffic to the hard shoulder and it was still snaking left-right, even as we were slowing down. We honestly thought for a second that a tyre had gone, or a wheel was loose.

Visual inspection revealed nothing out the ordinary so we carried on. It didn't happen again until the M25/M4 junction where it just kicked out twice, then at the next junction it just wobbled once. It was fine all the way back to Bristol from there. Nothing is felt through the steering until it kicks out.

I have lost all confidence in the car now, it really is a brown trouser time.

We did have music on, but not loud and I have no amps or subs. The battery was flat and was jump started, we honestly did not know about lining the wheels up, yet it drove from Bristol to Abbey without any problems at all. No hicas light after ignition, no other warnings.

I will be speaking with Scott at Abbey tomorrow to see what can be done. I will try reseting the hicas with the wheels straight this time, but I am in favor of hicas locking now. Something as unpredictable as that isn't good.

Tim


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## SteveC (Jul 2, 2001)

look at my post at the start of this thread maybe reply #3.

track rod.

get them checked out it could be that.

/Steve


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## lonewolf (Feb 2, 2007)

Thanks Steve, track rods have already been checked while it was at Abbey. They found nothing wrong with the car apart from a very slight amount of play in the rear steering rack. Not enough to cause this.

I'm fairly certain this was caused by our incorrect wheel alignment when we jump started it, combined with the poor surface of the M25. First chance I get I will reset the hicas ecu properly.


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## shade (Nov 28, 2006)

Just to bring this back up again, mine does this. It only seems to happen when playing loud music (just a new H/U, no amps or anything) and driving 'normally' in a straight line.

Both sides of my HICAS rack knuckles are worn and due to be replaced this week. It will be interesting to see if this cures my wobble.

Interestingly (maybe not? lol) my HICAS does not work. Never has since I've had the car. The light comes on and goes off with engine start. The motor has been checked and is working fine (Mark at Abbey thought it may be a stuck motor). 
Once the knuckles have been replaced I will do the HICAS diagnostic test and see if that shows anything.

I'll probably get it all working and decide I don't like it and fit a lockout bar!


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## JapFreak786 (Aug 29, 2003)

in my GTS,i've got a stupid loud ICE system,where the bass dims the lights inside and outside the car,but not once have i had an issue with the HICAS on my GTS,the GTR has not ICE bar standard,so it may be something else wrong with the car aswell?

i'm running 2 amps in the boot,and nothign wrong (yet)


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## nozza1 (Jan 13, 2007)

Same thing happened to me when i had my i.c.e installed. It was down to the battery being re-connected with the front wheels being out of line. Diconnected the battery, alligned wheels, connected the battery and all was fine.

Took middlehurst 2 months after my warranty had finished to sort it out, wanted me to pull out my credit card, but l refused and said they had to sort it out cause it was still under warranty.


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## gtr_jocky (Sep 27, 2007)

Thank god i thought i was the only one my r33gtr does this wobble in third on the pipe(no radio) bout 120 scary as hell thought to my self theres no way thats right what is the cure hicas locking bar???


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## Pistonbroke (Nov 7, 2004)

Someone may have already mentioned this, but I thought I'd put in my 2 pennies worth. If the wobble is triggered by a voltage drop from big amp sucking life out the battery. Fitting a power cap may help the problem. I used to own an FTO that had a tiny little battery on it. My sound system used to play havok with the electrics due to the stress it put on the battery. I fitted a power capacitor to the circuit and it sorted all my problems.


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## lonewolf (Feb 2, 2007)

I forgot about this thread, I have to report that since resetting the hicas computer I have had no strange wobbles since.


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## pupsi (Aug 29, 2006)

After reading this Thread, conclusion is, the problem is caused by a voltage drop in the electrics system. For my R33 GTR 1998 U.K car, I for one, will be installing a dual battery system with a split charger. The sound system having its own dedicated power supply, should eradicate this problem ??. Fingers crossed.


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## Bullitt (Jun 1, 2008)

hey guys. so I just got my r32 gt-r a week ago.

at first, I was wondering why the hell would this Godzilla inspire less confidence than my previous Lancer Evo 5. it felt as if the car suddenly steered itself when I reached 120 kph (only midly though still quite scary) 

I'm from the Philippines and Skylines are really really rare here, especially GT-Rs. because of this site, I tried the battery reset solution and I think it solved the problem. I thought this problem would be very hard to solve but I am so glad for this site. 

very very good forum:clap:! more power to you guys!!


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## Ian C (Jun 3, 2003)

Chaps,

Wanted to resurrect an old thread to throw more fuel on the fire:

Haven't used the car for last 2 weeks and as you may have guessed it, battery has completely died.
jump started it and all seemed well, left it plugged it to the charger for a couple of days, but i think the battery has had it, keeps dying on me after only few hours.

So, yesterday, got the 'rear wiggle', never experienced it before, so put it down to road surface.
Today, twice more on flat surfaces.
Obviously, with the battery the way it is, it's possible that the front wheels weren't straight the first time it went dead, so i'll sort that when i change the battery this week.........
BUT - when i got home today, i went to put the battery on charge and accidentally touched the HICAS ECU with my arm - sh!t it was seriously warm!
I'm guessing that the HICAS system is working continuously (even in a straight line) and then occasionally it throws a large input to remind you the car's knackered!

Either that or my ECU has failed and that's what's draining my battery!

Car was MOTd this week and no remarks regarding worn ball joints, but i'll look next time i put it on the lift.


To be concluded.......

Cheers.
ian


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## gtr_jocky (Sep 27, 2007)

Ihad his poblem all the time then changed the ecu to a mappable one and hasent done it since weird sensenation all the same wen it used to do it


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## Ian C (Jun 3, 2003)

New battery installed, 60 miles done today, no wiggles to report!


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## DrGtr (Jul 18, 2009)

so now its 1000000000000% that is the voltage fault? I hope i will never have this experience. for the ones who had this experience how scary is that thing? i thought that the hicas is actually doing very little correction just 1 decree or 2. is the car actually sliding ?do an opposite steering movement correct this ? and how dangerous is if an other car is in the other lane next to you? as i have noticed most of the people with this expirience are r32 and r33 how about r34 owners?


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## lonewolf (Feb 2, 2007)

DrGtr said:


> for the ones who had this experience how scary is that thing?


When you're doing 70ish down the motorway and the back end decides to steer itself for no reason... it's defiantly time for a new pair of pants!

Yes, hicas is only a degree or two but it can really mess you up. Imagine driving in a strait line down the motorway. For me it was like somebody else had a steering wheel on the rear wheels and was yanking it left and right :squintdan 

Only happened twice but I quickly had the hicas taken off with the cusco delete kit. Now no more worries about if or when it will do it again!


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## DrGtr (Jul 18, 2009)

i cant imagine that. but don't want to live it either , been paranoid for the gearbox now i will be thinking for the tail of the car, even though my car doesn't have any of these, i guess i will never go over 200 m/h again hehe just in case my tale goes right and left


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## SteveC (Jul 2, 2001)

it's quite entertaining at 140mph... feels like the car kicks left then right and then it's all over... not enough time to realy react to it but like Lonewolf said it is time to change your pants...

/Steve


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